Small: Report cross-document join exception on Cosmos, and some test cleanup

src/EFCore.Cosmos/Properties/CosmosStrings.resx

@@ -135,6 +135,9 @@
   <data name="CosmosNotInUse" xml:space="preserve">
     <value>Cosmos-specific methods can only be used when the context is using the Cosmos provider.</value>
   </data>
+  <data name="CrossDocumentJoinNotSupported" xml:space="preserve">
+    <value>Joins across documents aren't supported in Cosmos; consider modeling your data differently so that related data is in the same document. Alternatively, perform two separate queries to query the two documents.</value>
+  </data>
   <data name="DefaultTTLMismatch" xml:space="preserve">
     <value>The default time to live was configured to '{ttl1}' on '{entityType1}', but on '{entityType2}' it was configured to '{ttl2}'. All entity types mapped to the same container '{container}' must be configured with the same default time to live.</value>
   </data>

src/EFCore.Cosmos/Query/Internal/CosmosQueryableMethodTranslatingExpressionVisitor.cs

@@ -762,7 +762,10 @@ protected override ShapedQueryExpression TranslateDistinct(ShapedQueryExpression
         LambdaExpression outerKeySelector,
         LambdaExpression innerKeySelector,
         LambdaExpression resultSelector)
-        => null;
+    {
+        AddTranslationErrorDetails(CosmosStrings.CrossDocumentJoinNotSupported);
+        return null;
+    }
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -807,7 +810,10 @@ protected override ShapedQueryExpression TranslateDistinct(ShapedQueryExpression
         LambdaExpression outerKeySelector,
         LambdaExpression innerKeySelector,
         LambdaExpression resultSelector)
-        => null;
+    {
+        AddTranslationErrorDetails(CosmosStrings.CrossDocumentJoinNotSupported);
+        return null;
+    }
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to

test/EFCore.Cosmos.FunctionalTests/Query/OwnedQueryCosmosTest.cs

@@ -17,9 +17,11 @@ public OwnedQueryCosmosTest(OwnedQueryCosmosFixture fixture, ITestOutputHelper t
         Fixture.TestSqlLoggerFactory.SetTestOutputHelper(testOutputHelper);
     }
 
-    // TODO: Fake LeftJoin, #33969
+    // Fink.Barton is a non-owned navigation, cross-document join
     public override Task Query_loads_reference_nav_automatically_in_projection(bool async)
-        => AssertTranslationFailed(() => base.Query_loads_reference_nav_automatically_in_projection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Query_loads_reference_nav_automatically_in_projection(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
     // Non-correlated queries not supported by Cosmos
     public override Task Query_with_owned_entity_equality_operator(bool async)
@@ -161,10 +163,11 @@ FROM root c
 """);
             });
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Filter_owned_entity_chained_with_regular_entity_followed_by_projecting_owned_collection(bool async)
-        => AssertTranslationFailed(
-            () => base.Filter_owned_entity_chained_with_regular_entity_followed_by_projecting_owned_collection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Filter_owned_entity_chained_with_regular_entity_followed_by_projecting_owned_collection(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
     public override async Task Set_throws_for_owned_type(bool async)
     {
@@ -173,55 +176,65 @@ public override async Task Set_throws_for_owned_type(bool async)
         AssertSql();
     }
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_filter(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_filter(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference_and_scalar(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference_and_scalar(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference_and_scalar(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_collection(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_collection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_collection(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_collection_count(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_collection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_collection_count(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_property(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_property(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_property(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference_in_predicate_and_projection(bool async)
-        => AssertTranslationFailed(
-            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference_in_predicate_and_projection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity_and_another_reference_in_predicate_and_projection(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Project_multiple_owned_navigations(bool async)
-        => AssertTranslationFailed(
-            () => base.Project_multiple_owned_navigations(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Project_multiple_owned_navigations(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task Project_multiple_owned_navigations_with_expansion_on_owned_collections(bool async)
-        => AssertTranslationFailed(
-            () => base.Project_multiple_owned_navigations_with_expansion_on_owned_collections(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.Project_multiple_owned_navigations_with_expansion_on_owned_collections(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]
@@ -240,13 +253,38 @@ JOIN a IN c["Orders"]
 """);
             });
 
