Merge pull request #72 from EFNext/fix/include-then-async

added IAsyncEnumerable support to IncludableExpressiveQueryableWrapper

Author: koenbeuk

src/ExpressiveSharp.EntityFrameworkCore/ExpressiveDbSet.cs

@@ -17,7 +17,9 @@ public class ExpressiveDbSet<TEntity> : DbSet<TEntity>, IExpressiveQueryable<TEn
     private readonly DbSet<TEntity> _inner;
     private readonly IQueryable<TEntity> _queryable;
 
-    public ExpressiveDbSet(DbSet<TEntity> inner)
+    // Constructed only via AsExpressiveDbSet() (through InternalExpressiveDbSet) so every
+    // instance is the async-capable runtime subclass. See InternalExpressiveDbSet.
+    private protected ExpressiveDbSet(DbSet<TEntity> inner)
     {
         _inner = inner;
         _queryable = inner;

src/ExpressiveSharp.EntityFrameworkCore/Extensions/DbSetExtensions.cs

@@ -1,4 +1,5 @@
 using ExpressiveSharp.EntityFrameworkCore;
+using ExpressiveSharp.EntityFrameworkCore.Infrastructure.Internal;
 
 // ReSharper disable once CheckNamespace — intentionally in Microsoft.EntityFrameworkCore for discoverability
 namespace Microsoft.EntityFrameworkCore;
@@ -7,5 +8,5 @@ public static class DbSetExtensions
 {
     public static ExpressiveDbSet<TEntity> AsExpressiveDbSet<TEntity>(this DbSet<TEntity> dbSet)
         where TEntity : class
-        => new(dbSet);
+        => new InternalExpressiveDbSet<TEntity>(dbSet);
 }

src/ExpressiveSharp.EntityFrameworkCore/Infrastructure/IncludableExpressiveQueryableWrapper.cs

@@ -5,7 +5,7 @@
 namespace ExpressiveSharp.EntityFrameworkCore.Infrastructure;
 
 internal sealed class IncludableExpressiveQueryableWrapper<TEntity, TProperty>
-    : IIncludableExpressiveQueryable<TEntity, TProperty>
+    : IIncludableExpressiveQueryable<TEntity, TProperty>, IAsyncEnumerable<TEntity>
     where TEntity : class
 {
     private readonly IIncludableQueryable<TEntity, TProperty> _inner;
@@ -19,4 +19,14 @@ public IncludableExpressiveQueryableWrapper(IIncludableQueryable<TEntity, TPrope
 
     IEnumerator<TEntity> IEnumerable<TEntity>.GetEnumerator() => _inner.GetEnumerator();
     IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)_inner).GetEnumerator();
+
+    IAsyncEnumerator<TEntity> IAsyncEnumerable<TEntity>.GetAsyncEnumerator(CancellationToken cancellationToken)
+    {
+        if (_inner is IAsyncEnumerable<TEntity> asyncEnumerable)
+            return asyncEnumerable.GetAsyncEnumerator(cancellationToken);
+
+        throw new InvalidOperationException(
+            $"The source IQueryable<{typeof(TEntity).Name}> does not implement IAsyncEnumerable<{typeof(TEntity).Name}>. " +
+            "Async operations require an async-capable provider such as Entity Framework Core.");
+    }
 }

src/ExpressiveSharp.EntityFrameworkCore/Infrastructure/Internal/InternalExpressiveDbSet.cs

@@ -0,0 +1,25 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace ExpressiveSharp.EntityFrameworkCore.Infrastructure.Internal;
+
+/// <summary>
+/// The concrete runtime instance produced by <c>AsExpressiveDbSet()</c>. It implements
+/// <see cref="IAsyncEnumerable{T}"/> — satisfied by the inherited
+/// <see cref="ExpressiveDbSet{TEntity}.GetAsyncEnumerator"/> — so EF Core's streaming async
+/// terminals (<c>ToListAsync</c>/<c>ToArrayAsync</c>/...), which runtime-cast the source to
+/// <see cref="IAsyncEnumerable{T}"/>, work directly on the set.
+/// <para>
+/// The interface lives here rather than on the public <see cref="ExpressiveDbSet{TEntity}"/> so
+/// callers never hold a static type that is both <see cref="IQueryable{T}"/> and
+/// <see cref="IAsyncEnumerable{T}"/> — which on .NET 10 makes those terminals ambiguous between
+/// <c>System.Linq.AsyncEnumerable</c> and EF Core's extensions. This mirrors EF Core's own
+/// public <c>DbSet&lt;T&gt;</c> / internal <c>InternalDbSet&lt;T&gt;</c> split.
+/// </para>
+/// </summary>
+internal sealed class InternalExpressiveDbSet<TEntity> : ExpressiveDbSet<TEntity>, IAsyncEnumerable<TEntity>
+    where TEntity : class
+{
+    public InternalExpressiveDbSet(DbSet<TEntity> inner) : base(inner)
+    {
+    }
+}

