Copy instead of reusing the same reference in AnnotatableBase.AddAnnotations

Fixes #24658

Author: AndriySvyryd

Diff for: src/EFCore/Infrastructure/AnnotatableBase.cs

@@ -105,7 +105,7 @@ internal static void AddAnnotations(AnnotatableBase annotatable, IEnumerable<IAn
         {
             foreach (var annotation in annotations)
             {
-                annotatable.AddAnnotation(annotation.Name, (Annotation)annotation);
+                annotatable.AddAnnotation(annotation.Name, annotation.Value);
             }
         }
 
@@ -429,7 +429,7 @@ public virtual TValue GetOrAddRuntimeAnnotationValue<TValue, TArg>(
         /// <param name="value"> The value to be stored in the annotation. </param>
         /// <returns> The newly created annotation. </returns>
         protected virtual Annotation CreateRuntimeAnnotation(string name, object? value)
-            => new Annotation(name, value);
+            => new (name, value);
 
         private ConcurrentDictionary<string, Annotation> GetOrCreateRuntimeAnnotations()
         {

Diff for: test/EFCore.Specification.Tests/ManyToManyTrackingTestBase.cs

@@ -3708,7 +3708,7 @@ void ValidateFixup(DbContext context, IList<EntityOne> leftEntities, IList<Entit
                 Assert.Equal(3, context.ChangeTracker.Entries<EntityOne>().Count());
                 Assert.Equal(3, context.ChangeTracker.Entries<EntityTwo>().Count());
                 Assert.Equal(5, context.ChangeTracker.Entries<JoinOneToTwo>().Count());
-                Assert.Equal(1, context.ChangeTracker.Entries<JoinOneToTwoExtra>().Count());
+                Assert.Single(context.ChangeTracker.Entries<JoinOneToTwoExtra>());
 
                 Assert.Equal(3, leftEntities[0].TwoSkip.Count);
                 Assert.Single(leftEntities[1].TwoSkip);

Diff for: test/EFCore.Tests/Infrastructure/AnnotatableTest.cs

@@ -36,6 +36,22 @@ public void Can_add_and_remove_annotation()
             Assert.Null(annotatable.FindAnnotation("Foo"));
         }
 
+        [ConditionalFact]
+        public void Added_annotation_type_is_consistent()
+        {
+            var annotatable = new Annotatable();
+
+            annotatable.AddAnnotations(new[] { new ConventionAnnotation("Foo", "Bar", ConfigurationSource.Convention) });
+
+            Assert.Equal(typeof(Annotation), annotatable.FindAnnotation("Foo").GetType());
+
+            var conventionAnnotatable = new Model();
+
+            conventionAnnotatable.AddAnnotations(new[] { new Annotation("Foo", "Bar") });
+
+            Assert.Equal(typeof(ConventionAnnotation), conventionAnnotatable.FindAnnotation("Foo").GetType());
+        }
+
         [ConditionalFact]
         public void Adding_duplicate_annotation_throws()
         {