Store null index filters

Fixes #20136

Author: AndriySvyryd

src/EFCore.Relational/Extensions/RelationalIndexExtensions.cs

@@ -86,7 +86,7 @@ public static string GetFilter([NotNull] this IIndex index)
         /// <param name="index"> The index. </param>
         /// <param name="value"> The value to set. </param>
         public static void SetFilter([NotNull] this IMutableIndex index, [CanBeNull] string value)
-            => index.SetOrRemoveAnnotation(
+            => index.SetAnnotation(
                 RelationalAnnotationNames.Filter,
                 Check.NullButNotEmpty(value, nameof(value)));
 
@@ -97,7 +97,7 @@ public static void SetFilter([NotNull] this IMutableIndex index, [CanBeNull] str
         /// <param name="value"> The value to set. </param>
         /// <param name="fromDataAnnotation"> Indicates whether the configuration was specified using a data annotation. </param>
         public static void SetFilter([NotNull] this IConventionIndex index, [CanBeNull] string value, bool fromDataAnnotation = false)
-            => index.SetOrRemoveAnnotation(
+            => index.SetAnnotation(
                 RelationalAnnotationNames.Filter,
                 Check.NullButNotEmpty(value, nameof(value)),
                 fromDataAnnotation);

test/EFCore.Relational.Tests/Metadata/RelationalMetadataBuilderExtensionsTest.cs

@@ -155,6 +155,27 @@ public void Can_access_index()
 
             Assert.Null(indexBuilder.HasName("Splod"));
             Assert.Equal("Splow", indexBuilder.Metadata.GetName());
+
+            Assert.NotNull(indexBuilder.HasName(null, fromDataAnnotation: true));
+            Assert.Equal("IX_Splot_Id", indexBuilder.Metadata.GetName());
+
+            Assert.NotNull(indexBuilder.HasName("Splod"));
+            Assert.Equal("Splod", indexBuilder.Metadata.GetName());
+
+            Assert.NotNull(indexBuilder.HasFilter("Splew"));
+            Assert.Equal("Splew", indexBuilder.Metadata.GetFilter());
+
+            Assert.NotNull(indexBuilder.HasFilter("Splow", fromDataAnnotation: true));
+            Assert.Equal("Splow", indexBuilder.Metadata.GetFilter());
+
+            Assert.Null(indexBuilder.HasFilter("Splod"));
+            Assert.Equal("Splow", indexBuilder.Metadata.GetFilter());
+
+            Assert.NotNull(indexBuilder.HasFilter(null, fromDataAnnotation: true));
+            Assert.Null(indexBuilder.Metadata.GetFilter());
+
+            Assert.Null(indexBuilder.HasFilter("Splod"));
+            Assert.Null(indexBuilder.Metadata.GetFilter());
         }
 
         [ConditionalFact]

test/EFCore.Relational.Tests/Metadata/RelationalMetadataExtensionsTest.cs

@@ -42,17 +42,17 @@ public void Can_get_and_set_index_filter()
         {
             var modelBuilder = new ModelBuilder(new ConventionSet());
 
-            var property = modelBuilder
+            var index = modelBuilder
                 .Entity<Customer>()
                 .HasIndex(e => e.Id)
                 .HasFilter("[Id] % 2 = 0")
                 .Metadata;
 
-            Assert.Equal("[Id] % 2 = 0", property.GetFilter());
+            Assert.Equal("[Id] % 2 = 0", index.GetFilter());
 
-            property.SetFilter("[Id] % 3 = 0");
+            index.SetFilter("[Id] % 3 = 0");
 
-            Assert.Equal("[Id] % 3 = 0", property.GetFilter());
+            Assert.Equal("[Id] % 3 = 0", index.GetFilter());
         }
 
         [ConditionalFact]