tests/ExpressiveSharp.EntityFrameworkCore.IntegrationTests/Infrastructure/AsyncQueryableTestBase.cs

@@ -7,7 +7,11 @@ namespace ExpressiveSharp.EntityFrameworkCore.IntegrationTests.Infrastructure;
 public abstract class AsyncQueryableTestBase : EFCoreRelationalTestBase
 {
     [TestInitialize]
-    public Task SeedStoreData() => Context.SeedStoreAsync();
+    public async Task SeedStoreData()
+    {
+        await Context.SeedStoreAsync();
+        Context.ChangeTracker.Clear();
+    }
 
     [TestMethod]
     public async Task AnyAsync_WithPredicate_Executes()
@@ -117,6 +121,61 @@ public async Task Include_Where_ToListAsync_LoadsNavigation()
         Assert.IsTrue(results.All(o => o.Customer != null));
     }
 
+    [TestMethod]
+    public async Task ExpressiveDbSet_ToListAsync_DirectTerminal_Executes()
+    {
+        // Streaming terminal directly on the ExpressiveDbSet (no intervening operator to
+        // re-wrap it). ToListAsync casts the source to IAsyncEnumerable<T>.
+        var results = await Context.ExpressiveOrders.ToListAsync();
+
+        Assert.AreEqual(4, results.Count);
+    }
+
+    [TestMethod]
+    public async Task ExpressiveDbSet_ToArrayAsync_DirectTerminal_Executes()
+    {
+        var results = await Context.ExpressiveOrders.ToArrayAsync();
+
+        Assert.AreEqual(4, results.Length);
+    }
+
+    [TestMethod]
+    public async Task Include_ToListAsync_DirectTerminal_LoadsNavigation()
+    {
+        var results = await Context.ExpressiveOrders
+            .Include(o => o.Customer)
+            .ToListAsync();
+
+        Assert.AreEqual(4, results.Count);
+        Assert.AreEqual(3, results.Count(o => o.Customer != null));
+    }
+
+    [TestMethod]
+    public async Task Include_ToArrayAsync_DirectTerminal_LoadsNavigation()
+    {
+        var results = await Context.ExpressiveOrders
+            .Include(o => o.Customer)
+            .ToArrayAsync();
+
+        Assert.AreEqual(4, results.Length);
+        Assert.AreEqual(3, results.Count(o => o.Customer != null));
+    }
+
+    [TestMethod]
+    public async Task Include_ThenInclude_ToListAsync_DirectTerminal_LoadsTwoLevelNavigation()
+    {
+        var results = await Context.ExpressiveOrders
+            .Include(o => o.Customer)
+            .ThenInclude(c => c!.Address)
+            .ToListAsync();
+
+        Assert.AreEqual(4, results.Count);
+        var aliceOrder = results.Single(o => o.CustomerId == 1);
+        Assert.IsNotNull(aliceOrder.Customer);
+        Assert.IsNotNull(aliceOrder.Customer!.Address);
+        Assert.AreEqual("New York", aliceOrder.Customer.Address!.City);
+    }
+
     [TestMethod]
     public async Task TagWith_Where_FirstAsync_ExecutesCorrectly()
     {

tests/ExpressiveSharp.EntityFrameworkCore.IntegrationTests/Infrastructure/IncludeTestBase.cs

@@ -7,7 +7,11 @@ namespace ExpressiveSharp.EntityFrameworkCore.IntegrationTests.Infrastructure;
 public abstract class IncludeTestBase : EFCoreRelationalTestBase
 {
     [TestInitialize]
-    public Task SeedStoreData() => Context.SeedStoreAsync();
+    public async Task SeedStoreData()
+    {
+        await Context.SeedStoreAsync();
+        Context.ChangeTracker.Clear();
+    }
 
     [TestMethod]
     public async Task Include_LoadsRelatedCustomer()