Fix #30072 : Add Generic version of EntityTypeConfiguration Attribute

src/EFCore.Abstractions/EntityTypeConfigurationAttribute.cs

@@ -13,7 +13,7 @@ namespace Microsoft.EntityFrameworkCore;
 ///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see> for more information and examples.
 /// </remarks>
 [AttributeUsage(AttributeTargets.Class)]
-public sealed class EntityTypeConfigurationAttribute : Attribute
+public class EntityTypeConfigurationAttribute : Attribute
 {
     /// <summary>
     ///     Initializes a new instance of the <see cref="EntityTypeConfigurationAttribute" /> class.
@@ -32,3 +32,6 @@ public EntityTypeConfigurationAttribute(Type entityConfigurationType)
     [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor | DynamicallyAccessedMemberTypes.Interfaces)]
     public Type EntityTypeConfigurationType { get; }
 }
+
+
+

src/EFCore/EntityTypeConfigurationAttribute.cs

@@ -0,0 +1,24 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore;
+
+/// <summary>
+///     Specifies the configuration type for the entity type.
+/// </summary>
+/// <remarks>
+///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see> for more information and examples.
+/// </remarks>
+/// <typeparam name="TConfiguration">The IEntityTypeConfiguration&lt;&gt; type to use.</typeparam>
+/// <typeparam name="TEntity">The entity type to be configured.</typeparam>
+[AttributeUsage(AttributeTargets.Class)]
+public sealed class EntityTypeConfigurationAttribute<TConfiguration, TEntity> : EntityTypeConfigurationAttribute
+where TConfiguration : class , IEntityTypeConfiguration<TEntity>
+where TEntity : class
+{
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="EntityTypeConfigurationAttribute" /> class.
+    /// </summary>
+    public EntityTypeConfigurationAttribute() : base(typeof(TConfiguration)) { }
+
+}

test/EFCore.Tests/Metadata/Conventions/EntityTypeConfigurationAttributeConventionTest.cs

@@ -18,6 +18,17 @@ public void EntityTypeConfigurationAttribute_should_apply_configuration_to_Entit
         Assert.Equal(1000, entityType.FindProperty(nameof(Customer.Name)).GetMaxLength());
     }
 
+    [ConditionalFact]
+    public void EntityTypeConfigurationAttribute_should_apply_configuration_to_EntityType_Generic()
+    {
+        var builder = InMemoryTestHelpers.Instance.CreateConventionBuilder();
+
+        builder.Entity<CustomerGeneric>();
+
+        var entityType = builder.Model.FindEntityType(typeof(CustomerGeneric));
+        Assert.Equal(1000, entityType.FindProperty(nameof(CustomerGeneric.Name)).GetMaxLength());
+    }
+
     [ConditionalFact]
     public void EntityTypeConfigurationAttribute_should_throw_when_configuration_is_wrong_type()
     {
@@ -59,6 +70,12 @@ public void Configure(EntityTypeBuilder<Customer> builder)
             => builder.Property(c => c.Name).HasMaxLength(1000);
     }
 
+    private class CustomerGenericConfiguration : IEntityTypeConfiguration<CustomerGeneric>
+    {
+        public void Configure(EntityTypeBuilder<CustomerGeneric> builder)
+            => builder.Property(c => c.Name).HasMaxLength(1000);
+    }
+
     [EntityTypeConfiguration(typeof(CustomerConfiguration))]
     private class Customer
     {
@@ -67,6 +84,15 @@ private class Customer
         public string Name { get; set; }
     }
 
+
+    [EntityTypeConfigurationAttribute<CustomerGenericConfiguration, CustomerGeneric>]
+    private class CustomerGeneric
+    {
+        public int Id { get; set; }
+
+        public string Name { get; set; }
+    }
+
     [EntityTypeConfiguration(typeof(CustomerConfiguration))]
     private class InvalidCustomer
     {