Fix backslash character stripping in Copy Post module

projects/plugins/jetpack/changelog/fix-copy-post-backslash-stripping

@@ -0,0 +1,4 @@
+Significance: patch
+Type: bugfix
+
+Copy Post: Fix issue where backslash characters were being stripped from post content when duplicating a post.

projects/plugins/jetpack/modules/copy-post.php

@@ -168,7 +168,9 @@ protected function update_content( $source_post, $target_post_id ) {
 		 * @param int     $target_post_id Target post ID.
 		 */
 		$data = apply_filters( 'jetpack_copy_post_data', $data, $source_post, $target_post_id );
-		return wp_update_post( $data );
+		// wp_update_post expects slashed data (like from $_POST) and internally calls wp_unslash,
+		// so we need to slash the data first to preserve backslash characters in the content.
+		return wp_update_post( wp_slash( $data ) );
 	}
 
 	/**

projects/plugins/jetpack/phpunit.11.xml.dist

@@ -45,6 +45,9 @@
 		<testsuite name="comment-likes">
 			<directory suffix="Test.php">tests/php/modules/comment-likes</directory>
 		</testsuite>
+		<testsuite name="copy-post">
+			<directory suffix="Test.php">tests/php/modules/copy-post</directory>
+		</testsuite>
 		<testsuite name="likes">
 			<directory suffix="Test.php">tests/php/modules/likes</directory>
 		</testsuite>

projects/plugins/jetpack/phpunit.9.xml.dist

@@ -36,6 +36,9 @@
 		<testsuite name="comment-likes">
 			<directory suffix="Test.php">tests/php/modules/comment-likes</directory>
 		</testsuite>
+		<testsuite name="copy-post">
+			<directory suffix="Test.php">tests/php/modules/copy-post</directory>
+		</testsuite>
 		<testsuite name="likes">
 			<directory suffix="Test.php">tests/php/modules/likes</directory>
 		</testsuite>

