Allow to remove an index filter.

Add tests for the index filters Fluent API.

src/EFCore.Relational/Migrations/MigrationsSqlGenerator.cs

@@ -295,7 +295,7 @@ namespace Microsoft.EntityFrameworkCore.Migrations
                 .Append(ColumnList(operation.Columns))
                 .Append(")");
 
-            if (operation.Filter != null)
+            if (!string.IsNullOrEmpty(operation.Filter))
             {
                 builder
                     .Append(" WHERE ")

src/EFCore.Relational/RelationalIndexBuilderExtensions.cs

@@ -37,10 +37,8 @@ namespace Microsoft.EntityFrameworkCore
         /// <param name="indexBuilder"> The builder for the index being configured. </param>
         /// <param name="sql"> The filter expression for the index. </param>
         /// <returns>A builder to further configure the index. </returns>
-        public static IndexBuilder HasFilter([NotNull] this IndexBuilder indexBuilder, [NotNull] string sql)
+        public static IndexBuilder HasFilter([NotNull] this IndexBuilder indexBuilder, [CanBeNull] string sql)
         {
-            Check.NotEmpty(sql, nameof(sql));
-
             indexBuilder.Metadata.Relational().Filter = sql;
 
             return indexBuilder;

test/EFCore.Relational.Tests/ModelBuilderTest/RelationalTestModelBuilderExtensions.cs

@@ -1,32 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using Microsoft.EntityFrameworkCore.Infrastructure;
-using Microsoft.EntityFrameworkCore.Metadata.Builders;
-
-namespace Microsoft.EntityFrameworkCore.ModelBuilderTest
-{
-    public static class RelationalTestModelBuilderExtensions
-    {
-        public static ModelBuilding.ModelBuilderTest.TestPropertyBuilder<TProperty> HasColumnName<TProperty>(
-            this ModelBuilding.ModelBuilderTest.TestPropertyBuilder<TProperty> builder, string name)
-        {
-            var genericBuilder = (builder as IInfrastructure<PropertyBuilder<TProperty>>)?.Instance;
-
-            genericBuilder?.HasColumnName(name);
-
-            return builder;
-        }
-
-        public static ModelBuilding.ModelBuilderTest.TestReferenceOwnershipBuilder<TEntity, TRelatedEntity> ToTable<TEntity, TRelatedEntity>(
-            this ModelBuilding.ModelBuilderTest.TestReferenceOwnershipBuilder<TEntity, TRelatedEntity> builder, string name)
-            where TEntity : class
-            where TRelatedEntity : class
-        {
-            var genericBuilder = (builder as IInfrastructure<ReferenceOwnershipBuilder<TEntity, TRelatedEntity>>)?.Instance;
-            genericBuilder?.ToTable(name);
-
-            return builder;
-        }
-    }
-}

test/EFCore.Relational.Tests/ModelBuilding/RelationalTestModelBuilderExtensions.cs

@@ -0,0 +1,52 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace Microsoft.EntityFrameworkCore.ModelBuilding
+{
+    public static class RelationalTestModelBuilderExtensions
+    {
+        public static ModelBuilderTest.TestPropertyBuilder<TProperty> HasColumnName<TProperty>(
+            this ModelBuilderTest.TestPropertyBuilder<TProperty> builder, string name)
+        {
+            var genericBuilder = (builder as IInfrastructure<PropertyBuilder<TProperty>>)?.Instance;
+            if (genericBuilder != null)
+            {
+                genericBuilder.HasColumnName(name);
+            }
+            else
+            {
+                (builder as IInfrastructure<PropertyBuilder>).Instance.HasColumnName(name);
+            }
+
+            return builder;
+        }
+
+        public static ModelBuilderTest.TestReferenceOwnershipBuilder<TEntity, TRelatedEntity> ToTable<TEntity, TRelatedEntity>(
+            this ModelBuilderTest.TestReferenceOwnershipBuilder<TEntity, TRelatedEntity> builder, string name)
+            where TEntity : class
+            where TRelatedEntity : class
+        {
+            var genericBuilder = (builder as IInfrastructure<ReferenceOwnershipBuilder<TEntity, TRelatedEntity>>)?.Instance;
+            if (genericBuilder != null)
+            {
+                genericBuilder.ToTable(name);
+            }
+            else
+            {
+                (builder as IInfrastructure<ReferenceOwnershipBuilder>).Instance.ToTable(name);
+            }
+            return builder;
+        }
+
+        public static ModelBuilderTest.TestIndexBuilder HasFilter(
+            this ModelBuilderTest.TestIndexBuilder builder, string filterExpression)
+        {
+            var indexBuilder = builder.GetInfrastructure();
+            indexBuilder.HasFilter(filterExpression);
+            return builder;
+        }
+    }
+}

