From 76e09beb25f3b7190227f150225cabdd7c6bce4a Mon Sep 17 00:00:00 2001
From: Morgan Tocker <tocker@gmail.com>
Date: Mon, 8 Jun 2020 10:00:13 -0600
Subject: [PATCH 01/71] Remove usage of deprecated MySQL SQL_CALC_FOUND_ROWS

Signed-off-by: Morgan Tocker <tocker@gmail.com>
---
 src/wp-includes/class-wp-query.php        | 20 ++++++++++++--------
 src/wp-includes/class-wp-user-query.php   | 13 ++++++-------
 tests/phpunit/tests/query/noFoundRows.php |  8 ++++----
 3 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 5027f21cf0ade..81ca01c7f38c7 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -83,6 +83,14 @@ class WP_Query {
 	 */
 	public $request;
 
+	/**
+	 * Get post database count query
+	 *
+	 * @since xxx
+	 * @var string
+	 */
+	public $request_count;
+
 	/**
 	 * List of posts.
 	 *
@@ -2910,13 +2918,9 @@ public function get_posts() {
 			$orderby = 'ORDER BY ' . $orderby;
 		}
 
-		$found_rows = '';
-		if ( ! $q['no_found_rows'] && ! empty( $limits ) ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS';
-		}
-
-		$old_request   = "SELECT $found_rows $distinct $fields FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby $orderby $limits";
+		$old_request   = "SELECT $distinct $fields FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby $orderby $limits";
 		$this->request = $old_request;
+		$this->request_count = "SELECT COUNT($distinct {$wpdb->posts}.ID) FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby";
 
 		if ( ! $q['suppress_filters'] ) {
 			/**
@@ -2999,7 +3003,7 @@ public function get_posts() {
 			if ( $split_the_query ) {
 				// First get the IDs and then fill in the objects.
 
-				$this->request = "SELECT $found_rows $distinct {$wpdb->posts}.ID FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby $orderby $limits";
+				$this->request = "SELECT $distinct {$wpdb->posts}.ID FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby $orderby $limits";
 
 				/**
 				 * Filters the Post IDs SQL request before sending.
@@ -3238,7 +3242,7 @@ private function set_found_posts( $q, $limits ) {
 			 * @param string   $found_posts The query to run to find the found posts.
 			 * @param WP_Query $this        The WP_Query instance (passed by reference).
 			 */
-			$this->found_posts = $wpdb->get_var( apply_filters_ref_array( 'found_posts_query', array( 'SELECT FOUND_ROWS()', &$this ) ) );
+			$this->found_posts = $wpdb->get_var( apply_filters_ref_array( 'found_posts_query', array( $this->request_count, &$this ) ) );
 		} else {
 			if ( is_array( $this->posts ) ) {
 				$this->found_posts = count( $this->posts );
diff --git a/src/wp-includes/class-wp-user-query.php b/src/wp-includes/class-wp-user-query.php
index 02b0ff3814498..ce2eac02e271d 100644
--- a/src/wp-includes/class-wp-user-query.php
+++ b/src/wp-includes/class-wp-user-query.php
@@ -248,10 +248,6 @@ public function prepare_query( $query = array() ) {
 			$this->query_fields = "$wpdb->users.ID";
 		}
 
-		if ( isset( $qv['count_total'] ) && $qv['count_total'] ) {
-			$this->query_fields = 'SQL_CALC_FOUND_ROWS ' . $this->query_fields;
-		}
-
 		$this->query_from  = "FROM $wpdb->users";
 		$this->query_where = 'WHERE 1=1';
 
@@ -621,8 +617,12 @@ public function query() {
 			}
 
 			if ( isset( $qv['count_total'] ) && $qv['count_total'] ) {
+
 				/**
-				 * Filters SELECT FOUND_ROWS() query for the current WP_User_Query instance.
+				 * Return a total count of users.
+				 * Historically this ran SELECT FOUND_ROWS() after issuing the main query,
+				 * but since SQL_CALC_FOUND_ROWS is now deprecated from MySQL, it instead repeats
+				 * the same query with COUNT(*) instead of $this->query_fields.
 				 *
 				 * @since 3.2.0
 				 * @since 5.1.0 Added the `$this` parameter.
@@ -632,8 +632,7 @@ public function query() {
 				 * @param string $sql         The SELECT FOUND_ROWS() query for the current WP_User_Query.
 				 * @param WP_User_Query $this The current WP_User_Query instance.
 				 */
-				$found_users_query = apply_filters( 'found_users_query', 'SELECT FOUND_ROWS()', $this );
-
+				$found_users_query = apply_filters( 'found_users_query', "SELECT COUNT(*) $this->query_from $this->query_where", $this );
 				$this->total_users = (int) $wpdb->get_var( $found_users_query );
 			}
 		}
diff --git a/tests/phpunit/tests/query/noFoundRows.php b/tests/phpunit/tests/query/noFoundRows.php
index 7731194d49752..e39f767da743f 100644
--- a/tests/phpunit/tests/query/noFoundRows.php
+++ b/tests/phpunit/tests/query/noFoundRows.php
@@ -11,7 +11,7 @@ public function test_no_found_rows_default() {
 			)
 		);
 
-		$this->assertContains( 'SQL_CALC_FOUND_ROWS', $q->request );
+		$this->assertNotContains( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
 	public function test_no_found_rows_false() {
@@ -22,7 +22,7 @@ public function test_no_found_rows_false() {
 			)
 		);
 
-		$this->assertContains( 'SQL_CALC_FOUND_ROWS', $q->request );
+		$this->assertNotContains( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
 	public function test_no_found_rows_0() {
@@ -33,7 +33,7 @@ public function test_no_found_rows_0() {
 			)
 		);
 
-		$this->assertContains( 'SQL_CALC_FOUND_ROWS', $q->request );
+		$this->assertNotContains( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
 	public function test_no_found_rows_empty_string() {
@@ -44,7 +44,7 @@ public function test_no_found_rows_empty_string() {
 			)
 		);
 
-		$this->assertContains( 'SQL_CALC_FOUND_ROWS', $q->request );
+		$this->assertNotContains( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
 	public function test_no_found_rows_true() {

From a6648d895ff229a638c3251a762e4e0ea5193d0b Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 22:25:11 +0100
Subject: [PATCH 02/71] Add ticket references.

---
 tests/phpunit/tests/query/noFoundRows.php | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/tests/phpunit/tests/query/noFoundRows.php b/tests/phpunit/tests/query/noFoundRows.php
index 6c89f041131b6..81467e523565c 100644
--- a/tests/phpunit/tests/query/noFoundRows.php
+++ b/tests/phpunit/tests/query/noFoundRows.php
@@ -4,6 +4,10 @@
  * @group query
  */
 class Tests_Query_NoFoundRows extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 47280
+	 */
 	public function test_no_found_rows_default() {
 		$q = new WP_Query(
 			array(
@@ -14,6 +18,9 @@ public function test_no_found_rows_default() {
 		$this->assertStringNotContainsString( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
 	public function test_no_found_rows_false() {
 		$q = new WP_Query(
 			array(
@@ -25,6 +32,9 @@ public function test_no_found_rows_false() {
 		$this->assertStringNotContainsString( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
 	public function test_no_found_rows_0() {
 		$q = new WP_Query(
 			array(
@@ -36,6 +46,9 @@ public function test_no_found_rows_0() {
 		$this->assertStringNotContainsString( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
 	public function test_no_found_rows_empty_string() {
 		$q = new WP_Query(
 			array(
@@ -47,6 +60,9 @@ public function test_no_found_rows_empty_string() {
 		$this->assertStringNotContainsString( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
 	public function test_no_found_rows_true() {
 		$q = new WP_Query(
 			array(
@@ -58,6 +74,9 @@ public function test_no_found_rows_true() {
 		$this->assertStringNotContainsString( 'SQL_CALC_FOUND_ROWS', $q->request );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
 	public function test_no_found_rows_non_bool_cast_to_true() {
 		$q = new WP_Query(
 			array(
@@ -71,6 +90,7 @@ public function test_no_found_rows_non_bool_cast_to_true() {
 
 	/**
 	 * @ticket 29552
+	 * @ticket 47280
 	 */
 	public function test_no_found_rows_default_with_nopaging_true() {
 		$p = $this->factory->post->create();
@@ -88,6 +108,7 @@ public function test_no_found_rows_default_with_nopaging_true() {
 
 	/**
 	 * @ticket 29552
+	 * @ticket 47280
 	 */
 	public function test_no_found_rows_default_with_postsperpage_minus1() {
 		$p = $this->factory->post->create();

From 1a16fc354c79a705ba0568111d0c9179bdaf9552 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 22:25:39 +0100
Subject: [PATCH 03/71] Docs.

---
 src/wp-includes/class-wp-comment-query.php | 2 +-
 src/wp-includes/class-wp-network-query.php | 2 +-
 src/wp-includes/class-wp-query.php         | 2 +-
 src/wp-includes/class-wp-site-query.php    | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/wp-includes/class-wp-comment-query.php b/src/wp-includes/class-wp-comment-query.php
index 902bf25714792..17c8dcedea659 100644
--- a/src/wp-includes/class-wp-comment-query.php
+++ b/src/wp-includes/class-wp-comment-query.php
@@ -183,7 +183,7 @@ public function __call( $name, $arguments ) {
 	 *                                                      When used with `$offset`, `$offset` takes precedence. Default 1.
 	 *     @type int             $offset                    Number of comments to offset the query. Used to build
 	 *                                                      LIMIT clause. Default 0.
-	 *     @type bool            $no_found_rows             Whether to disable the `SQL_CALC_FOUND_ROWS` query.
+	 *     @type bool            $no_found_rows             Whether to disable the query to count found rows.
 	 *                                                      Default: true.
 	 *     @type string|array    $orderby                   Comment status or array of statuses. To use 'meta_value'
 	 *                                                      or 'meta_value_num', `$meta_key` must also be defined.
diff --git a/src/wp-includes/class-wp-network-query.php b/src/wp-includes/class-wp-network-query.php
index 94d89db1874cb..0af75acdae7e9 100644
--- a/src/wp-includes/class-wp-network-query.php
+++ b/src/wp-includes/class-wp-network-query.php
@@ -98,7 +98,7 @@ class WP_Network_Query {
 	 *     @type int          $number               Maximum number of networks to retrieve. Default empty (no limit).
 	 *     @type int          $offset               Number of networks to offset the query. Used to build LIMIT clause.
 	 *                                              Default 0.
-	 *     @type bool         $no_found_rows        Whether to disable the `SQL_CALC_FOUND_ROWS` query. Default true.
+	 *     @type bool         $no_found_rows        Whether to disable the query to count found rows. Default true.
 	 *     @type string|array $orderby              Network status or array of statuses. Accepts 'id', 'domain', 'path',
 	 *                                              'domain_length', 'path_length' and 'network__in'. Also accepts false,
 	 *                                              an empty array, or 'none' to disable `ORDER BY` clause. Default 'id'.
diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 8cf92d327fd4b..4a0af29521d0b 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -1943,7 +1943,7 @@ public function get_posts() {
 			$q['page'] = absint( $q['page'] );
 		}
 
-		// If true, forcibly turns off SQL_CALC_FOUND_ROWS even when limits are present.
+		// If true, forcibly turns off the query to count found rows even when limits are present.
 		if ( isset( $q['no_found_rows'] ) ) {
 			$q['no_found_rows'] = (bool) $q['no_found_rows'];
 		} else {
diff --git a/src/wp-includes/class-wp-site-query.php b/src/wp-includes/class-wp-site-query.php
index 703c9580f1e26..f2908f8b88065 100644
--- a/src/wp-includes/class-wp-site-query.php
+++ b/src/wp-includes/class-wp-site-query.php
@@ -127,7 +127,7 @@ class WP_Site_Query {
 	 *     @type int             $number                 Maximum number of sites to retrieve. Default 100.
 	 *     @type int             $offset                 Number of sites to offset the query. Used to build LIMIT clause.
 	 *                                                   Default 0.
-	 *     @type bool            $no_found_rows          Whether to disable the `SQL_CALC_FOUND_ROWS` query. Default true.
+	 *     @type bool            $no_found_rows          Whether to disable the query to count found rows. Default true.
 	 *     @type string|array    $orderby                Site status or array of statuses. Accepts:
 	 *                                                   - 'id'
 	 *                                                   - 'domain'

From 43a8da524185e98638e0ef6c7bfea1514bb29906 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 22:25:44 +0100
Subject: [PATCH 04/71] Todos.

---
 src/wp-includes/class-wp-comment-query.php | 2 +-
 src/wp-includes/class-wp-network-query.php | 2 +-
 src/wp-includes/class-wp-site-query.php    | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/wp-includes/class-wp-comment-query.php b/src/wp-includes/class-wp-comment-query.php
index 17c8dcedea659..fa370acf734f2 100644
--- a/src/wp-includes/class-wp-comment-query.php
+++ b/src/wp-includes/class-wp-comment-query.php
@@ -951,7 +951,7 @@ protected function get_comment_ids() {
 
 		$found_rows = '';
 		if ( ! $this->query_vars['no_found_rows'] ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS';
+			$found_rows = 'SQL_CALC_FOUND_ROWS'; // @TODO
 		}
 
 		$this->sql_clauses['select']  = "SELECT $found_rows $fields";
diff --git a/src/wp-includes/class-wp-network-query.php b/src/wp-includes/class-wp-network-query.php
index 0af75acdae7e9..eea0e870f483b 100644
--- a/src/wp-includes/class-wp-network-query.php
+++ b/src/wp-includes/class-wp-network-query.php
@@ -471,7 +471,7 @@ protected function get_network_ids() {
 
 		$found_rows = '';
 		if ( ! $this->query_vars['no_found_rows'] ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS';
+			$found_rows = 'SQL_CALC_FOUND_ROWS'; // @TODO
 		}
 
 		$this->sql_clauses['select']  = "SELECT $found_rows $fields";
diff --git a/src/wp-includes/class-wp-site-query.php b/src/wp-includes/class-wp-site-query.php
index f2908f8b88065..25f155740af0e 100644
--- a/src/wp-includes/class-wp-site-query.php
+++ b/src/wp-includes/class-wp-site-query.php
@@ -674,7 +674,7 @@ protected function get_site_ids() {
 
 		$found_rows = '';
 		if ( ! $this->query_vars['no_found_rows'] ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS';
+			$found_rows = 'SQL_CALC_FOUND_ROWS'; // @TODO
 		}
 
 		$this->sql_clauses['select']  = "SELECT $found_rows $fields";

From 0b98da89be9b722399e3fdbe53992349b5252fe9 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 22:52:26 +0100
Subject: [PATCH 05/71] More docs.

---
 src/wp-includes/class-wp-query.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 4a0af29521d0b..6a78ab21227e8 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3012,6 +3012,7 @@ public function get_posts() {
 			 * Filters the completed SQL query before sending.
 			 *
 			 * @since 2.0.0
+			 * @since x.x.x This query now no longer contains a `SQL_CALC_FOUND_ROWS` modifier.
 			 *
 			 * @param string   $request The complete SQL query.
 			 * @param WP_Query $query   The WP_Query instance (passed by reference).
@@ -3096,6 +3097,7 @@ public function get_posts() {
 				 * Filters the Post IDs SQL request before sending.
 				 *
 				 * @since 3.4.0
+				 * @since x.x.x This query now no longer contains a `SQL_CALC_FOUND_ROWS` modifier.
 				 *
 				 * @param string   $request The post ID request.
 				 * @param WP_Query $query   The WP_Query instance.
@@ -3332,6 +3334,7 @@ private function set_found_posts( $q, $limits ) {
 			 * Filters the query to run for retrieving the found posts.
 			 *
 			 * @since 2.1.0
+			 * @since x.x.x This query was changed...
 			 *
 			 * @param string   $found_posts_query The query to run to find the found posts.
 			 * @param WP_Query $query             The WP_Query instance (passed by reference).