-    // TODO: Fake LeftJoin, #33969
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public override Task SelectMany_with_result_selector(bool async)
+        => CosmosTestHelpers.Instance.NoSyncTest(
+            async, async a =>
+            {
+                await base.SelectMany_with_result_selector(a);
+
+                AssertSql(
+                    """
+SELECT VALUE
+{
+    "PersonId" : c["Id"],
+    "OrderId" : a["Id"]
+}
+FROM root c
+JOIN a IN c["Orders"]
+WHERE c["Discriminator"] IN ("OwnedPerson", "Branch", "LeafB", "LeafA")
+""");
+            });
+
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task SelectMany_on_owned_reference_followed_by_regular_entity_and_collection(bool async)
-        => AssertTranslationFailed(() => base.SelectMany_on_owned_reference_followed_by_regular_entity_and_collection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.SelectMany_on_owned_reference_followed_by_regular_entity_and_collection(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
-    // TODO: Fake LeftJoin, #33969
+    // Address.Planet is a non-owned navigation, cross-document join
     public override Task SelectMany_on_owned_reference_with_entity_in_between_ending_in_owned_collection(bool async)
-        => AssertTranslationFailed(() => base.SelectMany_on_owned_reference_with_entity_in_between_ending_in_owned_collection(async));
+        => AssertTranslationFailedWithDetails(
+            () => base.SelectMany_on_owned_reference_with_entity_in_between_ending_in_owned_collection(async),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
     // Non-correlated queries not supported by Cosmos
     public override Task Query_with_owned_entity_equality_method(bool async)
@@ -274,6 +312,32 @@ FROM root c
     public override Task Query_when_subquery(bool async)
         => AssertTranslationFailed(() => base.Query_when_subquery(async));
 
+    public override Task Project_owned_reference_navigation_which_owns_additional(bool async)
+        => CosmosTestHelpers.Instance.NoSyncTest(
+            async, async a =>
+            {
+                await base.Project_owned_reference_navigation_which_owns_additional(a);
+
+                // TODO: The following should project out c["PersonAddress"], not c: #34067
+                AssertSql(
+                    """
+SELECT c
+FROM root c
+WHERE c["Discriminator"] IN ("OwnedPerson", "Branch", "LeafB", "LeafA")
+ORDER BY c["Id"]
+""");
+            });
+
+    // TODO: #34068
+    public override async Task Project_owned_reference_navigation_which_does_not_own_additional(bool async)
+    {
+        // Always throws for sync.
+        if (async)
+        {
+            await Assert.ThrowsAsync<NullReferenceException>(() => base.Project_owned_reference_navigation_which_does_not_own_additional(async));
+        }
+    }
+
     public override Task No_ignored_include_warning_when_implicit_load(bool async)
         => CosmosTestHelpers.Instance.NoSyncTest(
             async, async a =>
@@ -320,6 +384,7 @@ await AssertQuery(
                     assertOrder: true,
                     elementAsserter: (e, a) => AssertCollection(e, a));
 
+                // TODO: The following should project out a["Details"], not a: #34067
                 AssertSql(
                     """
 SELECT a
@@ -687,12 +752,13 @@ public override async Task NoTracking_Include_with_cycles_throws(bool async)
         AssertSql();
     }
 
