Never map projectable properties

EntityFrameworkCore.Projectables.sln

@@ -18,6 +18,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 	ProjectSection(SolutionItems) = preProject
 		.editorconfig = .editorconfig
 		Directory.Build.props = Directory.Build.props
+		Directory.Packages.props = Directory.Packages.props
 	EndProjectSection
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "EntityFrameworkCore.Projectables", "src\EntityFrameworkCore.Projectables\EntityFrameworkCore.Projectables.csproj", "{EE4D6CC1-78DE-4279-A567-C3D360C479F8}"

global.json

@@ -0,0 +1,5 @@
+{
+  "sdk": {
+    "version": "8.0.400"
+  }
+}

src/EntityFrameworkCore.Projectables/Infrastructure/Internal/ProjectablePropertiesNotMappedConvention.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using Microsoft.EntityFrameworkCore.Metadata.Conventions;
+
+namespace EntityFrameworkCore.Projectables.Infrastructure.Internal;
+
+public class ProjectablePropertiesNotMappedConvention : IEntityTypeAddedConvention
+{
+    public void ProcessEntityTypeAdded(IConventionEntityTypeBuilder entityTypeBuilder, IConventionContext<IConventionEntityTypeBuilder> context)
+    {
+        if (entityTypeBuilder.Metadata.ClrType is null)
+        {
+            return;
+        }
+
+        foreach (var property in entityTypeBuilder.Metadata.ClrType.GetRuntimeProperties())
+        {
+            if (property.GetCustomAttribute<ProjectableAttribute>() is not null)
+            {
+                entityTypeBuilder.Ignore(property.Name);
+            }
+        }
+    }
+}

src/EntityFrameworkCore.Projectables/Infrastructure/Internal/ProjectablePropertiesNotMappedConventionPlugin.cs

@@ -0,0 +1,13 @@
+using Microsoft.EntityFrameworkCore.Metadata.Conventions;
+using Microsoft.EntityFrameworkCore.Metadata.Conventions.Infrastructure;
+
+namespace EntityFrameworkCore.Projectables.Infrastructure.Internal;
+
+public class ProjectablePropertiesNotMappedConventionPlugin : IConventionSetPlugin
+{
+    public ConventionSet ModifyConventions(ConventionSet conventionSet)
+    {
+        conventionSet.EntityTypeAddedConventions.Add(new ProjectablePropertiesNotMappedConvention());
+        return conventionSet;
+    }
+}

src/EntityFrameworkCore.Projectables/Infrastructure/Internal/ProjectionOptionsExtension.cs

@@ -1,6 +1,8 @@
 using EntityFrameworkCore.Projectables.Infrastructure;
 using EntityFrameworkCore.Projectables.Infrastructure.Internal;
 using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata.Conventions;
+using Microsoft.EntityFrameworkCore.Metadata.Conventions.Infrastructure;
 using Microsoft.EntityFrameworkCore.Query;
 using Microsoft.EntityFrameworkCore.Query.Internal;
 using Microsoft.Extensions.DependencyInjection;
@@ -36,6 +38,9 @@ public ProjectionOptionsExtension(ProjectionOptionsExtension copyFrom)
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "EF1001:Internal EF Core API usage.", Justification = "Needed")]
         public void ApplyServices(IServiceCollection services)
         {
+            // Register a convention that will ignore properties marked with the ProjectableAttribute
+            services.AddScoped<IConventionSetPlugin, ProjectablePropertiesNotMappedConventionPlugin>();
+
             static object CreateTargetInstance(IServiceProvider services, ServiceDescriptor descriptor)
             {
                 if (descriptor.ImplementationInstance is not null)

tests/EntityFrameworkCore.Projectables.FunctionalTests/EnumerableProjectableTests.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using EntityFrameworkCore.Projectables.FunctionalTests.Helpers;
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests
+{
+    public class EnumerableProjectableTests
+    {
+        public class Product
+        {
+            public int Id { get; set; }
+
+            public List<ProductPrice> Prices { get; } = [];
+
+            [Projectable]
+            public IEnumerable<ProductPrice> CheapPrices => Prices.Where(x => x.Price < 10D);
+        }
+
+        public class ProductPrice
+        {
+            public int Id { get; set; }
+
+            public double Price { get; set; }
+        }
+
+        [Fact]
+        public void ProjectableProperty_IsIgnoredFromMapping()
+        {
+            var dbContext = new SampleDbContext<Product>();
+            var productPriceType = dbContext.Model.GetEntityTypes().Single(x => x.ClrType == typeof(ProductPrice));
+
+            // Assert 3 properties: Id, Price, ProductId (synthetic)
+            Assert.Equal(3, productPriceType.GetProperties().Count());  
+        }
+    }
+}