From d62ae5f350f372662b12d0f63e1ed8e1ad68cd13 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 23:20:36 +0100
Subject: [PATCH 06/71] First pass at lazy loading the `found_posts` and
 `max_num_pages` property values.

---
 src/wp-includes/class-wp-query.php | 48 +++++++++++++++++++++++-------
 tests/phpunit/tests/post/query.php | 48 ++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 10 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 6a78ab21227e8..23a5654232f08 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -172,17 +172,21 @@ class WP_Query {
 	 * If limit clause was not used, equals $post_count.
 	 *
 	 * @since 2.1.0
+	 * @since x.x.x This value is now lazily loaded only when it's needed.
+	 *
 	 * @var int
 	 */
-	public $found_posts = 0;
+	private $found_posts = 0;
 
 	/**
 	 * The number of pages.
 	 *
 	 * @since 2.1.0
+	 * @since x.x.x This value is now lazily loaded only when it's needed.
+	 *
 	 * @var int
 	 */
-	public $max_num_pages = 0;
+	private $max_num_pages = 0;
 
 	/**
 	 * The number of comment pages.
@@ -460,6 +464,14 @@ class WP_Query {
 	 */
 	private $stopwords;
 
+	/**
+	 * Undocumented variable
+	 *
+	 * @since x.x.x
+	 * @var string
+	 */
+	private $limits = '';
+
 	private $compat_fields = array( 'query_vars_hash', 'query_vars_changed' );
 
 	private $compat_methods = array( 'init_query_flags', 'parse_tax_query' );
@@ -3046,7 +3058,7 @@ public function get_posts() {
 			/** @var int[] */
 			$this->posts      = array_map( 'intval', $this->posts );
 			$this->post_count = count( $this->posts );
-			$this->set_found_posts( $q, $limits );
+			$this->limits     = $limits;
 
 			return $this->posts;
 		}
@@ -3057,7 +3069,7 @@ public function get_posts() {
 			}
 
 			$this->post_count = count( $this->posts );
-			$this->set_found_posts( $q, $limits );
+			$this->limits     = $limits;
 
 			/** @var int[] */
 			$r = array();
@@ -3108,14 +3120,14 @@ public function get_posts() {
 
 				if ( $ids ) {
 					$this->posts = $ids;
-					$this->set_found_posts( $q, $limits );
+					$this->limits = $limits;
 					_prime_post_caches( $ids, $q['update_post_term_cache'], $q['update_post_meta_cache'] );
 				} else {
 					$this->posts = array();
 				}
 			} else {
 				$this->posts = $wpdb->get_results( $this->request );
-				$this->set_found_posts( $q, $limits );
+				$this->limits = $limits;
 			}
 		}
 
@@ -3314,15 +3326,24 @@ public function get_posts() {
 	 * for the current query.
 	 *
 	 * @since 3.5.0
+	 * @since x.x.x The `$q` and `$limits` parameters were made optional.
 	 *
 	 * @global wpdb $wpdb WordPress database abstraction object.
 	 *
-	 * @param array  $q      Query variables.
-	 * @param string $limits LIMIT clauses of the query.
+	 * @param array  $q      Optional. Query variables.
+	 * @param string $limits Optional. LIMIT clauses of the query.
 	 */
-	private function set_found_posts( $q, $limits ) {
+	private function set_found_posts( $q = null, $limits = null ) {
 		global $wpdb;
 
+		if ( null === $q ) {
+			$q = $this->query_vars;
+		}
+
+		if ( null === $limits ) {
+			$limits = $this->limits;
+		}
+
 		// Bail if posts is an empty array. Continue if posts is an empty string,
 		// null, or false to accommodate caching plugins that fill posts later.
 		if ( $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) ) {
@@ -3358,6 +3379,7 @@ private function set_found_posts( $q, $limits ) {
 		 * Filters the number of found posts for the query.
 		 *
 		 * @since 2.1.0
+		 * @since x.x.x This filter now only runs after the value is lazily loaded...
 		 *
 		 * @param int      $found_posts The number of posts found.
 		 * @param WP_Query $query       The WP_Query instance (passed by reference).
@@ -3662,14 +3684,20 @@ public function __construct( $query = '' ) {
 	}
 
 	/**
-	 * Make private properties readable for backward compatibility.
+	 * Make private properties readable for backward compatibility and lazy loading.
 	 *
 	 * @since 4.0.0
+	 * @since x.x.x The `found_posts` and `max_num_pages` properties are now lazily loaded.
 	 *
 	 * @param string $name Property to get.
 	 * @return mixed Property.
 	 */
 	public function __get( $name ) {
+		if ( 'found_posts' === $name || 'max_num_pages' === $name ) {
+			$this->set_found_posts();
+			return $this->$name;
+		}
+
 		if ( in_array( $name, $this->compat_fields, true ) ) {
 			return $this->$name;
 		}
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index e7def81a0c822..06119a1a13118 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -758,4 +758,52 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 
 		$this->assertIsInt( $q->found_posts );
 	}
+
+	public function test_found_posts_query_should_be_lazily_loaded() {
+		global $wpdb;
+
+		self::factory()->post->create_many( 5 );
+
+		$start = $wpdb->num_queries;
+
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+			)
+		);
+
+		// Count the queries
+		$before_found_posts = ( $wpdb->num_queries - $start );
+
+		// Fetch found posts
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		// Count the queries after fetching found posts
+		$after_found_posts = ( $wpdb->num_queries - $start );
+
+		// Repeat
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		$after_found_posts_again_1 = ( $wpdb->num_queries - $start );
+
+		// Repeat again
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		$after_found_posts_again_2 = ( $wpdb->num_queries - $start );
+
+		// Ensure the posts were not initially counted
+		$this->assertSame( 1, $before_found_posts );
+
+		// Ensure the counts are correct
+		$this->assertSame( 5, $found_posts );
+		$this->assertEquals( 3, $max_num_pages );
+
+		// Ensure subsequent counts only trigger one query
+		$this->assertSame( 2, $after_found_posts );
+		$this->assertSame( 2, $after_found_posts_again_1 );
+		$this->assertSame( 2, $after_found_posts_again_2 );
+	}
 }

From 69a5dd8967c3254ac69bca5bfc8be419d3ab91ca Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 23:26:37 +0100
Subject: [PATCH 07/71] Ensure repeated calls to the `found_posts` or
 `max_num_pages` properties don't trigger additional queries.

---
 src/wp-includes/class-wp-query.php | 9 +++++++--
 tests/phpunit/tests/post/query.php | 6 +++---
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 23a5654232f08..2719f43ab1330 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -176,7 +176,7 @@ class WP_Query {
 	 *
 	 * @var int
 	 */
-	private $found_posts = 0;
+	private $found_posts = null;
 
 	/**
 	 * The number of pages.
@@ -534,7 +534,7 @@ public function init() {
 		unset( $this->comment );
 		$this->comment_count         = 0;
 		$this->current_comment       = -1;
-		$this->found_posts           = 0;
+		$this->found_posts           = null;
 		$this->max_num_pages         = 0;
 		$this->max_num_comment_pages = 0;
 
@@ -3336,6 +3336,10 @@ public function get_posts() {
 	private function set_found_posts( $q = null, $limits = null ) {
 		global $wpdb;
 
+		if ( null !== $this->found_posts ) {
+			return;
+		}
+
 		if ( null === $q ) {
 			$q = $this->query_vars;
 		}
@@ -3347,6 +3351,7 @@ private function set_found_posts( $q = null, $limits = null ) {
 		// Bail if posts is an empty array. Continue if posts is an empty string,
 		// null, or false to accommodate caching plugins that fill posts later.
 		if ( $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) ) {
+			$this->found_posts = 0;
 			return;
 		}
 
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 06119a1a13118..7f32b81ef19a2 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -802,8 +802,8 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 		$this->assertEquals( 3, $max_num_pages );
 
 		// Ensure subsequent counts only trigger one query
-		$this->assertSame( 2, $after_found_posts );
-		$this->assertSame( 2, $after_found_posts_again_1 );
-		$this->assertSame( 2, $after_found_posts_again_2 );
+		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts );
+		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again_1 );
+		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again_2 );
 	}
 }

From c25537db3ecad48cf0e38c64e93ec32129d9e85d Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 6 Jan 2022 23:31:32 +0100
Subject: [PATCH 08/71] Extra queries are generated when term and meta caches
 are updated.

---
 tests/phpunit/tests/post/query.php | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 7f32b81ef19a2..fc520577d8688 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -769,6 +769,8 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 		$q = new WP_Query(
 			array(
 				'posts_per_page' => 2,
+				'update_post_term_cache' => false,
+				'update_post_meta_cache' => false,
 			)
 		);
 

From acc3f1f1b44f002b994bce24d09d10de4d149487 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Fri, 7 Jan 2022 00:10:58 +0100
Subject: [PATCH 09/71] Add some extra bytes to keep the computer happy.

---
 tests/phpunit/tests/post/query.php | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index fc520577d8688..8ccd86ab871d5 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -768,7 +768,7 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 
 		$q = new WP_Query(
 			array(
-				'posts_per_page' => 2,
+				'posts_per_page'         => 2,
 				'update_post_term_cache' => false,
 				'update_post_meta_cache' => false,
 			)
@@ -778,20 +778,20 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 		$before_found_posts = ( $wpdb->num_queries - $start );
 
 		// Fetch found posts
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		// Count the queries after fetching found posts
 		$after_found_posts = ( $wpdb->num_queries - $start );
 
 		// Repeat
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		$after_found_posts_again_1 = ( $wpdb->num_queries - $start );
 
 		// Repeat again
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		$after_found_posts_again_2 = ( $wpdb->num_queries - $start );

From ea95d463243fcf088dca8fb27439b0357c992bd8 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 10 Jan 2022 23:26:00 +0100
Subject: [PATCH 10/71] No need to repeat this twice.

---
 tests/phpunit/tests/post/query.php | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 8ccd86ab871d5..405e2677f8ad0 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -788,13 +788,7 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
-		$after_found_posts_again_1 = ( $wpdb->num_queries - $start );
-
-		// Repeat again
-		$found_posts   = $q->found_posts;
-		$max_num_pages = $q->max_num_pages;
-
-		$after_found_posts_again_2 = ( $wpdb->num_queries - $start );
+		$after_found_posts_again = ( $wpdb->num_queries - $start );
 
 		// Ensure the posts were not initially counted
 		$this->assertSame( 1, $before_found_posts );
@@ -805,7 +799,6 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 
 		// Ensure subsequent counts only trigger one query
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts );
-		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again_1 );
-		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again_2 );
+		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again );
 	}
 }

From 87a27558e4a147c451858bbc232b02e184cac472 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 10 Jan 2022 23:34:00 +0100
Subject: [PATCH 11/71] Move all this into a data provider.

---
 tests/phpunit/tests/post/query.php | 46 ++++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 405e2677f8ad0..24ef2adc423a1 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -759,19 +759,30 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 		$this->assertIsInt( $q->found_posts );
 	}
 
-	public function test_found_posts_query_should_be_lazily_loaded() {
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_found_posts_queries
+	 *
+	 * @param array    $args
+	 * @param int      $expected_posts
+	 * @param int      $expected_pages
+	 * @param callable $factory
+	 */
+	public function test_found_posts_query_should_be_lazily_loaded( array $args, $expected_posts, $expected_pages, $factory ) {
 		global $wpdb;
 
-		self::factory()->post->create_many( 5 );
+		call_user_func( $factory, self::factory() );
 
 		$start = $wpdb->num_queries;
 
 		$q = new WP_Query(
-			array(
-				'posts_per_page'         => 2,
-				'update_post_term_cache' => false,
-				'update_post_meta_cache' => false,
-			)
+			array_merge(
+				$args,
+				array(
+					'update_post_term_cache' => false,
+					'update_post_meta_cache' => false,
+				),
+			),
 		);
 
 		// Count the queries
@@ -794,11 +805,28 @@ public function test_found_posts_query_should_be_lazily_loaded() {
 		$this->assertSame( 1, $before_found_posts );
 
 		// Ensure the counts are correct
-		$this->assertSame( 5, $found_posts );
-		$this->assertEquals( 3, $max_num_pages );
+		$this->assertSame( $expected_posts, $found_posts );
+		$this->assertEquals( $expected_pages, $max_num_pages );
 
 		// Ensure subsequent counts only trigger one query
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts );
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again );
 	}
+
+	public function data_found_posts_queries() {
+		return array(
+
+			array(
+				'args' => array(
+					'posts_per_page' => 2,
+				),
+				'expected_posts' => 5,
+				'expected_pages' => 3,
+				'factory' => function( WP_UnitTest_Factory $factory ) {
+					$factory->post->create_many( 5 );
+				}
+			),
+
+		);
+	}
 }

From 1ec9bf755b2897ac84d355533210b08991d71797 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 10 Jan 2022 23:41:26 +0100
Subject: [PATCH 12/71] Docs.

---
 tests/phpunit/tests/post/query.php | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 24ef2adc423a1..bab0d449d2065 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -768,7 +768,7 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 	 * @param int      $expected_pages
 	 * @param callable $factory
 	 */
-	public function test_found_posts_query_should_be_lazily_loaded( array $args, $expected_posts, $expected_pages, $factory ) {
+	public function test_found_posts_should_be_lazily_loaded( array $args, $expected_posts, $expected_pages, $factory ) {
 		global $wpdb;
 
 		call_user_func( $factory, self::factory() );
@@ -799,6 +799,7 @@ public function test_found_posts_query_should_be_lazily_loaded( array $args, $ex
 		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
+		// Count the queries after fetching found posts a second time
 		$after_found_posts_again = ( $wpdb->num_queries - $start );
 
 		// Ensure the posts were not initially counted
@@ -808,7 +809,7 @@ public function test_found_posts_query_should_be_lazily_loaded( array $args, $ex
 		$this->assertSame( $expected_posts, $found_posts );
 		$this->assertEquals( $expected_pages, $max_num_pages );
 
-		// Ensure subsequent counts only trigger one query
+		// Ensure subsequent counts only triggered one query
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts );
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again );
 	}
@@ -816,7 +817,7 @@ public function test_found_posts_query_should_be_lazily_loaded( array $args, $ex
 	public function data_found_posts_queries() {
 		return array(
 
-			array(
+			'basic query' => array(
 				'args' => array(
 					'posts_per_page' => 2,
 				),

From 9dfbc3711dc7b20a681ac1eaff4f472ea1b5d382 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 11:44:17 +0100
Subject: [PATCH 13/71] Add tests that ensure the newly private properties are
 publicly accessible.

---
 tests/phpunit/tests/post/query.php | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index bab0d449d2065..9dcd9d9881649 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -759,6 +759,36 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 		$this->assertIsInt( $q->found_posts );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_property_is_present() {
+		$q = new WP_Query(
+			array(
+				'post_type' => 'post',
+			)
+		);
+
+		$this->assertTrue( property_exists( $q, 'found_posts' ) );
+		$this->assertObjectHasAttribute( 'found_posts', $q );
+		$this->assertNotNull( $q->found_posts );
+	}
+
+	/**
+	 * @ticket 47280
+	 */
+	public function test_max_num_pages_property_is_present() {
+		$q = new WP_Query(
+			array(
+				'post_type' => 'post',
+			)
+		);
+
+		$this->assertTrue( property_exists( $q, 'max_num_pages' ) );
+		$this->assertObjectHasAttribute( 'max_num_pages', $q );
+		$this->assertNotNull( $q->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider data_found_posts_queries

From 74c117efea42be720119ab59f302bb44cf6c94a0 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 12:49:26 +0100
Subject: [PATCH 14/71] This is a private method so its signature can be safely
 changed.