-    // TODO: Fake LeftJoin, #33969
+    // Order.Client is a non-owned navigation, cross-document join
     public override Task NoTracking_Include_with_cycles_does_not_throw_when_performing_identity_resolution(
         bool async,
         bool useAsTracking)
-        => AssertTranslationFailed(
-            () => base.NoTracking_Include_with_cycles_does_not_throw_when_performing_identity_resolution(async, useAsTracking));
+        => AssertTranslationFailedWithDetails(
+            () => base.NoTracking_Include_with_cycles_does_not_throw_when_performing_identity_resolution(async, useAsTracking),
+            CosmosStrings.CrossDocumentJoinNotSupported);
 
     public override async Task Trying_to_access_non_existent_indexer_property_throws_meaningful_exception(bool async)
     {

test/EFCore.Specification.Tests/Query/OwnedQueryTestBase.cs

@@ -130,6 +130,20 @@ public virtual Task Query_when_subquery(bool async)
             assertOrder: true,
             elementAsserter: (e, a) => AssertEqual(e.op, a.op));
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task Project_owned_reference_navigation_which_owns_additional(bool async)
+        => AssertQuery(
+            async,
+            ss => ss.Set<OwnedPerson>().OrderBy(o => o.Id).Select(p => p.PersonAddress));
+
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task Project_owned_reference_navigation_which_does_not_own_additional(bool async)
+        => AssertQuery(
+            async,
+            ss => ss.Set<OwnedPerson>().OrderBy(o => o.Id).Select(p => p.PersonAddress.Country));
+
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]
     public virtual Task Navigation_rewrite_on_owned_reference_projecting_scalar(bool async)
@@ -177,6 +191,13 @@ public virtual Task SelectMany_on_owned_collection(bool async)
             async,
             ss => ss.Set<OwnedPerson>().SelectMany(p => p.Orders));
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task SelectMany_with_result_selector(bool async)
+        => AssertQuery(
+            async,
+            ss => ss.Set<OwnedPerson>().SelectMany(o => o.Orders, (p, o) => new { PersonId = p.Id, OrderId = o.Id }));
+
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]
     public virtual async Task Set_throws_for_owned_type(bool async)

test/EFCore.SqlServer.FunctionalTests/Query/OwnedQuerySqlServerTest.cs

@@ -191,6 +191,30 @@ FROM [Order] AS [o1]
 """);
     }
 
+    public override async Task Project_owned_reference_navigation_which_owns_additional(bool async)
+    {
+        await base.Project_owned_reference_navigation_which_owns_additional(async);
+
+        AssertSql(
+            """
+SELECT [o].[Id], [o].[PersonAddress_AddressLine], [o].[PersonAddress_PlaceType], [o].[PersonAddress_ZipCode], [o].[PersonAddress_Country_Name], [o].[PersonAddress_Country_PlanetId]
+FROM [OwnedPerson] AS [o]
+ORDER BY [o].[Id]
+""");
+    }
+
+    public override async Task Project_owned_reference_navigation_which_does_not_own_additional(bool async)
+    {
+        await base.Project_owned_reference_navigation_which_does_not_own_additional(async);
+
+        AssertSql(
+            """
+SELECT [o].[Id], [o].[PersonAddress_Country_Name], [o].[PersonAddress_Country_PlanetId]
+FROM [OwnedPerson] AS [o]
+ORDER BY [o].[Id]
+""");
+    }
+
     public override async Task Navigation_rewrite_on_owned_reference_projecting_scalar(bool async)
     {
         await base.Navigation_rewrite_on_owned_reference_projecting_scalar(async);
@@ -291,6 +315,18 @@ FROM [OwnedPerson] AS [o]
 """);
     }
 
+    public override async Task SelectMany_with_result_selector(bool async)
+    {
+        await base.SelectMany_with_result_selector(async);
+
+        AssertSql(
+            """
+SELECT [o].[Id] AS [PersonId], [o0].[Id] AS [OrderId]
+FROM [OwnedPerson] AS [o]
+INNER JOIN [Order] AS [o0] ON [o].[Id] = [o0].[ClientId]
+""");
+    }
+
     public override async Task Navigation_rewrite_on_owned_reference_followed_by_regular_entity(bool async)
     {
         await base.Navigation_rewrite_on_owned_reference_followed_by_regular_entity(async);