projects/plugins/jetpack/tests/php/modules/copy-post/Copy_Post_Test.php

@@ -0,0 +1,213 @@
+<?php
+/**
+ * Tests for the Jetpack_Copy_Post class.
+ *
+ * @package automattic/jetpack
+ */
+
+use PHPUnit\Framework\Attributes\DataProvider;
+
+require_once JETPACK__PLUGIN_DIR . 'modules/copy-post.php';
+
+/**
+ * Test class for Jetpack_Copy_Post.
+ */
+class Copy_Post_Test extends WP_UnitTestCase {
+	use \Automattic\Jetpack\PHPUnit\WP_UnitTestCase_Fix;
+
+	/**
+	 * Test user ID.
+	 *
+	 * @var int
+	 */
+	private $user_id;
+
+	/**
+	 * Set up.
+	 */
+	public function set_up() {
+		parent::set_up();
+
+		// Create an admin user for testing.
+		$this->user_id = $this->factory->user->create( array( 'role' => 'administrator' ) );
+		wp_set_current_user( $this->user_id );
+	}
+
+	/**
+	 * Data provider for testing content with backslashes.
+	 *
+	 * @return array
+	 */
+	public static function data_content_with_backslashes() {
+		return array(
+			'tab escape sequence'         => array(
+				'<!-- wp:code --><pre class="wp-block-code"><code>\t is a tab</code></pre><!-- /wp:code -->',
+			),
+			'newline escape sequence'     => array(
+				'<!-- wp:code --><pre class="wp-block-code"><code>\n is a newline</code></pre><!-- /wp:code -->',
+			),
+			'form feed escape sequence'   => array(
+				'<!-- wp:code --><pre class="wp-block-code"><code>\f is a form feed</code></pre><!-- /wp:code -->',
+			),
+			'double backslash'            => array(
+				'<!-- wp:code --><pre class="wp-block-code"><code>\\\\ becomes \\</code></pre><!-- /wp:code -->',
+			),
+			'backslash with number'       => array(
+				'<!-- wp:code --><pre class="wp-block-code"><code>\\9 is backslash 9</code></pre><!-- /wp:code -->',
+			),
+			'backslash with space'        => array(
+				'<!-- wp:code --><pre class="wp-block-code"><code>\\ followed by space</code></pre><!-- /wp:code -->',
+			),
+			'multiple backslashes'        => array(
+				'<!-- wp:paragraph --><p>Text with \\t and \\n and \\f sequences</p><!-- /wp:paragraph -->',
+			),
+			'paragraph with backslash'    => array(
+				'<!-- wp:paragraph --><p>Simple \\t text</p><!-- /wp:paragraph -->',
+			),
+			'mixed content with backslashes' => array(
+				"<!-- wp:paragraph --><p>Path: C:\\\\Users\\\\test</p><!-- /wp:paragraph -->\n<!-- wp:code --><pre class=\"wp-block-code\"><code>echo \"\\n\";</code></pre><!-- /wp:code -->",
+			),
+		);
+	}
+
+	/**
+	 * Test that backslash characters are preserved when copying post content.
+	 *
+	 * @dataProvider data_content_with_backslashes
+	 *
+	 * @param string $content Post content to test.
+	 */
+	#[DataProvider( 'data_content_with_backslashes' )]
+	public function test_backslashes_preserved_in_content( $content ) {
+		// Create a source post with the content containing backslashes.
+		$source_post_id = $this->factory->post->create(
+			array(
+				'post_content' => $content,
+				'post_title'   => 'Test Post with Backslashes',
+				'post_status'  => 'draft',
+			)
+		);
+
+		$source_post = get_post( $source_post_id );
+
+		// Create a target post.
+		$target_post_id = $this->factory->post->create(
+			array(
+				'post_content' => '',
+				'post_title'   => '',
+				'post_status'  => 'auto-draft',
+			)
+		);
+
+		// Create an instance of Jetpack_Copy_Post and use reflection to call the protected update_content method.
+		$copy_post = new Jetpack_Copy_Post();
+
+		$reflection = new ReflectionClass( $copy_post );
+		$method     = $reflection->getMethod( 'update_content' );
+		$method->setAccessible( true );
+
+		// Call update_content.
+		$result = $method->invoke( $copy_post, $source_post, $target_post_id );
+
+		// Verify the result is successful.
+		$this->assertGreaterThan( 0, $result, 'wp_update_post should return a post ID on success' );
+
+		// Get the updated target post.
+		$updated_post = get_post( $target_post_id );
+
+		// Assert that the backslashes are preserved in the copied content.
+		$this->assertEquals(
+			$content,
+			$updated_post->post_content,
+			'Backslash characters should be preserved in copied content'
+		);
+	}
+
+	/**
+	 * Test that backslash characters are preserved in post titles.
+	 */
+	public function test_backslashes_preserved_in_title() {
+		$title = 'Title with \\t and \\n characters';
+
+		// Create a source post with a title containing backslashes.
+		$source_post_id = $this->factory->post->create(
+			array(
+				'post_content' => 'Some content',
+				'post_title'   => $title,
+				'post_status'  => 'draft',
+			)
+		);
+
+		$source_post = get_post( $source_post_id );
+
+		// Create a target post.
+		$target_post_id = $this->factory->post->create(
+			array(
+				'post_content' => '',
+				'post_title'   => '',
+				'post_status'  => 'auto-draft',
+			)
+		);
+
+		$copy_post = new Jetpack_Copy_Post();
+
+		$reflection = new ReflectionClass( $copy_post );
+		$method     = $reflection->getMethod( 'update_content' );
+		$method->setAccessible( true );
+
+		$method->invoke( $copy_post, $source_post, $target_post_id );
+
+		$updated_post = get_post( $target_post_id );
+
+		$this->assertEquals(
+			$title,
+			$updated_post->post_title,
+			'Backslash characters should be preserved in copied title'
+		);
+	}
+
+	/**
+	 * Test that backslash characters are preserved in post excerpts.
+	 */
+	public function test_backslashes_preserved_in_excerpt() {
+		$excerpt = 'Excerpt with \\t tab and \\n newline';
+
+		// Create a source post with an excerpt containing backslashes.
+		$source_post_id = $this->factory->post->create(
+			array(
+				'post_content' => 'Some content',
+				'post_title'   => 'Test Title',
+				'post_excerpt' => $excerpt,
+				'post_status'  => 'draft',
+			)
+		);
+
+		$source_post = get_post( $source_post_id );
+
+		// Create a target post.
+		$target_post_id = $this->factory->post->create(
+			array(
+				'post_content' => '',
+				'post_title'   => '',
+				'post_excerpt' => '',
+				'post_status'  => 'auto-draft',
+			)
+		);
+
+		$copy_post = new Jetpack_Copy_Post();
+
+		$reflection = new ReflectionClass( $copy_post );
+		$method     = $reflection->getMethod( 'update_content' );
+		$method->setAccessible( true );
+
+		$method->invoke( $copy_post, $source_post, $target_post_id );
+
+		$updated_post = get_post( $target_post_id );
+
+		$this->assertEquals(
+			$excerpt,
+			$updated_post->post_excerpt,
+			'Backslash characters should be preserved in copied excerpt'
+		);
+	}
+}