---
 src/wp-includes/class-wp-query.php | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 2719f43ab1330..2703140028aaf 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3326,27 +3326,19 @@ public function get_posts() {
 	 * for the current query.
 	 *
 	 * @since 3.5.0
-	 * @since x.x.x The `$q` and `$limits` parameters were made optional.
+	 * @since x.x.x The `$q` and `$limits` parameters were removed.
 	 *
 	 * @global wpdb $wpdb WordPress database abstraction object.
-	 *
-	 * @param array  $q      Optional. Query variables.
-	 * @param string $limits Optional. LIMIT clauses of the query.
 	 */
-	private function set_found_posts( $q = null, $limits = null ) {
+	private function set_found_posts() {
 		global $wpdb;
 
 		if ( null !== $this->found_posts ) {
 			return;
 		}
 
-		if ( null === $q ) {
-			$q = $this->query_vars;
-		}
-
-		if ( null === $limits ) {
-			$limits = $this->limits;
-		}
+		$q      = $this->query_vars;
+		$limits = $this->limits;
 
 		// Bail if posts is an empty array. Continue if posts is an empty string,
 		// null, or false to accommodate caching plugins that fill posts later.

From 9a8be540346256659c9ab17a1b611e6b94122d62 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 22:25:29 +0100
Subject: [PATCH 15/71] Whoops.

---
 tests/phpunit/tests/post/query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 9dcd9d9881649..a9d142e307a69 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -812,7 +812,7 @@ public function test_found_posts_should_be_lazily_loaded( array $args, $expected
 					'update_post_term_cache' => false,
 					'update_post_meta_cache' => false,
 				),
-			),
+			)
 		);
 
 		// Count the queries

From 48ebdd5f763f2d5893a48a8ab755df805d35fc37 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 22:30:58 +0100
Subject: [PATCH 16/71] Keep the coding standards bot happy.

---
 tests/phpunit/tests/post/query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index a9d142e307a69..f90461a302402 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -855,7 +855,7 @@ public function data_found_posts_queries() {
 				'expected_pages' => 3,
 				'factory' => function( WP_UnitTest_Factory $factory ) {
 					$factory->post->create_many( 5 );
-				}
+				},
 			),
 
 		);

From d111d93a9d28a08602d360553fd62659913d6dba Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 22:32:29 +0100
Subject: [PATCH 17/71] Another whoops.

---
 tests/phpunit/tests/post/query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index f90461a302402..66a57ddf5d655 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -811,7 +811,7 @@ public function test_found_posts_should_be_lazily_loaded( array $args, $expected
 				array(
 					'update_post_term_cache' => false,
 					'update_post_meta_cache' => false,
-				),
+				)
 			)
 		);
 

From 7bc9130c2c76ac63f318a0080b93293854be41ba Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 23:14:04 +0100
Subject: [PATCH 18/71] Introduce a dedicated and simpler tests for testing the
 accuracy of post counts.

---
 tests/phpunit/tests/post/query.php | 49 ++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 16 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 66a57ddf5d655..c3a3ebce1b1d8 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -791,27 +791,19 @@ public function test_max_num_pages_property_is_present() {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider data_found_posts_queries
-	 *
-	 * @param array    $args
-	 * @param int      $expected_posts
-	 * @param int      $expected_pages
-	 * @param callable $factory
 	 */
-	public function test_found_posts_should_be_lazily_loaded( array $args, $expected_posts, $expected_pages, $factory ) {
+	public function test_found_posts_should_be_lazily_loaded() {
 		global $wpdb;
 
-		call_user_func( $factory, self::factory() );
+		self::factory()->post->create_many( 5 );
 
 		$start = $wpdb->num_queries;
 
 		$q = new WP_Query(
-			array_merge(
-				$args,
-				array(
-					'update_post_term_cache' => false,
-					'update_post_meta_cache' => false,
-				)
+			array(
+				'posts_per_page'         => 2,
+				'update_post_term_cache' => false,
+				'update_post_meta_cache' => false,
 			)
 		);
 
@@ -836,14 +828,39 @@ public function test_found_posts_should_be_lazily_loaded( array $args, $expected
 		$this->assertSame( 1, $before_found_posts );
 
 		// Ensure the counts are correct
-		$this->assertSame( $expected_posts, $found_posts );
-		$this->assertEquals( $expected_pages, $max_num_pages );
+		$this->assertSame( 5, $found_posts );
+		$this->assertEquals( 3, $max_num_pages );
 
 		// Ensure subsequent counts only triggered one query
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts );
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_found_posts_queries
+	 *
+	 * @param array    $args
+	 * @param int      $expected_posts
+	 * @param int      $expected_pages
+	 * @param callable $factory
+	 */
+	public function test_found_posts_are_correct( array $args, $expected_posts, $expected_pages, $factory ) {
+		call_user_func( $factory, self::factory() );
+
+		$q = new WP_Query( $args );
+
+		$message = sprintf(
+			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
+			$q->request,
+			$q->request_count
+		);
+
+		// Ensure the counts are correct
+		$this->assertSame( $expected_posts, $q->found_posts, $message );
+		$this->assertEquals( $expected_pages, $q->max_num_pages, $message );
+	}
+
 	public function data_found_posts_queries() {
 		return array(
 

From ef7249991a02412a7f3aa270ff97403001e29dc4 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Tue, 11 Jan 2022 23:20:39 +0100
Subject: [PATCH 19/71] Ensure the count properties can be read by `isset()`.

---
 src/wp-includes/class-wp-query.php | 6 +++++-
 tests/phpunit/tests/post/query.php | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 2703140028aaf..7c2a8bd100ddd 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3701,7 +3701,7 @@ public function __get( $name ) {
 	}
 
 	/**
-	 * Make private properties checkable for backward compatibility.
+	 * Make private properties checkable for backward compatibility and lazy loading.
 	 *
 	 * @since 4.0.0
 	 *
@@ -3709,6 +3709,10 @@ public function __get( $name ) {
 	 * @return bool Whether the property is set.
 	 */
 	public function __isset( $name ) {
+		if ( 'found_posts' === $name || 'max_num_pages' === $name ) {
+			return true;
+		}
+
 		if ( in_array( $name, $this->compat_fields, true ) ) {
 			return isset( $this->$name );
 		}
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index c3a3ebce1b1d8..0e72371bb3856 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -769,6 +769,7 @@ public function test_found_posts_property_is_present() {
 			)
 		);
 
+		$this->assertTrue( isset( $q->found_posts ) );
 		$this->assertTrue( property_exists( $q, 'found_posts' ) );
 		$this->assertObjectHasAttribute( 'found_posts', $q );
 		$this->assertNotNull( $q->found_posts );
@@ -784,6 +785,7 @@ public function test_max_num_pages_property_is_present() {
 			)
 		);
 
+		$this->assertTrue( isset( $q->max_num_pages ) );
 		$this->assertTrue( property_exists( $q, 'max_num_pages' ) );
 		$this->assertObjectHasAttribute( 'max_num_pages', $q );
 		$this->assertNotNull( $q->max_num_pages );

From 6ebca810228f6f5fcce20b238b2879177f7a5b75 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 00:10:15 +0100
Subject: [PATCH 20/71] More tests, remove the data provider.

---
 tests/phpunit/tests/post/query.php | 83 +++++++++++++++++++++---------
 1 file changed, 60 insertions(+), 23 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 0e72371bb3856..181d9bc5cf744 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -840,17 +840,15 @@ public function test_found_posts_should_be_lazily_loaded() {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider data_found_posts_queries
-	 *
-	 * @param array    $args
-	 * @param int      $expected_posts
-	 * @param int      $expected_pages
-	 * @param callable $factory
 	 */
-	public function test_found_posts_are_correct( array $args, $expected_posts, $expected_pages, $factory ) {
-		call_user_func( $factory, self::factory() );
+	public function test_found_posts_are_correct_for_basic_query() {
+		self::factory()->post->create_many( 5 );
 
-		$q = new WP_Query( $args );
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+			)
+		);
 
 		$message = sprintf(
 			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
@@ -858,25 +856,64 @@ public function test_found_posts_are_correct( array $args, $expected_posts, $exp
 			$q->request_count
 		);
 
-		// Ensure the counts are correct
-		$this->assertSame( $expected_posts, $q->found_posts, $message );
-		$this->assertEquals( $expected_pages, $q->max_num_pages, $message );
+		$this->assertSame( 5, $q->found_posts, $message );
+		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
 
-	public function data_found_posts_queries() {
-		return array(
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_author_queries() {
+		$author = self::factory()->user->create();
+		self::factory()->post->create_many( 5 );
+		self::factory()->post->create_many( 5, array(
+			'post_author' => $author,
+		) );
 
-			'basic query' => array(
-				'args' => array(
-					'posts_per_page' => 2,
-				),
-				'expected_posts' => 5,
-				'expected_pages' => 3,
-				'factory' => function( WP_UnitTest_Factory $factory ) {
-					$factory->post->create_many( 5 );
-				},
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+				'author'         => $author,
+			)
+		);
+
+		$message = sprintf(
+			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
+			$q->request,
+			$q->request_count
+		);
+
+		$this->assertSame( 5, $q->found_posts, $message );
+		$this->assertEquals( 3, $q->max_num_pages, $message );
+	}
+
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_term_queries() {
+		$term = self::factory()->term->create_and_get();
+		self::factory()->post->create_many( 5 );
+		self::factory()->post->create_many( 5, array(
+			'tax_input' => array(
+				'post_tag' => array( $term->slug ),
 			),
+		) );
+
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+				'tag'            => $term->slug,
+			)
+		);
 
+		$message = sprintf(
+			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
+			$q->request,
+			$q->request_count
 		);
+
+		$this->assertSame( 5, $q->found_posts, $message );
+		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
+
 }

From c5d974ce0913dbaaf602449788241359c857c741 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:09:22 +0100
Subject: [PATCH 21/71] More assertions.

---
 tests/phpunit/tests/post/query.php | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 181d9bc5cf744..fbb7af3448216 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -813,6 +813,7 @@ public function test_found_posts_should_be_lazily_loaded() {
 		$before_found_posts = ( $wpdb->num_queries - $start );
 
 		// Fetch found posts
+		$post_count    = $q->post_count;
 		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
@@ -830,6 +831,7 @@ public function test_found_posts_should_be_lazily_loaded() {
 		$this->assertSame( 1, $before_found_posts );
 
 		// Ensure the counts are correct
+		$this->assertSame( 2, $post_count );
 		$this->assertSame( 5, $found_posts );
 		$this->assertEquals( 3, $max_num_pages );
 
@@ -856,6 +858,7 @@ public function test_found_posts_are_correct_for_basic_query() {
 			$q->request_count
 		);
 
+		$this->assertSame( 2, $q->post_count, $message );
 		$this->assertSame( 5, $q->found_posts, $message );
 		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
@@ -883,6 +886,7 @@ public function test_found_posts_are_correct_for_author_queries() {
 			$q->request_count
 		);
 
+		$this->assertSame( 2, $q->post_count, $message );
 		$this->assertSame( 5, $q->found_posts, $message );
 		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
@@ -912,6 +916,7 @@ public function test_found_posts_are_correct_for_term_queries() {
 			$q->request_count
 		);
 
+		$this->assertSame( 2, $q->post_count, $message );
 		$this->assertSame( 5, $q->found_posts, $message );
 		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}

From c95af1fbf6c8880c5dc2bf47fa0a94da6e858a6b Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:29:36 +0100
Subject: [PATCH 22/71] Correct the post counts for term queries.

---
 src/wp-includes/class-wp-query.php |  2 +-
 tests/phpunit/tests/post/query.php | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 7c2a8bd100ddd..0ce9932846213 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3017,7 +3017,7 @@ public function get_posts() {
 
 		$old_request   = "SELECT $distinct $fields FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby $orderby $limits";
 		$this->request = $old_request;
-		$this->request_count = "SELECT COUNT($distinct {$wpdb->posts}.ID) FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby";
+		$this->request_count = "SELECT COUNT($distinct {$wpdb->posts}.ID) FROM {$wpdb->posts} $join WHERE 1=1 $where";
 
 		if ( ! $q['suppress_filters'] ) {
 			/**
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index fbb7af3448216..119685a12bf5e 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -897,11 +897,11 @@ public function test_found_posts_are_correct_for_author_queries() {
 	public function test_found_posts_are_correct_for_term_queries() {
 		$term = self::factory()->term->create_and_get();
 		self::factory()->post->create_many( 5 );
-		self::factory()->post->create_many( 5, array(
-			'tax_input' => array(
-				'post_tag' => array( $term->slug ),
-			),
-		) );
+		$ids = self::factory()->post->create_many( 5 );
+
+		foreach ( $ids as $id ) {
+			wp_set_post_terms( $id, $term->slug );
+		}
 
 		$q = new WP_Query(
 			array(

From 5a89980e9d2d3a2238d321217ba18a91817c32a9 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:32:04 +0100
Subject: [PATCH 23/71] Test paged queries.

---
 tests/phpunit/tests/post/query.php | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 119685a12bf5e..bf75879e96997 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -863,6 +863,30 @@ public function test_found_posts_are_correct_for_basic_query() {
 		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_paged_query() {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+				'paged'          => 3,
+			)
+		);
+
+		$message = sprintf(
+			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
+			$q->request,
+			$q->request_count
+		);
+
+		$this->assertSame( 1, $q->post_count, $message );
+		$this->assertSame( 5, $q->found_posts, $message );
+		$this->assertEquals( 3, $q->max_num_pages, $message );
+	}
+
 	/**
 	 * @ticket 47280
 	 */

From dd03845fd0c989c183546e50a2166765ecc6baf3 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:33:39 +0100
Subject: [PATCH 24/71] Test meta queries.

---
 tests/phpunit/tests/post/query.php | 31 +++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index bf75879e96997..8d452c61e40da 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -918,7 +918,7 @@ public function test_found_posts_are_correct_for_author_queries() {
 	/**
 	 * @ticket 47280
 	 */
-	public function test_found_posts_are_correct_for_term_queries() {
+	public function test_found_posts_are_correct_for_tax_queries() {
 		$term = self::factory()->term->create_and_get();
 		self::factory()->post->create_many( 5 );
 		$ids = self::factory()->post->create_many( 5 );
@@ -945,4 +945,33 @@ public function test_found_posts_are_correct_for_term_queries() {
 		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_meta_queries() {
+		self::factory()->post->create_many( 5 );
+		$ids = self::factory()->post->create_many( 5 );
+
+		foreach ( $ids as $id ) {
+			add_post_meta( $id, 'my_meta', 'foo' );
+		}
+
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+				'meta_key'       => 'my_meta',
+			)
+		);
+
+		$message = sprintf(
+			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
+			$q->request,
+			$q->request_count
+		);
+
+		$this->assertSame( 2, $q->post_count, $message );
+		$this->assertSame( 5, $q->found_posts, $message );
+		$this->assertEquals( 3, $q->max_num_pages, $message );
+	}
+
 }

From 457f708515c2b8e0a99cdadc72217f0cf41ebeb2 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:36:07 +0100
Subject: [PATCH 25/71] Remove some duplication.