test/EFCore.SqlServer.Tests/ModelBuilding/SqlServerModelBuilderGenericTest.cs

@@ -4,7 +4,6 @@
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.EntityFrameworkCore.Metadata;
-using Microsoft.EntityFrameworkCore.ModelBuilderTest;
 using Xunit;
 
 namespace Microsoft.EntityFrameworkCore.ModelBuilding
@@ -62,6 +61,14 @@ namespace Microsoft.EntityFrameworkCore.ModelBuilding
                 entityTypeBuilder.Property(e => e.Name).HasColumnName(null);
 
                 Assert.Equal("[Name] IS NOT NULL", index.SqlServer().Filter);
+
+                indexBuilder.HasFilter("Foo");
+
+                Assert.Equal("Foo", index.SqlServer().Filter);
+
+                indexBuilder.HasFilter(null);
+
+                Assert.Null(index.SqlServer().Filter);
             }
 
             protected override TestModelBuilder CreateModelBuilder()

test/EFCore.Tests/ModelBuilding/ModelBuilderNonGenericTest.cs

@@ -168,7 +168,7 @@ namespace Microsoft.EntityFrameworkCore.ModelBuilding
                 => Wrap(EntityTypeBuilder.UsePropertyAccessMode(propertyAccessMode));
         }
 
-        protected class NonGenericTestPropertyBuilder<TProperty> : TestPropertyBuilder<TProperty>
+        protected class NonGenericTestPropertyBuilder<TProperty> : TestPropertyBuilder<TProperty>, IInfrastructure<PropertyBuilder>
         {
             public NonGenericTestPropertyBuilder(PropertyBuilder propertyBuilder)
             {
@@ -223,6 +223,8 @@ namespace Microsoft.EntityFrameworkCore.ModelBuilding
 
             public override TestPropertyBuilder<TProperty> UsePropertyAccessMode(PropertyAccessMode propertyAccessMode)
                 => new NonGenericTestPropertyBuilder<TProperty>(PropertyBuilder.UsePropertyAccessMode(propertyAccessMode));
+
+            PropertyBuilder IInfrastructure<PropertyBuilder>.Instance => PropertyBuilder;
         }
 
         protected class NonGenericTestReferenceNavigationBuilder<TEntity, TRelatedEntity> : TestReferenceNavigationBuilder<TEntity, TRelatedEntity>
@@ -340,7 +342,7 @@ namespace Microsoft.EntityFrameworkCore.ModelBuilding
         }
 
         protected class NonGenericTestReferenceOwnershipBuilder<TEntity, TRelatedEntity>
-            : TestReferenceOwnershipBuilder<TEntity, TRelatedEntity>
+            : TestReferenceOwnershipBuilder<TEntity, TRelatedEntity>, IInfrastructure<ReferenceOwnershipBuilder>
             where TEntity : class
             where TRelatedEntity : class
         {
@@ -439,6 +441,8 @@ namespace Microsoft.EntityFrameworkCore.ModelBuilding
             public override TestReferenceOwnershipBuilder<TEntity, TRelatedEntity> UsePropertyAccessMode(
                 PropertyAccessMode propertyAccessMode)
                 => Wrap<TEntity, TRelatedEntity>(ReferenceOwnershipBuilder.UsePropertyAccessMode(propertyAccessMode));
+
+            ReferenceOwnershipBuilder IInfrastructure<ReferenceOwnershipBuilder>.Instance => ReferenceOwnershipBuilder;
         }
     }
 }