[release/7.0] Handle entity paths with no tables in model differ (#30394)

* Handle entity paths with no tables in model differ (#30347)

* Add quirk

Author: ajcvickers

src/EFCore.Relational/Migrations/Internal/MigrationsModelDiffer.cs

@@ -19,6 +19,9 @@ public class MigrationsModelDiffer : IMigrationsModelDiffer
     private static readonly bool QuirkEnabled27504
         = AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue27504", out var enabled) && enabled;
 
+    private static readonly bool UseOldBehavior30321
+        = AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue30321", out var enabled) && enabled;
+
     private static readonly Type[] DropOperationTypes =
     {
         typeof(DropIndexOperation),
@@ -939,11 +942,14 @@ private static bool ColumnStructureEquals(IColumn source, IColumn target)
 
     private static bool EntityTypePathEquals(IEntityType source, IEntityType target, DiffContext diffContext)
     {
-        var sourceTable = diffContext.GetTable(source);
-        var targetTable = diffContext.GetTable(target);
+        var sourceTable = diffContext.FindTable(source);
+        var targetTable = diffContext.FindTable(target);
 
-        if (sourceTable.EntityTypeMappings.Count() == 1
-            && targetTable.EntityTypeMappings.Count() == 1)
+        if ((!UseOldBehavior30321
+                && sourceTable == null
+                && targetTable == null)
+            || (sourceTable?.EntityTypeMappings.Count() == 1
+                && targetTable?.EntityTypeMappings.Count() == 1))
         {
             return true;
         }
@@ -953,8 +959,8 @@ private static bool EntityTypePathEquals(IEntityType source, IEntityType target,
             return false;
         }
 
-        var nextSource = sourceTable.GetRowInternalForeignKeys(source).FirstOrDefault()?.PrincipalEntityType;
-        var nextTarget = targetTable.GetRowInternalForeignKeys(target).FirstOrDefault()?.PrincipalEntityType;
+        var nextSource = sourceTable?.GetRowInternalForeignKeys(source).FirstOrDefault()?.PrincipalEntityType;
+        var nextTarget = targetTable?.GetRowInternalForeignKeys(target).FirstOrDefault()?.PrincipalEntityType;
         return (nextSource == null && nextTarget == null)
             || (nextSource != null
                 && nextTarget != null
@@ -1516,7 +1522,7 @@ protected virtual IEnumerable<MigrationOperation> Diff(
             Diff,
             Add,
             Remove,
-            (s, t, c) => c.GetTable(s.EntityType) == c.FindSource(c.GetTable(t.EntityType))
+            (s, t, c) => c.FindTable(s.EntityType) == c.FindSource(c.FindTable(t.EntityType))
                 && string.Equals(s.Name, t.Name, StringComparison.OrdinalIgnoreCase)
                 && string.Equals(s.Sql, t.Sql, StringComparison.OrdinalIgnoreCase));
 
@@ -2563,8 +2569,8 @@ public virtual void AddDrop(IColumn source, DropColumnOperation operation)
         ///     any release. You should only use it directly in your code with extreme caution and knowing that
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
-        public virtual ITable GetTable(IEntityType entityType)
-            => entityType.GetTableMappings().First().Table;
+        public virtual ITable? FindTable(IEntityType entityType)
+            => entityType.GetTableMappings().FirstOrDefault()?.Table;
 
         /// <summary>
         ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to

test/EFCore.SqlServer.Tests/Migrations/SqlServerModelDifferTest.cs

@@ -250,6 +250,146 @@ public void Alter_column_computation()
                 Assert.Equal("CAST(CURRENT_TIMESTAMP AS int)", operation.ComputedColumnSql);
             });
 
+    [ConditionalFact] // Issue #30321
+    public void Rename_column_TPC()
+        => Execute(
+            source =>
+            {
+                source.Entity(
+                    "Campaign",
+                    x =>
+                    {
+                        x.ToTable((string)null);
+                        x.UseTpcMappingStrategy();
+                        x.Property<int>("Id");
+                        x.Property<int>("Status");
+                    });
+
+                source.Entity(
+                    "SearchCampaign",
+                    x =>
+                    {
+                        x.HasBaseType("Campaign");
+                    });
+            },
+            source =>
+            {
+            },
+            target =>
+            {
+                target.Entity(
+                    "Campaign",
+                    x =>
+                    {
+                        x.Property<int>("Status").HasColumnName("status_new");
+                    });
+            },
+            operations =>
+            {
+                Assert.Equal(1, operations.Count);
+
+                var operation = Assert.IsType<RenameColumnOperation>(operations[0]);
+                Assert.Null(operation.Schema);
+                Assert.Equal("SearchCampaign", operation.Table);
+                Assert.Equal("Status", operation.Name);
+                Assert.Equal("status_new", operation.NewName);
+            });
+
+    [ConditionalFact]
+    public void Rename_column_TPT()
+        => Execute(
+            source =>
+            {
+                source.Entity(
+                    "Campaign",
+                    x =>
+                    {
+                        x.UseTptMappingStrategy();
+                        x.Property<int>("Id");
+                        x.Property<int>("Status");
+                    });
+
+                source.Entity(
+                    "SearchCampaign",
+                    x =>
+                    {
+                        x.HasBaseType("Campaign");
+                    });
+            },
+            source =>
+            {
+            },
+            target =>
+            {
+                target.Entity(
+                    "Campaign",
+                    x =>
+                    {
+                        x.Property<int>("Status").HasColumnName("status_new");
+                    });
+            },
+            operations =>
+            {
+                Assert.Equal(1, operations.Count);
+
+                var operation = Assert.IsType<RenameColumnOperation>(operations[0]);
+                Assert.Null(operation.Schema);
+                Assert.Equal("Campaign", operation.Table);
+                Assert.Equal("Status", operation.Name);
+                Assert.Equal("status_new", operation.NewName);
+            });
+
+
+    [ConditionalFact]
+    public void Rename_column_TPC_non_abstract()
+        => Execute(
+            source =>
+            {
+                source.Entity(
+                    "Campaign",
+                    x =>
+                    {
+                        x.UseTpcMappingStrategy();
+                        x.Property<int>("Id");
+                        x.Property<int>("Status");
+                    });
+
+                source.Entity(
+                    "SearchCampaign",
+                    x =>
+                    {
+                        x.HasBaseType("Campaign");
+                    });
+            },
+            source =>
+            {
+            },
+            target =>
+            {
+                target.Entity(
+                    "Campaign",
+                    x =>
+                    {
+                        x.Property<int>("Status").HasColumnName("status_new");
+                    });
+            },
+            operations =>
+            {
+                Assert.Equal(2, operations.Count);
+
+                var operation = Assert.IsType<RenameColumnOperation>(operations[0]);
+                Assert.Null(operation.Schema);
+                Assert.Equal("SearchCampaign", operation.Table);
+                Assert.Equal("Status", operation.Name);
+                Assert.Equal("status_new", operation.NewName);
+
+                operation = Assert.IsType<RenameColumnOperation>(operations[1]);
+                Assert.Null(operation.Schema);
+                Assert.Equal("Campaign", operation.Table);
+                Assert.Equal("Status", operation.Name);
+                Assert.Equal("status_new", operation.NewName);
+            });
+
     [ConditionalFact]
     public void Alter_primary_key_clustering()
         => Execute(