---
 tests/phpunit/tests/post/query.php | 64 ++++++++++--------------------
 1 file changed, 21 insertions(+), 43 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 8d452c61e40da..16f24be1aedb6 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -852,15 +852,9 @@ public function test_found_posts_are_correct_for_basic_query() {
 			)
 		);
 
-		$message = sprintf(
-			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
-			$q->request,
-			$q->request_count
-		);
-
-		$this->assertSame( 2, $q->post_count, $message );
-		$this->assertSame( 5, $q->found_posts, $message );
-		$this->assertEquals( 3, $q->max_num_pages, $message );
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
 	/**
@@ -876,15 +870,9 @@ public function test_found_posts_are_correct_for_paged_query() {
 			)
 		);
 
-		$message = sprintf(
-			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
-			$q->request,
-			$q->request_count
-		);
-
-		$this->assertSame( 1, $q->post_count, $message );
-		$this->assertSame( 5, $q->found_posts, $message );
-		$this->assertEquals( 3, $q->max_num_pages, $message );
+		$this->assertSame( 1, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
 	/**
@@ -904,15 +892,9 @@ public function test_found_posts_are_correct_for_author_queries() {
 			)
 		);
 
-		$message = sprintf(
-			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
-			$q->request,
-			$q->request_count
-		);
-
-		$this->assertSame( 2, $q->post_count, $message );
-		$this->assertSame( 5, $q->found_posts, $message );
-		$this->assertEquals( 3, $q->max_num_pages, $message );
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
 	/**
@@ -934,15 +916,9 @@ public function test_found_posts_are_correct_for_tax_queries() {
 			)
 		);
 
-		$message = sprintf(
-			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
-			$q->request,
-			$q->request_count
-		);
-
-		$this->assertSame( 2, $q->post_count, $message );
-		$this->assertSame( 5, $q->found_posts, $message );
-		$this->assertEquals( 3, $q->max_num_pages, $message );
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
 	/**
@@ -963,15 +939,17 @@ public function test_found_posts_are_correct_for_meta_queries() {
 			)
 		);
 
-		$message = sprintf(
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
+	protected static function get_count_message( WP_Query $query ) {
+		return sprintf(
 			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
-			$q->request,
-			$q->request_count
+			$query->request,
+			$query->request_count
 		);
-
-		$this->assertSame( 2, $q->post_count, $message );
-		$this->assertSame( 5, $q->found_posts, $message );
-		$this->assertEquals( 3, $q->max_num_pages, $message );
 	}
 
 }

From e2a1990133b3d401af64164e6175c21d8f129c5c Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:41:51 +0100
Subject: [PATCH 26/71] More coverage for `no_found_rows` values.

---
 tests/phpunit/tests/post/query.php | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 16f24be1aedb6..6ddccfd21a7f5 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -762,32 +762,40 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 	/**
 	 * @ticket 47280
 	 */
-	public function test_found_posts_property_is_present() {
+	public function test_found_posts_property_is_present_with_no_found_rows_false() {
 		$q = new WP_Query(
 			array(
-				'post_type' => 'post',
+				'post_type'     => 'post',
+				'no_found_rows' => false,
 			)
 		);
 
-		$this->assertTrue( isset( $q->found_posts ) );
 		$this->assertTrue( property_exists( $q, 'found_posts' ) );
-		$this->assertObjectHasAttribute( 'found_posts', $q );
+		$this->assertTrue( isset( $q->found_posts ) );
 		$this->assertNotNull( $q->found_posts );
+
+		$this->assertTrue( property_exists( $q, 'max_num_pages' ) );
+		$this->assertTrue( isset( $q->max_num_pages ) );
+		$this->assertNotNull( $q->max_num_pages );
 	}
 
 	/**
 	 * @ticket 47280
 	 */
-	public function test_max_num_pages_property_is_present() {
+	public function test_found_posts_property_is_present_with_no_found_rows_true() {
 		$q = new WP_Query(
 			array(
-				'post_type' => 'post',
+				'post_type'     => 'post',
+				'no_found_rows' => true,
 			)
 		);
 
-		$this->assertTrue( isset( $q->max_num_pages ) );
+		$this->assertTrue( property_exists( $q, 'found_posts' ) );
+		$this->assertTrue( isset( $q->found_posts ) );
+		$this->assertNotNull( $q->found_posts );
+
 		$this->assertTrue( property_exists( $q, 'max_num_pages' ) );
-		$this->assertObjectHasAttribute( 'max_num_pages', $q );
+		$this->assertTrue( isset( $q->max_num_pages ) );
 		$this->assertNotNull( $q->max_num_pages );
 	}
 

From 620c392cb8a746c7e5fd25b53f6bf1dd1561b4c3 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 11:44:03 +0100
Subject: [PATCH 27/71] Coding standards.

---
 tests/phpunit/tests/post/query.php | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 6ddccfd21a7f5..966b799848149 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -889,9 +889,12 @@ public function test_found_posts_are_correct_for_paged_query() {
 	public function test_found_posts_are_correct_for_author_queries() {
 		$author = self::factory()->user->create();
 		self::factory()->post->create_many( 5 );
-		self::factory()->post->create_many( 5, array(
-			'post_author' => $author,
-		) );
+		self::factory()->post->create_many(
+			5,
+			array(
+				'post_author' => $author,
+			)
+		);
 
 		$q = new WP_Query(
 			array(

From af266411a8d6d16abdedcd42bb5bb8729ab6825a Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 12:04:45 +0100
Subject: [PATCH 28/71] Ensure there are no errors and the counts are correct
 for empty queries.

---
 src/wp-includes/class-wp-query.php |  2 +-
 tests/phpunit/tests/post/query.php | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 0ce9932846213..c1d5fb2d3f2be 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3342,7 +3342,7 @@ private function set_found_posts() {
 
 		// Bail if posts is an empty array. Continue if posts is an empty string,
 		// null, or false to accommodate caching plugins that fill posts later.
-		if ( $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) ) {
+		if ( empty( $q ) || $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) ) {
 			$this->found_posts = 0;
 			return;
 		}
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 966b799848149..2b55e78f22ccf 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -848,6 +848,19 @@ public function test_found_posts_should_be_lazily_loaded() {
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_empty_query() {
+		self::factory()->post->create_many( 12 );
+
+		$q = new WP_Query();
+
+		$this->assertSame( 0, $q->post_count );
+		$this->assertSame( 0, $q->found_posts );
+		$this->assertEquals( 0, $q->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 */

From a3c968de72c17fe3c4dbfdd5670514240fa5f9a8 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 12:19:25 +0100
Subject: [PATCH 29/71] Add tests for queries with no limits or paging.

---
 tests/phpunit/tests/post/query.php | 38 +++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 2b55e78f22ccf..d866fa445ba57 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -858,7 +858,7 @@ public function test_found_posts_are_correct_for_empty_query() {
 
 		$this->assertSame( 0, $q->post_count );
 		$this->assertSame( 0, $q->found_posts );
-		$this->assertEquals( 0, $q->max_num_pages );
+		$this->assertSame( 0, $q->max_num_pages );
 	}
 
 	/**
@@ -878,6 +878,42 @@ public function test_found_posts_are_correct_for_basic_query() {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_query_with_no_limit() {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => -1,
+			)
+		);
+
+		$this->assertSame( 5, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		// You would expect this to be 1 but historically it's 0 for posts without paging
+		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
+	/**
+	 * @ticket 47280
+	 */
+	public function test_found_posts_are_correct_for_query_with_no_paging() {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'nopaging' => true,
+			)
+		);
+
+		$this->assertSame( 5, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		// You would expect this to be 1 but historically it's 0 for posts without paging
+		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 */

From d74745b69055fb7d59d6adb54c2d1f2482499c03 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 14:34:26 +0100
Subject: [PATCH 30/71] Run all the relevant tests with each of the available
 `fields` args.

---
 tests/phpunit/tests/post/query.php | 74 ++++++++++++++++++++++++++----
 1 file changed, 64 insertions(+), 10 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index d866fa445ba57..354cba124f35f 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -761,10 +761,14 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_property_is_present_with_no_found_rows_false() {
+	public function test_found_posts_property_is_present_with_no_found_rows_false( $fields ) {
 		$q = new WP_Query(
 			array(
+				'fields'        => $fields,
 				'post_type'     => 'post',
 				'no_found_rows' => false,
 			)
@@ -781,10 +785,14 @@ public function test_found_posts_property_is_present_with_no_found_rows_false()
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_property_is_present_with_no_found_rows_true() {
+	public function test_found_posts_property_is_present_with_no_found_rows_true( $fields ) {
 		$q = new WP_Query(
 			array(
+				'fields'        => $fields,
 				'post_type'     => 'post',
 				'no_found_rows' => true,
 			)
@@ -801,8 +809,11 @@ public function test_found_posts_property_is_present_with_no_found_rows_true() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_should_be_lazily_loaded() {
+	public function test_found_posts_should_be_lazily_loaded( $fields ) {
 		global $wpdb;
 
 		self::factory()->post->create_many( 5 );
@@ -811,6 +822,7 @@ public function test_found_posts_should_be_lazily_loaded() {
 
 		$q = new WP_Query(
 			array(
+				'fields'                 => $fields,
 				'posts_per_page'         => 2,
 				'update_post_term_cache' => false,
 				'update_post_meta_cache' => false,
@@ -863,12 +875,16 @@ public function test_found_posts_are_correct_for_empty_query() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_basic_query() {
+	public function test_found_posts_are_correct_for_basic_query( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
 			array(
+				'fields'         => $fields,
 				'posts_per_page' => 2,
 			)
 		);
@@ -880,12 +896,16 @@ public function test_found_posts_are_correct_for_basic_query() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_query_with_no_limit() {
+	public function test_found_posts_are_correct_for_query_with_no_limit( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
 			array(
+				'fields'         => $fields,
 				'posts_per_page' => -1,
 			)
 		);
@@ -898,12 +918,16 @@ public function test_found_posts_are_correct_for_query_with_no_limit() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_query_with_no_paging() {
+	public function test_found_posts_are_correct_for_query_with_no_paging( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
 			array(
+				'fields'   => $fields,
 				'nopaging' => true,
 			)
 		);
@@ -916,12 +940,16 @@ public function test_found_posts_are_correct_for_query_with_no_paging() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_paged_query() {
+	public function test_found_posts_are_correct_for_paged_query( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
 			array(
+				'fields'         => $fields,
 				'posts_per_page' => 2,
 				'paged'          => 3,
 			)
@@ -934,8 +962,11 @@ public function test_found_posts_are_correct_for_paged_query() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_author_queries() {
+	public function test_found_posts_are_correct_for_author_queries( $fields ) {
 		$author = self::factory()->user->create();
 		self::factory()->post->create_many( 5 );
 		self::factory()->post->create_many(
@@ -947,6 +978,7 @@ public function test_found_posts_are_correct_for_author_queries() {
 
 		$q = new WP_Query(
 			array(
+				'fields'         => $fields,
 				'posts_per_page' => 2,
 				'author'         => $author,
 			)
@@ -959,8 +991,11 @@ public function test_found_posts_are_correct_for_author_queries() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_tax_queries() {
+	public function test_found_posts_are_correct_for_tax_queries( $fields ) {
 		$term = self::factory()->term->create_and_get();
 		self::factory()->post->create_many( 5 );
 		$ids = self::factory()->post->create_many( 5 );
@@ -971,6 +1006,7 @@ public function test_found_posts_are_correct_for_tax_queries() {
 
 		$q = new WP_Query(
 			array(
+				'fields'         => $fields,
 				'posts_per_page' => 2,
 				'tag'            => $term->slug,
 			)
@@ -983,8 +1019,11 @@ public function test_found_posts_are_correct_for_tax_queries() {
 
 	/**
 	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
 	 */
-	public function test_found_posts_are_correct_for_meta_queries() {
+	public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 		self::factory()->post->create_many( 5 );
 		$ids = self::factory()->post->create_many( 5 );
 
@@ -994,6 +1033,7 @@ public function test_found_posts_are_correct_for_meta_queries() {
 
 		$q = new WP_Query(
 			array(
+				'fields'         => $fields,
 				'posts_per_page' => 2,
 				'meta_key'       => 'my_meta',
 			)
@@ -1004,6 +1044,20 @@ public function test_found_posts_are_correct_for_meta_queries() {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	public function dataFields() {
+		return array(
+			'posts' => array(
+				'',
+			),
+			'ids' => array(
+				'ids',
+			),
+			'parents' => array(
+				'id=>parent',
+			),
+		);
+	}
+
 	protected static function get_count_message( WP_Query $query ) {
 		return sprintf(
 			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",

From 22095a1eb80ad8e1c3fa3541b755e6b2945e2621 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 15:16:26 +0100
Subject: [PATCH 31/71] Support PHP and JSON serialization.

---
 src/wp-includes/class-wp-query.php | 28 ++++++++++++-
 tests/phpunit/tests/post/query.php | 66 ++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index c1d5fb2d3f2be..f5f7c2ddd3bca 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -15,7 +15,7 @@
  * @since 1.5.0
  * @since 4.5.0 Removed the `$comments_popup` property.
  */
-class WP_Query {
+class WP_Query implements JsonSerializable {
 
 	/**
 	 * Query vars set by the user.
@@ -3734,6 +3734,32 @@ public function __call( $name, $arguments ) {
 		return false;
 	}
 
+	/**
+	 * Controls how the object is represented during PHP serialization.
+	 *
+	 * @since x.x.x
+	 *
+	 * @return array The properties of the object as an associative array.
+	 */
+	public function __serialize() {
+		$this->set_found_posts();
+
+		return get_object_vars( $this );
+	}
+
+	/**
+	 * Controls how the object is represented during JSON serialization.
+	 *
+	 * @since x.x.x
+	 *
+	 * @return array The properties of the object as an associative array.
+	 */
+	public function jsonSerialize() {
+		$this->set_found_posts();
+
+		return get_object_vars( $this );
+	}
+
 	/**
 	 * Is the query for an existing archive page?
 	 *
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 354cba124f35f..578fb8420220b 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -807,6 +807,72 @@ public function test_found_posts_property_is_present_with_no_found_rows_true( $f
 		$this->assertNotNull( $q->max_num_pages );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_property_is_present_in_php_serialized_query( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+			)
+		);
+
+		$serialized = serialize( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = unserialize( $serialized );
+
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 5, $unserialized->found_posts );
+
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertEquals( 3, $unserialized->max_num_pages );
+	}
+
+	/**
+	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_property_is_present_in_json_serialized_query( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+			)
+		);
+
+		$serialized = json_encode( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = json_decode( $serialized );
+
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 5, $unserialized->found_posts );
+
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertEquals( 3, $unserialized->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider dataFields

From 64e6363f91c008812ba5a6af721cc3891c3e8b41 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 15:17:56 +0100
Subject: [PATCH 32/71] Be more specific about this guard condition.

---
 src/wp-includes/class-wp-query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index f5f7c2ddd3bca..1d3e7eb0b9ed3 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3342,7 +3342,7 @@ private function set_found_posts() {
 
 		// Bail if posts is an empty array. Continue if posts is an empty string,
 		// null, or false to accommodate caching plugins that fill posts later.
-		if ( empty( $q ) || $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) ) {
+		if ( ! isset( $q['no_found_rows'] ) || $q['no_found_rows'] || ( is_array( $this->posts ) && ! $this->posts ) ) {
 			$this->found_posts = 0;
 			return;
 		}

From 940890938c5e65526d87593ed77a2784439628d8 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 15:19:38 +0100
Subject: [PATCH 33/71] Coding standards.

---
 tests/phpunit/tests/post/query.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 578fb8420220b..cb4f3cd9bf88d 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1112,10 +1112,10 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 
 	public function dataFields() {
 		return array(
-			'posts' => array(
+			'posts'   => array(
 				'',
 			),
-			'ids' => array(
+			'ids'     => array(
 				'ids',
 			),
 			'parents' => array(

From 92059b3126e89e9575185ead060b7dca022ea7dd Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 15:59:53 +0100
Subject: [PATCH 34/71] Implement serialization in a way that's compatible with
 PHP 5.6 to 8.1.

---
 src/wp-includes/class-wp-query.php | 43 +++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 1d3e7eb0b9ed3..8e32d1ba46a25 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -15,7 +15,7 @@
  * @since 1.5.0
  * @since 4.5.0 Removed the `$comments_popup` property.
  */
-class WP_Query implements JsonSerializable {
+class WP_Query implements JsonSerializable, Serializable {
 
 	/**
 	 * Query vars set by the user.
@@ -3739,6 +3739,19 @@ public function __call( $name, $arguments ) {
 	 *
 	 * @since x.x.x
 	 *
+	 * @return string The PHP serialized representation of the object.
+	 */
+	public function serialize() {
+		return serialize( $this->__serialize() );
+	}
+
+	/**
+	 * Controls how the object is represented during PHP serialization.
+	 *
+	 * Used by PHP >= 7.4.
+	 *
+	 * @since x.x.x
+	 *
 	 * @return array The properties of the object as an associative array.
 	 */
 	public function __serialize() {
@@ -3747,6 +3760,34 @@ public function __serialize() {
 		return get_object_vars( $this );
 	}
 
+	/**
+	 * Controls how the object is reconstructed from a PHP serialized representation.
+	 *
+	 * @since x.x.x
+	 *
+	 * @param string $data The PHP serialized representation of the object.
+	 * @return void
+	 */
+	public function unserialize( $data ) {
+		$this->__unserialize( unserialize( $data ) );
+	}
+
+	/**
+	 * Controls how the object is reconstructed from a PHP serialized representation.
+	 *
+	 * Used by PHP >= 7.4.
+	 *
+	 * @since x.x.x
+	 *
+	 * @param array $data The associative array representation of the object.
+	 * @return void
+	 */
+	public function __unserialize( $data ) {
+		foreach ( $data as $key => $value ) {
+			$this->$key = $value;
+		}
+	}
+
 	/**
 	 * Controls how the object is represented during JSON serialization.
 	 *

From 262ad2ebe9f83c45c03fd0f84221c5001149a55b Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 19:36:51 +0100
Subject: [PATCH 35/71] Ignore PHPCS warnings about the magic serialization
 methods.

---
 src/wp-includes/class-wp-query.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 8e32d1ba46a25..7259cf9ebfc57 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3754,7 +3754,7 @@ public function serialize() {
 	 *
 	 * @return array The properties of the object as an associative array.
 	 */
-	public function __serialize() {
+	public function __serialize() { // phpcs:ignore PHPCompatibility.FunctionNameRestrictions.NewMagicMethods.__serializeFound
 		$this->set_found_posts();
 
 		return get_object_vars( $this );
@@ -3782,7 +3782,7 @@ public function unserialize( $data ) {
 	 * @param array $data The associative array representation of the object.
 	 * @return void
 	 */
-	public function __unserialize( $data ) {
+	public function __unserialize( $data ) { // phpcs:ignore PHPCompatibility.FunctionNameRestrictions.NewMagicMethods.__unserializeFound
 		foreach ( $data as $key => $value ) {
 			$this->$key = $value;
 		}

From 70316e1d5b2ed1aba340f1ba40e16213b681013d Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 22:08:07 +0100
Subject: [PATCH 36/71] Add a test for a filter on `posts_request` that uses
 `SQL_CALC_FOUND_ROWS`.

---
 tests/phpunit/tests/post/query.php | 40 ++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index cb4f3cd9bf88d..18e7eea7533bc 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1110,6 +1110,46 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 */
+	public function test_posts_are_counted_with_select_found_rows_when_query_includes_sql_calc_found_rows() {
+		// Create five published posts.
+		self::factory()->post->create_many( 5 );
+		// Create ten draft posts.
+		self::factory()->post->create_many(
+			10,
+			array(
+				'post_status' => 'draft',
+			)
+		);
+
+		add_filter( 'posts_request', function( $request ) {
+			global $wpdb;
+
+			return "
+				SELECT SQL_CALC_FOUND_ROWS {$wpdb->posts}.ID
+				FROM {$wpdb->posts}
+				WHERE 1=1
+				AND {$wpdb->posts}.post_type = 'post'
+				AND {$wpdb->posts}.post_status = 'draft'
+				ORDER BY {$wpdb->posts}.post_date
+				DESC LIMIT 0, 2
+			";
+		} );
+
+		$q = new WP_Query(
+			array(
+				'posts_per_page' => 2,
+			)
+		);
+
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 10, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 5, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
+
 	public function dataFields() {
 		return array(
 			'posts'   => array(

From cc927eeae526d0702c222e8666ba12e2c056cdc8 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 22:15:27 +0100
Subject: [PATCH 37/71] Add back compat in case anything uses the
 `posts_request` filter and reinstates the `SQL_CALC_FOUND_ROWS` modifier.

---
 src/wp-includes/class-wp-query.php | 40 ++++++++++++++++++++++++++----
 tests/phpunit/tests/post/query.php |  1 +
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 7259cf9ebfc57..e23c9cd7e2601 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -188,6 +188,15 @@ class WP_Query implements JsonSerializable, Serializable {
 	 */
 	private $max_num_pages = 0;
 
+	/**
+	 * Undocumented variable
+	 *
+	 * @since x.x.x
+	 *
+	 * @var bool
+	 */
+	private $use_calc_found_rows = false;
+
 	/**
 	 * The number of comment pages.
 	 *
@@ -3024,12 +3033,17 @@ public function get_posts() {
 			 * Filters the completed SQL query before sending.
 			 *
 			 * @since 2.0.0
-			 * @since x.x.x This query now no longer contains a `SQL_CALC_FOUND_ROWS` modifier.
+			 * @since x.x.x This query no longer contains a `SQL_CALC_FOUND_ROWS` modifier by default.
 			 *
 			 * @param string   $request The complete SQL query.
 			 * @param WP_Query $query   The WP_Query instance (passed by reference).
 			 */
 			$this->request = apply_filters_ref_array( 'posts_request', array( $this->request, &$this ) );
+
+			if ( false !== strpos( $this->request, 'SQL_CALC_FOUND_ROWS' ) ) {
+				$this->use_calc_found_rows = true;
+				$this->request_count       = 'SELECT FOUND_ROWS()';
+			}
 		}
 
 		/**
@@ -3058,7 +3072,7 @@ public function get_posts() {
 			/** @var int[] */
 			$this->posts      = array_map( 'intval', $this->posts );
 			$this->post_count = count( $this->posts );
-			$this->limits     = $limits;
+			$this->set_limits( $limits );
 
 			return $this->posts;
 		}
@@ -3069,7 +3083,7 @@ public function get_posts() {
 			}
 
 			$this->post_count = count( $this->posts );
-			$this->limits     = $limits;
+			$this->set_limits( $limits );
 
 			/** @var int[] */
 			$r = array();
@@ -3120,14 +3134,15 @@ public function get_posts() {
 
 				if ( $ids ) {
 					$this->posts = $ids;
-					$this->limits = $limits;
+					$this->set_limits( $limits );
+
 					_prime_post_caches( $ids, $q['update_post_term_cache'], $q['update_post_meta_cache'] );
 				} else {
 					$this->posts = array();
 				}
 			} else {
 				$this->posts = $wpdb->get_results( $this->request );
-				$this->limits = $limits;
+				$this->set_limits( $limits );
 			}
 		}
 
@@ -3388,6 +3403,21 @@ private function set_found_posts() {
 		}
 	}
 
+	/**
+	 * Undocumented function
+	 *
+	 * @since x.x.x
+	 *
+	 * @param string $limits ...
+	 */
+	private function set_limits( $limits ) {
+		$this->limits = $limits;
+
+		if ( $this->use_calc_found_rows ) {
+			$this->set_found_posts();
+		}
+	}
+
 	/**
 	 * Set up the next post and iterate current post index.
 	 *
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 18e7eea7533bc..caac02492e114 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1144,6 +1144,7 @@ public function test_posts_are_counted_with_select_found_rows_when_query_include
 			)
 		);
 
+		// These results should now reflect the results for draft posts, as set by the filter
 		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
 		$this->assertSame( 10, $q->found_posts, self::get_count_message( $q ) );
 		$this->assertEquals( 5, $q->max_num_pages, self::get_count_message( $q ) );

From d27629bf7bf14047e1ee358621f24fe79ed4455e Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 22:52:10 +0100
Subject: [PATCH 38/71] Trigger a deprecated notice when a filter on
 `posts_request` returns a query containing `SQL_CALC_FOUND_ROWS`.

---
 src/wp-includes/class-wp-query.php | 2 ++
 tests/phpunit/tests/post/query.php | 1 +
 2 files changed, 3 insertions(+)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index e23c9cd7e2601..42d8a4a1220e0 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3041,6 +3041,8 @@ public function get_posts() {
 			$this->request = apply_filters_ref_array( 'posts_request', array( $this->request, &$this ) );
 
 			if ( false !== strpos( $this->request, 'SQL_CALC_FOUND_ROWS' ) ) {
+				_deprecated_argument( 'The posts_request filter', 'x.x.x', '...' );
+
 				$this->use_calc_found_rows = true;
 				$this->request_count       = 'SELECT FOUND_ROWS()';
 			}
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index caac02492e114..0548dcd76257e 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1112,6 +1112,7 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 
 	/**
 	 * @ticket 47280
+	 * @expectedDeprecated The posts_request filter
 	 */
 	public function test_posts_are_counted_with_select_found_rows_when_query_includes_sql_calc_found_rows() {
 		// Create five published posts.

From 492caf523149bd69420cd58bb6ddc0111332dd37 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 12 Jan 2022 22:53:35 +0100
Subject: [PATCH 39/71] Boop.

---
 tests/phpunit/tests/post/query.php | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 0548dcd76257e..8e782f8ed41d2 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1125,19 +1125,22 @@ public function test_posts_are_counted_with_select_found_rows_when_query_include
 			)
 		);
 
-		add_filter( 'posts_request', function( $request ) {
-			global $wpdb;
-
-			return "
-				SELECT SQL_CALC_FOUND_ROWS {$wpdb->posts}.ID
-				FROM {$wpdb->posts}
-				WHERE 1=1
-				AND {$wpdb->posts}.post_type = 'post'
-				AND {$wpdb->posts}.post_status = 'draft'
-				ORDER BY {$wpdb->posts}.post_date
-				DESC LIMIT 0, 2
-			";
-		} );
+		add_filter(
+			'posts_request',
+			function( $request ) {
+				global $wpdb;
+
+				return "
+					SELECT SQL_CALC_FOUND_ROWS {$wpdb->posts}.ID
+					FROM {$wpdb->posts}
+					WHERE 1=1
+					AND {$wpdb->posts}.post_type = 'post'
+					AND {$wpdb->posts}.post_status = 'draft'
+					ORDER BY {$wpdb->posts}.post_date
+					DESC LIMIT 0, 2
+				";
+			}
+		);
 
 		$q = new WP_Query(
 			array(

From 1c3df82a64059ea187a872ca9861313c0154f90c Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 19 Jan 2022 23:17:53 +0100
Subject: [PATCH 40/71] Add an explicit assertion for `FOUND_ROWS()`.

---
 tests/phpunit/tests/post/query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 8e782f8ed41d2..7a84c6f9cf9b7 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1149,12 +1149,12 @@ function( $request ) {
 		);
 
 		// These results should now reflect the results for draft posts, as set by the filter
+		$this->assertStringContainsString( 'SELECT FOUND_ROWS()', $q->request_count );
 		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
 		$this->assertSame( 10, $q->found_posts, self::get_count_message( $q ) );
 		$this->assertEquals( 5, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
-
 	public function dataFields() {
 		return array(
 			'posts'   => array(

From 759e8d85a88494b0ec49c37ef6d1fbb3adf09009 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 20 Jan 2022 12:17:33 +0100
Subject: [PATCH 41/71] Add a test for switching sites between the query and
 fetching the post count.

---
 tests/phpunit/tests/post/query.php | 35 ++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 7a84c6f9cf9b7..baa98cb056601 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1110,6 +1110,41 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @group ms-required
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_are_correct_when_switching_between_sites( $fields ) {
+		$blog = self::factory()->blog->create();
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+			)
+		);
+
+		// Switch to another site.
+		switch_to_blog( $blog );
+
+		// Count the posts from the original site. This works because the SQL query
+		// and its table names has already been formed during the original query.
+		$post_count = $q->post_count;
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		// Switch back.
+		restore_current_blog();
+
+		$this->assertSame( 2, $post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @expectedDeprecated The posts_request filter

From ceec5ff15f067fbbe33b4508d3c44825bf94b37f Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 20 Jan 2022 12:48:36 +0100
Subject: [PATCH 42/71] Coding standards.

---
 tests/phpunit/tests/post/query.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index baa98cb056601..feaa22e0c8606 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1133,8 +1133,8 @@ public function test_found_posts_are_correct_when_switching_between_sites( $fiel
 
 		// Count the posts from the original site. This works because the SQL query
 		// and its table names has already been formed during the original query.
-		$post_count = $q->post_count;
-		$found_posts = $q->found_posts;
+		$post_count    = $q->post_count;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		// Switch back.

From 26174be996cd46f1e99788b1dccfce6adaf921a8 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 20 Jan 2022 12:48:51 +0100
Subject: [PATCH 43/71] Add more tests for `no_found_rows`.

---
 tests/phpunit/tests/post/query.php | 68 ++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index feaa22e0c8606..a38e25308a1e4 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -840,6 +840,40 @@ public function test_found_posts_property_is_present_in_php_serialized_query( $f
 		$this->assertEquals( 3, $unserialized->max_num_pages );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_property_is_present_in_php_serialized_query_with_no_found_rows( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+				'no_found_rows'  => true,
+			)
+		);
+
+		$serialized = serialize( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = unserialize( $serialized );
+
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 0, $unserialized->found_posts );
+
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertSame( 0, $unserialized->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider dataFields
@@ -873,6 +907,40 @@ public function test_found_posts_property_is_present_in_json_serialized_query( $
 		$this->assertEquals( 3, $unserialized->max_num_pages );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_property_is_present_in_json_serialized_query_with_no_found_rows( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+				'no_found_rows'  => true,
+			)
+		);
+
+		$serialized = json_encode( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = json_decode( $serialized );
+
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 0, $unserialized->found_posts );
+
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertSame( 0, $unserialized->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider dataFields

From 241f805ccc741d898ef46e1008ccad40bd9d0273 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Fri, 28 Jan 2022 23:30:52 +0100
Subject: [PATCH 44/71] Allow the `found_posts` and `max_num_pages` properties
 to be set externally.

---
 src/wp-includes/class-wp-query.php | 37 +++++++++++++++++++++++-------
 tests/phpunit/tests/post/query.php | 30 ++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 42d8a4a1220e0..7bf646920a6c4 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -529,18 +529,18 @@ private function init_query_flags() {
 	 * @since 1.5.0
 	 */
 	public function init() {
-		unset( $this->posts );
-		unset( $this->query );
+		$this->posts = null;
+		$this->query = null;
 		$this->query_vars = array();
-		unset( $this->queried_object );
-		unset( $this->queried_object_id );
+		$this->queried_object = null;
+		$this->queried_object_id = null;
 		$this->post_count   = 0;
 		$this->current_post = -1;
 		$this->in_the_loop  = false;
-		unset( $this->request );
-		unset( $this->post );
-		unset( $this->comments );
-		unset( $this->comment );
+		$this->request = null;
+		$this->post = null;
+		$this->comments = null;
+		$this->comment = null;
 		$this->comment_count         = 0;
 		$this->current_comment       = -1;
 		$this->found_posts           = null;
@@ -3732,6 +3732,27 @@ public function __get( $name ) {
 		}
 	}
 
+	/**
+	 * Allows some private properties to be set.
+	 *
+	 * @since x.x.x
+	 *
+	 * @param string $name  Name of property to set.
+	 * @param mixed  $value Value to set.
+	 */
+	public function __set( $name, $value ) {
+		if ( 'found_posts' === $name || 'max_num_pages' === $name ) {
+			$this->$name = $value;
+			return;
+		}
+
+		// This allows third party code to set dynamic properties.
+		if ( ! property_exists( $this, $name ) ) {
+			$this->$name = $value;
+			return;
+		}
+	}
+
 	/**
 	 * Make private properties checkable for backward compatibility and lazy loading.
 	 *
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index a38e25308a1e4..808363185a886 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -807,6 +807,36 @@ public function test_found_posts_property_is_present_with_no_found_rows_true( $f
 		$this->assertNotNull( $q->max_num_pages );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_property_can_be_set_externally( $fields ) {
+		add_filter(
+			'posts_request',
+			function( $request, $query ) {
+				$query->found_posts   = 123;
+				$query->max_num_pages = 456;
+
+				return $request;
+			},
+			10,
+			2
+		);
+
+		$q = new WP_Query(
+			array(
+				'fields'    => $fields,
+				'post_type' => 'post',
+			)
+		);
+
+		$this->assertSame( 123, $q->found_posts );
+		$this->assertEquals( 456, $q->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider dataFields

From 1ab6b3aa39a26f6952db489ec1b5fb9306c5443b Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 29 Jan 2022 19:27:48 +0100
Subject: [PATCH 45/71] Rename this for clarity.

---
 src/wp-includes/class-wp-query.php | 8 ++++----
 tests/phpunit/tests/post/query.php | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 7bf646920a6c4..ae9ff02e0a010 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -89,7 +89,7 @@ class WP_Query implements JsonSerializable, Serializable {
 	 * @since xxx
 	 * @var string
 	 */
-	public $request_count;
+	public $count_request;
 
 	/**
 	 * Array of post objects or post IDs.
@@ -3026,7 +3026,7 @@ public function get_posts() {
 
 		$old_request   = "SELECT $distinct $fields FROM {$wpdb->posts} $join WHERE 1=1 $where $groupby $orderby $limits";
 		$this->request = $old_request;
-		$this->request_count = "SELECT COUNT($distinct {$wpdb->posts}.ID) FROM {$wpdb->posts} $join WHERE 1=1 $where";
+		$this->count_request = "SELECT COUNT($distinct {$wpdb->posts}.ID) FROM {$wpdb->posts} $join WHERE 1=1 $where";
 
 		if ( ! $q['suppress_filters'] ) {
 			/**
@@ -3044,7 +3044,7 @@ public function get_posts() {
 				_deprecated_argument( 'The posts_request filter', 'x.x.x', '...' );
 
 				$this->use_calc_found_rows = true;
-				$this->request_count       = 'SELECT FOUND_ROWS()';
+				$this->count_request       = 'SELECT FOUND_ROWS()';
 			}
 		}
 
@@ -3374,7 +3374,7 @@ private function set_found_posts() {
 			 * @param string   $found_posts_query The query to run to find the found posts.
 			 * @param WP_Query $query             The WP_Query instance (passed by reference).
 			 */
-			$found_posts_query = apply_filters_ref_array( 'found_posts_query', array( $this->request_count, &$this ) );
+			$found_posts_query = apply_filters_ref_array( 'found_posts_query', array( $this->count_request, &$this ) );
 
 			$this->found_posts = (int) $wpdb->get_var( $found_posts_query );
 		} else {
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 808363185a886..432b9e99e523b 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1282,7 +1282,7 @@ function( $request ) {
 		);
 
 		// These results should now reflect the results for draft posts, as set by the filter
-		$this->assertStringContainsString( 'SELECT FOUND_ROWS()', $q->request_count );
+		$this->assertStringContainsString( 'SELECT FOUND_ROWS()', $q->count_request );
 		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
 		$this->assertSame( 10, $q->found_posts, self::get_count_message( $q ) );
 		$this->assertEquals( 5, $q->max_num_pages, self::get_count_message( $q ) );
@@ -1306,7 +1306,7 @@ protected static function get_count_message( WP_Query $query ) {
 		return sprintf(
 			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
 			$query->request,
-			$query->request_count
+			$query->count_request
 		);
 	}
 

From 3a676788966505db759e03d0f7c988e8e5a7a3d7 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 30 Jan 2022 15:15:42 +0100
Subject: [PATCH 46/71] Apply some basic formatting to SQL queries during a
 test failure.

---
 tests/phpunit/tests/post/query.php | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 432b9e99e523b..7a147ba245a47 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1305,8 +1305,22 @@ public function dataFields() {
 	protected static function get_count_message( WP_Query $query ) {
 		return sprintf(
 			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",
-			$query->request,
-			$query->count_request
+			self::format_sql( $query->request ),
+			self::format_sql( $query->count_request )
+		);
+	}
+
+	/**
+	 * Applies some basic formatting to an SQL query to make it more readable during a test failure.
+	 *
+	 * @param string $sql
+	 * @return string
+	 */
+	protected static function format_sql( $sql ) {
+		return preg_replace(
+			'# (FROM|INNER JOIN|LEFT JOIN|ON|WHERE|AND|GROUP BY|ORDER BY|LIMIT) #',
+			"\n\$1 ",
+			$sql
 		);
 	}
 

From dd323a754fee1094d0248b2d20a102bddf626111 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 30 Jan 2022 17:04:07 +0100
Subject: [PATCH 47/71] Add a test for queries that trigger the
 `post_status_join` branch.

---
 tests/phpunit/tests/post/query.php | 42 ++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 7a147ba245a47..7ae0ec9fec5d1 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1153,6 +1153,48 @@ public function test_found_posts_are_correct_for_author_queries( $fields ) {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * A query for the following triggers an additional LEFT JOIN on `wp_posts`:
+	 *
+	 *  - Custom taxonomy query
+	 *  - `post_status` specified
+	 *  - `post_type` not specified
+	 *
+	 * @ticket 47280
+	 * @dataProvider dataFields
+	 *
+	 * @param string $fields
+	 */
+	public function test_found_posts_are_correct_for_query_that_performs_post_status_join( $fields ) {
+		$taxonomy = 'post_status_join_tax';
+		register_taxonomy( $taxonomy, 'post' );
+		$term = self::factory()->term->create_and_get(
+			array(
+				'taxonomy' => $taxonomy,
+			),
+		);
+		self::factory()->post->create_many( 5 );
+		$ids = self::factory()->post->create_many( 5 );
+
+		foreach ( $ids as $id ) {
+			wp_set_post_terms( $id, $term->slug, $taxonomy );
+		}
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'taxonomy'       => $taxonomy,
+				'term'           => $term->slug,
+				'post_status'    => 'publish',
+			)
+		);
+
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider dataFields

From 656a371ef37898bb0c94f53887b40c32f4c12640 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 30 Jan 2022 17:15:50 +0100
Subject: [PATCH 48/71] Syntax correction.

---
 tests/phpunit/tests/post/query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 7ae0ec9fec5d1..c61305757aa2b 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1171,7 +1171,7 @@ public function test_found_posts_are_correct_for_query_that_performs_post_status
 		$term = self::factory()->term->create_and_get(
 			array(
 				'taxonomy' => $taxonomy,
-			),
+			)
 		);
 		self::factory()->post->create_many( 5 );
 		$ids = self::factory()->post->create_many( 5 );

From 0a7325d80bf23d033d9845bc734eebde526df250 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 28 Mar 2022 22:55:37 +0200
Subject: [PATCH 49/71] Re-remove `SQL_CALC_FOUND_ROWS`.

---
 src/wp-includes/class-wp-query.php | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 70d2f4c68bfe5..39c74e54a39bd 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3024,13 +3024,8 @@ public function get_posts() {
 			$orderby = 'ORDER BY ' . $orderby;
 		}
 
-		$found_rows = '';
-		if ( ! $q['no_found_rows'] && ! empty( $limits ) ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS';
-		}
-
 		$old_request = "
-			SELECT $found_rows $distinct $fields
+			SELECT $distinct $fields
 			FROM {$wpdb->posts} $join
 			WHERE 1=1 $where
 			$groupby
@@ -3133,7 +3128,7 @@ public function get_posts() {
 				// First get the IDs and then fill in the objects.
 
 				$this->request = "
-					SELECT $found_rows $distinct {$wpdb->posts}.ID
+					SELECT $distinct {$wpdb->posts}.ID
 					FROM {$wpdb->posts} $join
 					WHERE 1=1 $where
 					$groupby

From 32e9bd305756148ca580cdecea3e96005f969d98 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 28 Mar 2022 22:04:32 +0100
Subject: [PATCH 50/71] Apply suggestions from code review

Co-authored-by: Colin Stewart <79332690+costdev@users.noreply.github.com>
---
 src/wp-includes/class-wp-user-query.php |  6 +++---
 tests/phpunit/tests/post/query.php      | 20 ++++++++++----------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/wp-includes/class-wp-user-query.php b/src/wp-includes/class-wp-user-query.php
index 89e122235d7c2..42ba79c07387a 100644
--- a/src/wp-includes/class-wp-user-query.php
+++ b/src/wp-includes/class-wp-user-query.php
@@ -784,9 +784,9 @@ public function query() {
 
 				/**
 				 * Return a total count of users.
-				 * Historically this ran SELECT FOUND_ROWS() after issuing the main query,
-				 * but since SQL_CALC_FOUND_ROWS is now deprecated from MySQL, it instead repeats
-				 * the same query with COUNT(*) instead of $this->query_fields.
+				 * Historically this ran `SELECT FOUND_ROWS()` after issuing the main query,
+				 * but since `SQL_CALC_FOUND_ROWS` is now deprecated from MySQL, it instead repeats
+				 * the same query with `COUNT(*)` instead of `$this->query_fields`.
 				 *
 				 * @since 3.2.0
 				 * @since 5.1.0 Added the `$this` parameter.
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index c61305757aa2b..9990d07ab89f0 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1001,25 +1001,25 @@ public function test_found_posts_should_be_lazily_loaded( $fields ) {
 		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
-		// Count the queries after fetching found posts
+		// Count the queries after fetching found posts.
 		$after_found_posts = ( $wpdb->num_queries - $start );
 
 		// Repeat
 		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
-		// Count the queries after fetching found posts a second time
+		// Count the queries after fetching found posts a second time.
 		$after_found_posts_again = ( $wpdb->num_queries - $start );
 
-		// Ensure the posts were not initially counted
+		// Ensure the posts were not initially counted.
 		$this->assertSame( 1, $before_found_posts );
 
-		// Ensure the counts are correct
+		// Ensure the counts are correct.
 		$this->assertSame( 2, $post_count );
 		$this->assertSame( 5, $found_posts );
 		$this->assertEquals( 3, $max_num_pages );
 
-		// Ensure subsequent counts only triggered one query
+		// Ensure subsequent counts only triggered one query.
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts );
 		$this->assertSame( ( $before_found_posts + 1 ), $after_found_posts_again );
 	}
@@ -1076,7 +1076,7 @@ public function test_found_posts_are_correct_for_query_with_no_limit( $fields )
 
 		$this->assertSame( 5, $q->post_count, self::get_count_message( $q ) );
 		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
-		// You would expect this to be 1 but historically it's 0 for posts without paging
+		// You would expect this to be 1 but historically it's 0 for posts without paging.
 		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
@@ -1098,7 +1098,7 @@ public function test_found_posts_are_correct_for_query_with_no_paging( $fields )
 
 		$this->assertSame( 5, $q->post_count, self::get_count_message( $q ) );
 		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
-		// You would expect this to be 1 but historically it's 0 for posts without paging
+		// You would expect this to be 1 but historically it's 0 for posts without paging.
 		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
@@ -1323,7 +1323,7 @@ function( $request ) {
 			)
 		);
 
-		// These results should now reflect the results for draft posts, as set by the filter
+		// These results should now reflect the results for draft posts, as set by the filter.
 		$this->assertStringContainsString( 'SELECT FOUND_ROWS()', $q->count_request );
 		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
 		$this->assertSame( 10, $q->found_posts, self::get_count_message( $q ) );
@@ -1355,8 +1355,8 @@ protected static function get_count_message( WP_Query $query ) {
 	/**
 	 * Applies some basic formatting to an SQL query to make it more readable during a test failure.
 	 *
-	 * @param string $sql
-	 * @return string
+	 * @param string $sql The SQL query to be formatted.
+	 * @return string     The formatted SQL query.
 	 */
 	protected static function format_sql( $sql ) {
 		return preg_replace(

From f24cb977f41055c503f960e922ab0850dd3e74e9 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 28 Mar 2022 23:07:00 +0200
Subject: [PATCH 51/71] Rename the fields data provider.

---
 tests/phpunit/tests/post/query.php | 36 +++++++++++++++---------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 9990d07ab89f0..129e12856f4aa 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -761,7 +761,7 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -785,7 +785,7 @@ public function test_found_posts_property_is_present_with_no_found_rows_false( $
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -809,7 +809,7 @@ public function test_found_posts_property_is_present_with_no_found_rows_true( $f
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -839,7 +839,7 @@ function( $request, $query ) {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -872,7 +872,7 @@ public function test_found_posts_property_is_present_in_php_serialized_query( $f
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -906,7 +906,7 @@ public function test_found_posts_property_is_present_in_php_serialized_query_wit
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -939,7 +939,7 @@ public function test_found_posts_property_is_present_in_json_serialized_query( $
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -973,7 +973,7 @@ public function test_found_posts_property_is_present_in_json_serialized_query_wi
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1039,7 +1039,7 @@ public function test_found_posts_are_correct_for_empty_query() {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1060,7 +1060,7 @@ public function test_found_posts_are_correct_for_basic_query( $fields ) {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1082,7 +1082,7 @@ public function test_found_posts_are_correct_for_query_with_no_limit( $fields )
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1104,7 +1104,7 @@ public function test_found_posts_are_correct_for_query_with_no_paging( $fields )
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1126,7 +1126,7 @@ public function test_found_posts_are_correct_for_paged_query( $fields ) {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1161,7 +1161,7 @@ public function test_found_posts_are_correct_for_author_queries( $fields ) {
 	 *  - `post_type` not specified
 	 *
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1197,7 +1197,7 @@ public function test_found_posts_are_correct_for_query_that_performs_post_status
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1225,7 +1225,7 @@ public function test_found_posts_are_correct_for_tax_queries( $fields ) {
 
 	/**
 	 * @ticket 47280
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1253,7 +1253,7 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 	/**
 	 * @ticket 47280
 	 * @group ms-required
-	 * @dataProvider dataFields
+	 * @dataProvider data_fields
 	 *
 	 * @param string $fields
 	 */
@@ -1330,7 +1330,7 @@ function( $request ) {
 		$this->assertEquals( 5, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
-	public function dataFields() {
+	public function data_fields() {
 		return array(
 			'posts'   => array(
 				'',

From 49b195ae57f48b293df1d29eceb753947c6bb725 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 28 Mar 2022 23:08:35 +0200
Subject: [PATCH 52/71] Use static closures.

---
 tests/phpunit/tests/post/query.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 129e12856f4aa..b08600f221b42 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -816,7 +816,7 @@ public function test_found_posts_property_is_present_with_no_found_rows_true( $f
 	public function test_found_posts_property_can_be_set_externally( $fields ) {
 		add_filter(
 			'posts_request',
-			function( $request, $query ) {
+			static function( $request, $query ) {
 				$query->found_posts   = 123;
 				$query->max_num_pages = 456;
 
@@ -1302,7 +1302,7 @@ public function test_posts_are_counted_with_select_found_rows_when_query_include
 
 		add_filter(
 			'posts_request',
-			function( $request ) {
+			static function( $request ) {
 				global $wpdb;
 
 				return "

From 85cba24b708fb7d97841e06cc1503e1a44ee9420 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Mon, 28 Mar 2022 23:12:44 +0200
Subject: [PATCH 53/71] Docs!

---
 tests/phpunit/tests/post/query.php | 45 +++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 17 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index b08600f221b42..c7d3a704ca9a5 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -763,7 +763,7 @@ public function test_found_posts_should_be_integer_even_if_found_posts_filter_re
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_is_present_with_no_found_rows_false( $fields ) {
 		$q = new WP_Query(
@@ -787,7 +787,7 @@ public function test_found_posts_property_is_present_with_no_found_rows_false( $
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_is_present_with_no_found_rows_true( $fields ) {
 		$q = new WP_Query(
@@ -811,7 +811,7 @@ public function test_found_posts_property_is_present_with_no_found_rows_true( $f
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_can_be_set_externally( $fields ) {
 		add_filter(
@@ -841,7 +841,7 @@ static function( $request, $query ) {
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_is_present_in_php_serialized_query( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -874,7 +874,7 @@ public function test_found_posts_property_is_present_in_php_serialized_query( $f
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_is_present_in_php_serialized_query_with_no_found_rows( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -908,7 +908,7 @@ public function test_found_posts_property_is_present_in_php_serialized_query_wit
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_is_present_in_json_serialized_query( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -941,7 +941,7 @@ public function test_found_posts_property_is_present_in_json_serialized_query( $
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_property_is_present_in_json_serialized_query_with_no_found_rows( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -975,7 +975,7 @@ public function test_found_posts_property_is_present_in_json_serialized_query_wi
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_should_be_lazily_loaded( $fields ) {
 		global $wpdb;
@@ -1041,7 +1041,7 @@ public function test_found_posts_are_correct_for_empty_query() {
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_basic_query( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -1062,7 +1062,7 @@ public function test_found_posts_are_correct_for_basic_query( $fields ) {
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_query_with_no_limit( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -1084,7 +1084,7 @@ public function test_found_posts_are_correct_for_query_with_no_limit( $fields )
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_query_with_no_paging( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -1106,7 +1106,7 @@ public function test_found_posts_are_correct_for_query_with_no_paging( $fields )
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_paged_query( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -1128,7 +1128,7 @@ public function test_found_posts_are_correct_for_paged_query( $fields ) {
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_author_queries( $fields ) {
 		$author = self::factory()->user->create();
@@ -1163,7 +1163,7 @@ public function test_found_posts_are_correct_for_author_queries( $fields ) {
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_query_that_performs_post_status_join( $fields ) {
 		$taxonomy = 'post_status_join_tax';
@@ -1199,7 +1199,7 @@ public function test_found_posts_are_correct_for_query_that_performs_post_status
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_tax_queries( $fields ) {
 		$term = self::factory()->term->create_and_get();
@@ -1227,7 +1227,7 @@ public function test_found_posts_are_correct_for_tax_queries( $fields ) {
 	 * @ticket 47280
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 		self::factory()->post->create_many( 5 );
@@ -1255,7 +1255,7 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 	 * @group ms-required
 	 * @dataProvider data_fields
 	 *
-	 * @param string $fields
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
 	public function test_found_posts_are_correct_when_switching_between_sites( $fields ) {
 		$blog = self::factory()->blog->create();
@@ -1330,6 +1330,11 @@ static function( $request ) {
 		$this->assertEquals( 5, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * Data provider for tests which need to run once for each possible value of the fields argument.
+	 *
+	 * @return array Test data.
+	 */
 	public function data_fields() {
 		return array(
 			'posts'   => array(
@@ -1344,6 +1349,12 @@ public function data_fields() {
 		);
 	}
 
+	/**
+	 * Helper method which returns a readable representation of the SQL queries performed.
+	 *
+	 * @param WP_Query $query The current query instance.
+	 * @return string The formatted message.
+	 */
 	protected static function get_count_message( WP_Query $query ) {
 		return sprintf(
 			"Request SQL:\n\n%s\n\nCount SQL:\n\n%s\n",

From 6ed6430422af0e1b05ffe1dde485adcd9ba2fa18 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 30 Mar 2022 00:30:41 +0200
Subject: [PATCH 54/71] Add a test for multiple meta queries.

---
 tests/phpunit/tests/post/query.php | 35 ++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index c7d3a704ca9a5..1c5b673e42476 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1250,6 +1250,41 @@ public function test_found_posts_are_correct_for_meta_queries( $fields ) {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_are_correct_for_multiple_meta_queries( $fields ) {
+		self::factory()->post->create_many( 5 );
+		$ids = self::factory()->post->create_many( 5 );
+
+		foreach ( $ids as $id ) {
+			add_post_meta( $id, 'field_1', 'foo' );
+			add_post_meta( $id, 'field_2', 'bar' );
+		}
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'meta_query'     => array(
+					array(
+						'key' => 'field_1',
+					),
+					array(
+						'key' => 'field_2',
+					),
+				),
+			)
+		);
+
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @group ms-required

From 2e2ccf7e0bf2a96a32fce05c04e8f5b19ca8bdc5 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 30 Mar 2022 00:42:01 +0200
Subject: [PATCH 55/71] Formatting.

---
 src/wp-includes/class-wp-query.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 39c74e54a39bd..14339413c6444 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3034,7 +3034,11 @@ public function get_posts() {
 		";
 
 		$this->request = $old_request;
-		$this->count_request = "SELECT COUNT($distinct {$wpdb->posts}.ID) FROM {$wpdb->posts} $join WHERE 1=1 $where";
+		$this->count_request = "
+			SELECT COUNT($distinct {$wpdb->posts}.ID)
+			FROM {$wpdb->posts} $join
+			WHERE 1=1 $where
+		";
 
 		if ( ! $q['suppress_filters'] ) {
 			/**

From b78e97bedd728348f3bb7bac0fb74ecbed0a0785 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 12:05:01 +0200
Subject: [PATCH 56/71] Implement the deprecated argument message for the
 `posts_request` filter.

---
 src/wp-includes/class-wp-query.php | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 14339413c6444..4443785aebeb8 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -86,7 +86,7 @@ class WP_Query implements JsonSerializable, Serializable {
 	/**
 	 * Get post database count query
 	 *
-	 * @since xxx
+	 * @since x.x.x
 	 * @var string
 	 */
 	public $count_request;
@@ -3053,7 +3053,16 @@ public function get_posts() {
 			$this->request = apply_filters_ref_array( 'posts_request', array( $this->request, &$this ) );
 
 			if ( false !== strpos( $this->request, 'SQL_CALC_FOUND_ROWS' ) ) {
-				_deprecated_argument( 'The posts_request filter', 'x.x.x', '...' );
+				_deprecated_argument(
+					'The posts_request filter',
+					'x.x.x',
+					sprintf(
+						/* translators: 1: SQL query modifier 2: SQL query */
+						__( 'The %1$s query modifier should no longer be added to queries because results are no longer counted with %2$s by default.' ),
+						'<code>SQL_CALC_FOUND_ROWS</code>',
+						'<code>SELECT FOUND_ROWS()</code>'
+					)
+				);
 
 				$this->use_calc_found_rows = true;
 				$this->count_request       = 'SELECT FOUND_ROWS()';

From 36bc0a6c79da95a7b9058791b6fe191a96ee4d5d Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 12:17:39 +0200
Subject: [PATCH 57/71] More docs.

---
 src/wp-includes/class-wp-query.php | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 4443785aebeb8..cffe4ed103d58 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -474,7 +474,7 @@ class WP_Query implements JsonSerializable, Serializable {
 	private $stopwords;
 
 	/**
-	 * Undocumented variable
+	 * The LIMIT clause of the query, used only during counting of results.
 	 *
 	 * @since x.x.x
 	 * @var string
@@ -3402,7 +3402,10 @@ private function set_found_posts() {
 			 * Filters the query to run for retrieving the found posts.
 			 *
 			 * @since 2.1.0
-			 * @since x.x.x This query was changed...
+			 * @since x.x.x This query was changed from `SELECT FOUND_ROWS()` to a more
+			 *              efficient `COUNT` query which only runs when the `found_posts`
+			 *              or `max_num_pages` properties are first accessed. This allows
+			 *              for lazy population of the result count.
 			 *
 			 * @param string   $found_posts_query The query to run to find the found posts.
 			 * @param WP_Query $query             The WP_Query instance (passed by reference).
@@ -3426,7 +3429,9 @@ private function set_found_posts() {
 		 * Filters the number of found posts for the query.
 		 *
 		 * @since 2.1.0
-		 * @since x.x.x This filter now only runs after the value is lazily loaded...
+		 * @since x.x.x By default this filter now only runs when the `found_posts` or
+		 *              `max_num_pages` properties are first accessed. This allows for
+		 *              lazy population of the result count.
 		 *
 		 * @param int      $found_posts The number of posts found.
 		 * @param WP_Query $query       The WP_Query instance (passed by reference).
@@ -3439,11 +3444,11 @@ private function set_found_posts() {
 	}
 
 	/**
-	 * Undocumented function
+	 * Stores the LIMIT clause of the query for later use.
 	 *
 	 * @since x.x.x
 	 *
-	 * @param string $limits ...
+	 * @param string $limits The LIMIT clause of the query.
 	 */
 	private function set_limits( $limits ) {
 		$this->limits = $limits;

From 146dc6b72175d47fb714186b63b0db0f53ce575a Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 12:46:15 +0100
Subject: [PATCH 58/71] Add a test that covers no results.

---
 tests/phpunit/tests/post/query.php | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 1c5b673e42476..1214912874536 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1037,6 +1037,25 @@ public function test_found_posts_are_correct_for_empty_query() {
 		$this->assertSame( 0, $q->max_num_pages );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_are_correct_for_query_with_no_results( $fields ) {
+		$q = new WP_Query(
+			array(
+				'fields'       => $fields,
+				'posts_status' => 'draft',
+			)
+		);
+
+		$this->assertSame( 0, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 0, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider data_fields

From 6ff250e55cab0c5401cfbc98afeb96c576a52592 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 12:59:18 +0100
Subject: [PATCH 59/71] Add a test that covers the value of the count
 properties when `no_found_rows` is true.

---
 tests/phpunit/tests/post/query.php | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 1214912874536..d8bcf87b70e1e 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1121,6 +1121,27 @@ public function test_found_posts_are_correct_for_query_with_no_paging( $fields )
 		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_are_correct_for_query_with_no_found_rows( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'        => $fields,
+				'no_found_rows' => true,
+			)
+		);
+
+		$this->assertSame( 5, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 0, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertSame( 0, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider data_fields

From 46e7466dff1863be55170e2c677f5b342f27908d Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 13:11:38 +0100
Subject: [PATCH 60/71] Better naming.

---
 tests/phpunit/tests/post/query.php | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index d8bcf87b70e1e..867fe4107d9a5 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -843,7 +843,7 @@ static function( $request, $query ) {
 	 *
 	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
-	public function test_found_posts_property_is_present_in_php_serialized_query( $fields ) {
+	public function test_found_posts_property_is_present_when_calculated_after_php_unserialization( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
@@ -876,7 +876,7 @@ public function test_found_posts_property_is_present_in_php_serialized_query( $f
 	 *
 	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
-	public function test_found_posts_property_is_present_in_php_serialized_query_with_no_found_rows( $fields ) {
+	public function test_found_posts_property_is_present_when_calculated_after_php_unserialization_with_no_found_rows( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
@@ -910,7 +910,7 @@ public function test_found_posts_property_is_present_in_php_serialized_query_wit
 	 *
 	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
-	public function test_found_posts_property_is_present_in_json_serialized_query( $fields ) {
+	public function test_found_posts_property_is_present_when_calculated_after_json_unserialization( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(
@@ -943,7 +943,7 @@ public function test_found_posts_property_is_present_in_json_serialized_query( $
 	 *
 	 * @param string $fields Value of the `fields` argument for `WP_Query`.
 	 */
-	public function test_found_posts_property_is_present_in_json_serialized_query_with_no_found_rows( $fields ) {
+	public function test_found_posts_property_is_present_when_calculated_after_json_unserialization_with_no_found_rows( $fields ) {
 		self::factory()->post->create_many( 5 );
 
 		$q = new WP_Query(

From 212e629b954ef8b41518ec7437e81c9d0817ded5 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 13:30:25 +0100
Subject: [PATCH 61/71] Add tests that cover fetching found rows before
 serialization.

---
 tests/phpunit/tests/post/query.php | 158 +++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 867fe4107d9a5..d933de194dceb 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -971,6 +971,164 @@ public function test_found_posts_property_is_present_when_calculated_after_json_
 		$this->assertSame( 0, $unserialized->max_num_pages );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_property_is_present_when_calculated_before_php_unserialization( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+			)
+		);
+
+		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		$serialized = serialize( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = unserialize( $serialized );
+
+		$this->assertSame( 5, $found_posts );
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 5, $unserialized->found_posts );
+
+		$this->assertEquals( 3, $max_num_pages );
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertEquals( 3, $unserialized->max_num_pages );
+	}
+
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_property_is_present_when_calculated_before_php_unserialization_with_no_found_rows( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+				'no_found_rows'  => true,
+			)
+		);
+
+		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		$serialized = serialize( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = unserialize( $serialized );
+
+		$this->assertSame( 0, $found_posts );
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 0, $unserialized->found_posts );
+
+		$this->assertSame( 0, $max_num_pages );
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertSame( 0, $unserialized->max_num_pages );
+	}
+
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_property_is_present_when_calculated_before_json_unserialization( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+			)
+		);
+
+		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		$serialized = json_encode( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = json_decode( $serialized );
+
+		$this->assertSame( 5, $found_posts );
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 5, $unserialized->found_posts );
+
+		$this->assertEquals( 3, $max_num_pages );
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertEquals( 3, $unserialized->max_num_pages );
+	}
+
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_property_is_present_when_calculated_before_json_unserialization_with_no_found_rows( $fields ) {
+		self::factory()->post->create_many( 5 );
+
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'post_type'      => 'post',
+				'no_found_rows'  => true,
+			)
+		);
+
+		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
+		$found_posts = $q->found_posts;
+		$max_num_pages = $q->max_num_pages;
+
+		$serialized = json_encode( $q );
+
+		// Create more matching posts to simulate unserialization occuring at a later date.
+		self::factory()->post->create_many( 5 );
+
+		$unserialized = json_decode( $serialized );
+
+		$this->assertSame( 0, $found_posts );
+		$this->assertTrue( property_exists( $unserialized, 'found_posts' ) );
+		$this->assertTrue( isset( $unserialized->found_posts ) );
+		$this->assertSame( 0, $unserialized->found_posts );
+
+		$this->assertSame( 0, $max_num_pages );
+		$this->assertTrue( property_exists( $unserialized, 'max_num_pages' ) );
+		$this->assertTrue( isset( $unserialized->max_num_pages ) );
+		$this->assertSame( 0, $unserialized->max_num_pages );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @dataProvider data_fields

From b4e0e5ae62a6813e6f1e1177af63dbe68322bbf2 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 13:33:39 +0100
Subject: [PATCH 62/71] =?UTF-8?q?=C2=AF\=5F(=E3=83=84)=5F/=C2=AF?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 tests/phpunit/tests/post/query.php | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index d933de194dceb..503e76b4ff186 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -989,7 +989,7 @@ public function test_found_posts_property_is_present_when_calculated_before_php_
 		);
 
 		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		$serialized = serialize( $q );
@@ -1029,7 +1029,7 @@ public function test_found_posts_property_is_present_when_calculated_before_php_
 		);
 
 		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		$serialized = serialize( $q );
@@ -1068,7 +1068,7 @@ public function test_found_posts_property_is_present_when_calculated_before_json
 		);
 
 		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		$serialized = json_encode( $q );
@@ -1108,7 +1108,7 @@ public function test_found_posts_property_is_present_when_calculated_before_json
 		);
 
 		// Fetch found_posts and max_num_pages here so the values are populated when serialized.
-		$found_posts = $q->found_posts;
+		$found_posts   = $q->found_posts;
 		$max_num_pages = $q->max_num_pages;
 
 		$serialized = json_encode( $q );

From df1db9d6095f85f58393296a913ee8bcb0b73415 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 20:54:54 +0100
Subject: [PATCH 63/71] Revert changes in other query classes for now to keep
 the `WP_Query` changes clean.

---
 src/wp-includes/class-wp-comment-query.php |  4 ++--
 src/wp-includes/class-wp-network-query.php |  4 ++--
 src/wp-includes/class-wp-site-query.php    |  4 ++--
 src/wp-includes/class-wp-user-query.php    | 13 +++++++------
 4 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/src/wp-includes/class-wp-comment-query.php b/src/wp-includes/class-wp-comment-query.php
index 11aba2f63e277..bf3db0ecf35b0 100644
--- a/src/wp-includes/class-wp-comment-query.php
+++ b/src/wp-includes/class-wp-comment-query.php
@@ -183,7 +183,7 @@ public function __call( $name, $arguments ) {
 	 *                                                      When used with `$offset`, `$offset` takes precedence. Default 1.
 	 *     @type int             $offset                    Number of comments to offset the query. Used to build
 	 *                                                      LIMIT clause. Default 0.
-	 *     @type bool            $no_found_rows             Whether to disable the query to count found rows.
+	 *     @type bool            $no_found_rows             Whether to disable the `SQL_CALC_FOUND_ROWS` query.
 	 *                                                      Default: true.
 	 *     @type string|array    $orderby                   Comment status or array of statuses. To use 'meta_value'
 	 *                                                      or 'meta_value_num', `$meta_key` must also be defined.
@@ -952,7 +952,7 @@ protected function get_comment_ids() {
 
 		$found_rows = '';
 		if ( ! $this->query_vars['no_found_rows'] ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS'; // @TODO
+			$found_rows = 'SQL_CALC_FOUND_ROWS';
 		}
 
 		$this->sql_clauses['select']  = "SELECT $found_rows $fields";
diff --git a/src/wp-includes/class-wp-network-query.php b/src/wp-includes/class-wp-network-query.php
index edad5f20bbf25..429143976ca04 100644
--- a/src/wp-includes/class-wp-network-query.php
+++ b/src/wp-includes/class-wp-network-query.php
@@ -98,7 +98,7 @@ class WP_Network_Query {
 	 *     @type int          $number               Maximum number of networks to retrieve. Default empty (no limit).
 	 *     @type int          $offset               Number of networks to offset the query. Used to build LIMIT clause.
 	 *                                              Default 0.
-	 *     @type bool         $no_found_rows        Whether to disable the query to count found rows. Default true.
+	 *     @type bool         $no_found_rows        Whether to disable the `SQL_CALC_FOUND_ROWS` query. Default true.
 	 *     @type string|array $orderby              Network status or array of statuses. Accepts 'id', 'domain', 'path',
 	 *                                              'domain_length', 'path_length' and 'network__in'. Also accepts false,
 	 *                                              an empty array, or 'none' to disable `ORDER BY` clause. Default 'id'.
@@ -471,7 +471,7 @@ protected function get_network_ids() {
 
 		$found_rows = '';
 		if ( ! $this->query_vars['no_found_rows'] ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS'; // @TODO
+			$found_rows = 'SQL_CALC_FOUND_ROWS';
 		}
 
 		$this->sql_clauses['select']  = "SELECT $found_rows $fields";
diff --git a/src/wp-includes/class-wp-site-query.php b/src/wp-includes/class-wp-site-query.php
index bf7b184362111..1a4df65d99dd4 100644
--- a/src/wp-includes/class-wp-site-query.php
+++ b/src/wp-includes/class-wp-site-query.php
@@ -127,7 +127,7 @@ class WP_Site_Query {
 	 *     @type int             $number                 Maximum number of sites to retrieve. Default 100.
 	 *     @type int             $offset                 Number of sites to offset the query. Used to build LIMIT clause.
 	 *                                                   Default 0.
-	 *     @type bool            $no_found_rows          Whether to disable the query to count found rows. Default true.
+	 *     @type bool            $no_found_rows          Whether to disable the `SQL_CALC_FOUND_ROWS` query. Default true.
 	 *     @type string|array    $orderby                Site status or array of statuses. Accepts:
 	 *                                                   - 'id'
 	 *                                                   - 'domain'
@@ -674,7 +674,7 @@ protected function get_site_ids() {
 
 		$found_rows = '';
 		if ( ! $this->query_vars['no_found_rows'] ) {
-			$found_rows = 'SQL_CALC_FOUND_ROWS'; // @TODO
+			$found_rows = 'SQL_CALC_FOUND_ROWS';
 		}
 
 		$this->sql_clauses['select']  = "SELECT $found_rows $fields";
diff --git a/src/wp-includes/class-wp-user-query.php b/src/wp-includes/class-wp-user-query.php
index 42ba79c07387a..a757e38e20969 100644
--- a/src/wp-includes/class-wp-user-query.php
+++ b/src/wp-includes/class-wp-user-query.php
@@ -289,6 +289,10 @@ public function prepare_query( $query = array() ) {
 			$this->query_fields = "$wpdb->users.ID";
 		}
 
+		if ( isset( $qv['count_total'] ) && $qv['count_total'] ) {
+			$this->query_fields = 'SQL_CALC_FOUND_ROWS ' . $this->query_fields;
+		}
+
 		$this->query_from  = "FROM $wpdb->users";
 		$this->query_where = 'WHERE 1=1';
 
@@ -781,12 +785,8 @@ public function query() {
 			}
 
 			if ( isset( $qv['count_total'] ) && $qv['count_total'] ) {
-
 				/**
-				 * Return a total count of users.
-				 * Historically this ran `SELECT FOUND_ROWS()` after issuing the main query,
-				 * but since `SQL_CALC_FOUND_ROWS` is now deprecated from MySQL, it instead repeats
-				 * the same query with `COUNT(*)` instead of `$this->query_fields`.
+				 * Filters SELECT FOUND_ROWS() query for the current WP_User_Query instance.
 				 *
 				 * @since 3.2.0
 				 * @since 5.1.0 Added the `$this` parameter.
@@ -796,7 +796,8 @@ public function query() {
 				 * @param string        $sql   The SELECT FOUND_ROWS() query for the current WP_User_Query.
 				 * @param WP_User_Query $query The current WP_User_Query instance.
 				 */
-				$found_users_query = apply_filters( 'found_users_query', "SELECT COUNT(*) $this->query_from $this->query_where", $this );
+				$found_users_query = apply_filters( 'found_users_query', 'SELECT FOUND_ROWS()', $this );
+
 				$this->total_users = (int) $wpdb->get_var( $found_users_query );
 			}
 		}

From e7623ed0e74bb5cd8af79c87bb1c0872fc0d4539 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sat, 2 Apr 2022 20:54:59 +0100
Subject: [PATCH 64/71] More docs.

---
 src/wp-includes/class-wp-query.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index cffe4ed103d58..032ab2801de04 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -189,7 +189,9 @@ class WP_Query implements JsonSerializable, Serializable {
 	private $max_num_pages = 0;
 
 	/**
-	 * Undocumented variable
+	 * Whether the SQL query to count the results should use `SQL_CALC_FOUND_ROWS`.
+	 *
+	 * Used only as a fallback if a filter on the main query reinstates `SELECT FOUND_ROWS()`.
 	 *
 	 * @since x.x.x
 	 *

From 3041fde071824a08fde675f6e203d25719e02632 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Thu, 23 Jun 2022 21:33:26 +0100
Subject: [PATCH 65/71] More tidying up of SQL in test failure messages.

---
 tests/phpunit/tests/post/query.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 503e76b4ff186..3d1d4f0751966 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1603,11 +1603,14 @@ protected static function get_count_message( WP_Query $query ) {
 	 * @return string     The formatted SQL query.
 	 */
 	protected static function format_sql( $sql ) {
-		return preg_replace(
+		$sql = preg_replace(
 			'# (FROM|INNER JOIN|LEFT JOIN|ON|WHERE|AND|GROUP BY|ORDER BY|LIMIT) #',
 			"\n\$1 ",
 			$sql
 		);
+		$sql = preg_replace( '#^\t+#m', '', $sql );
+
+		return $sql;
 	}
 
 }

From 5ad1aff534ad0f31727ef2622b577ef50b94ce92 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 3 Jul 2022 01:45:14 +0100
Subject: [PATCH 66/71] This can be null too.

---
 src/wp-includes/class-wp-query.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index a5c1b24747bda..0ee6e7a831401 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -174,7 +174,7 @@ class WP_Query implements JsonSerializable, Serializable {
 	 * @since 2.1.0
 	 * @since x.x.x This value is now lazily loaded only when it's needed.
 	 *
-	 * @var int
+	 * @var int|null
 	 */
 	private $found_posts = null;
 

From 47f5c6fd79cb13bc2f7348f65e9e16d2d6c1784b Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 14 Aug 2022 01:56:47 +0100
Subject: [PATCH 67/71] Always count distinct post IDs. This ensures the count
 for meta queries with an `OR` relationship is accurate.

---
 src/wp-includes/class-wp-query.php |  2 +-
 tests/phpunit/tests/post/query.php | 41 ++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 74bab1a194317..5eed0ac25bb41 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3068,7 +3068,7 @@ public function get_posts() {
 
 		$this->request = $old_request;
 		$this->count_request = "
-			SELECT COUNT($distinct {$wpdb->posts}.ID)
+			SELECT COUNT(DISTINCT {$wpdb->posts}.ID)
 			FROM {$wpdb->posts} $join
 			WHERE 1=1 $where
 		";
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 3d1d4f0751966..97bb91109a5f5 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1483,6 +1483,47 @@ public function test_found_posts_are_correct_for_multiple_meta_queries( $fields
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_are_correct_for_OR_meta_queries( $fields ) {
+		self::factory()->post->create_many( 5 );
+		$ids = self::factory()->post->create_many( 5 );
+
+		// Add a mixture of meta values so all 5 posts match the meta query.
+		add_post_meta( $ids[0], 'field_1', 'foo' );
+		add_post_meta( $ids[0], 'field_2', 'bar' );
+		add_post_meta( $ids[1], 'field_1', 'foo' );
+		add_post_meta( $ids[2], 'field_1', 'foo' );
+		add_post_meta( $ids[3], 'field_2', 'bar' );
+		add_post_meta( $ids[4], 'field_2', 'bar' );
+
+		// This query results in a `GROUP BY wp_posts.ID` clause, which means the
+		// count query must count DISTINCT post IDs to eliminate duplicate posts.
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+				'meta_query'     => array(
+					'relation' => 'OR',
+					array(
+						'key' => 'field_1',
+					),
+					array(
+						'key' => 'field_2',
+					),
+				),
+			)
+		);
+
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		$this->assertSame( 5, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @group ms-required

From b9bddc4dd5073235e13709f4ff816fdc5802de39 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 14 Aug 2022 02:16:16 +0100
Subject: [PATCH 68/71] Account for a custom `GROUP BY` field or fields.

---
 src/wp-includes/class-wp-query.php |  5 +++-
 tests/phpunit/tests/post/query.php | 47 +++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 5eed0ac25bb41..8290c578d758a 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3050,7 +3050,10 @@ public function get_posts() {
 			$limits   = isset( $clauses['limits'] ) ? $clauses['limits'] : '';
 		}
 
+		$count_field = "{$wpdb->posts}.ID";
+
 		if ( ! empty( $groupby ) ) {
+			$count_field = $groupby;
 			$groupby = 'GROUP BY ' . $groupby;
 		}
 		if ( ! empty( $orderby ) ) {
@@ -3068,7 +3071,7 @@ public function get_posts() {
 
 		$this->request = $old_request;
 		$this->count_request = "
-			SELECT COUNT(DISTINCT {$wpdb->posts}.ID)
+			SELECT COUNT(DISTINCT {$count_field})
 			FROM {$wpdb->posts} $join
 			WHERE 1=1 $where
 		";
diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 97bb91109a5f5..3a6782550a6d0 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1502,7 +1502,7 @@ public function test_found_posts_are_correct_for_OR_meta_queries( $fields ) {
 		add_post_meta( $ids[4], 'field_2', 'bar' );
 
 		// This query results in a `GROUP BY wp_posts.ID` clause, which means the
-		// count query must count DISTINCT post IDs to eliminate duplicate posts.
+		// count query must count `DISTINCT wp_posts.ID` to eliminate duplicates.
 		$q = new WP_Query(
 			array(
 				'fields'         => $fields,
@@ -1524,6 +1524,51 @@ public function test_found_posts_are_correct_for_OR_meta_queries( $fields ) {
 		$this->assertEquals( 3, $q->max_num_pages, self::get_count_message( $q ) );
 	}
 
+	/**
+	 * @ticket 47280
+	 * @dataProvider data_fields
+	 *
+	 * @param string $fields Value of the `fields` argument for `WP_Query`.
+	 */
+	public function test_found_posts_are_correct_for_group_by_queries( $fields ) {
+		$user1 = self::factory()->user->create();
+		$user2 = self::factory()->user->create();
+
+		self::factory()->post->create_many(
+			5,
+			array(
+				'post_author' => $user1,
+			)
+		);
+		self::factory()->post->create_many(
+			5,
+			array(
+				'post_author' => $user2,
+			)
+		);
+
+		/**
+		 * Adds a GROUP BY clause to the query.
+		 */
+		add_filter( 'posts_groupby_request', function() {
+			return "{$GLOBALS['wpdb']->posts}.post_author";
+		} );
+
+		// This query results in a `GROUP BY wp_posts.post_author` clause, which means the
+		// count query must count `DISTINCT wp_posts.post_author` to eliminate duplicates.
+		$q = new WP_Query(
+			array(
+				'fields'         => $fields,
+				'posts_per_page' => 2,
+			)
+		);
+
+		$this->assertSame( 2, $q->post_count, self::get_count_message( $q ) );
+		// There is a total of two distinct authors in the results.
+		$this->assertSame( 2, $q->found_posts, self::get_count_message( $q ) );
+		$this->assertEquals( 1, $q->max_num_pages, self::get_count_message( $q ) );
+	}
+
 	/**
 	 * @ticket 47280
 	 * @group ms-required

From abe2176f01a5b88c8561bc6fb7024bc9edb6a3f4 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 14 Aug 2022 02:19:03 +0100
Subject: [PATCH 69/71] Coding standards.

---
 src/wp-includes/class-wp-query.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index 8290c578d758a..1bb3dca12bfbc 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -3054,6 +3054,7 @@ public function get_posts() {
 
 		if ( ! empty( $groupby ) ) {
 			$count_field = $groupby;
+
 			$groupby = 'GROUP BY ' . $groupby;
 		}
 		if ( ! empty( $orderby ) ) {

From bbedca0c3a6dc61995320b568029aa0dbf1cbf00 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Sun, 14 Aug 2022 02:26:04 +0100
Subject: [PATCH 70/71] My coding is not up to standards.

---
 tests/phpunit/tests/post/query.php | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tests/phpunit/tests/post/query.php b/tests/phpunit/tests/post/query.php
index 3a6782550a6d0..4f748ac03920c 100644
--- a/tests/phpunit/tests/post/query.php
+++ b/tests/phpunit/tests/post/query.php
@@ -1550,9 +1550,12 @@ public function test_found_posts_are_correct_for_group_by_queries( $fields ) {
 		/**
 		 * Adds a GROUP BY clause to the query.
 		 */
-		add_filter( 'posts_groupby_request', function() {
-			return "{$GLOBALS['wpdb']->posts}.post_author";
-		} );
+		add_filter(
+			'posts_groupby_request',
+			function() {
+				return "{$GLOBALS['wpdb']->posts}.post_author";
+			}
+		);
 
 		// This query results in a `GROUP BY wp_posts.post_author` clause, which means the
 		// count query must count `DISTINCT wp_posts.post_author` to eliminate duplicates.

From d537eabea2878787acfa9f5d63c4f83e1730ee67 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@gmail.com>
Date: Wed, 18 Jan 2023 11:18:25 +0000
Subject: [PATCH 71/71] Avoid a deprecated error in PHP 8.1.

---
 src/wp-includes/class-wp-query.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/wp-includes/class-wp-query.php b/src/wp-includes/class-wp-query.php
index b970eb461a42f..b1d75838682c9 100644
--- a/src/wp-includes/class-wp-query.php
+++ b/src/wp-includes/class-wp-query.php
@@ -4099,6 +4099,7 @@ public function __unserialize( $data ) { // phpcs:ignore PHPCompatibility.Functi
 	 *
 	 * @return array The properties of the object as an associative array.
 	 */
+	#[ReturnTypeWillChange]
 	public function jsonSerialize() {
 		$this->set_found_posts();