Fixed state issues when streaming.

src/HotChocolate/Core/src/Execution/Pipeline/OperationExecutionMiddleware.cs

@@ -1,10 +1,10 @@
 using System;
 using System.Threading.Tasks;
+using HotChocolate.Execution.DependencyInjection;
 using HotChocolate.Execution.Processing;
 using HotChocolate.Fetching;
 using HotChocolate.Language;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.ObjectPool;
 using static HotChocolate.Execution.GraphQLRequestFlags;
 using static HotChocolate.Execution.ThrowHelper;
 
@@ -13,7 +13,7 @@ namespace HotChocolate.Execution.Pipeline;
 internal sealed class OperationExecutionMiddleware
 {
     private readonly RequestDelegate _next;
-    private readonly ObjectPool<OperationContext> _operationContextPool;
+    private readonly IFactory<OperationContextOwner> _contextFactory;
     private readonly QueryExecutor _queryExecutor;
     private readonly SubscriptionExecutor _subscriptionExecutor;
     private readonly ITransactionScopeHandler _transactionScopeHandler;
@@ -22,15 +22,15 @@ internal sealed class OperationExecutionMiddleware
 
     public OperationExecutionMiddleware(
         RequestDelegate next,
-        ObjectPool<OperationContext> operationContextPool,
+        IFactory<OperationContextOwner> contextFactory,
         QueryExecutor queryExecutor,
         SubscriptionExecutor subscriptionExecutor,
         [SchemaService] ITransactionScopeHandler transactionScopeHandler)
     {
         _next = next ??
             throw new ArgumentNullException(nameof(next));
-        _operationContextPool = operationContextPool ??
-            throw new ArgumentNullException(nameof(operationContextPool));
+        _contextFactory = contextFactory ??
+            throw new ArgumentNullException(nameof(contextFactory));
         _queryExecutor = queryExecutor ??
             throw new ArgumentNullException(nameof(queryExecutor));
         _subscriptionExecutor = subscriptionExecutor ??
@@ -76,7 +76,7 @@ private async Task ExecuteOperationAsync(
     {
         if (operation.Definition.Operation == OperationType.Subscription)
         {
-            // since the context is pooled we need to clone the context for
+            // since the request context is pooled we need to clone the context for
             // long running executions.
             var cloned = context.Clone();
 
@@ -91,7 +91,8 @@ private async Task ExecuteOperationAsync(
         }
         else
         {
-            var operationContext = _operationContextPool.Get();
+            var operationContextOwner = _contextFactory.Create();
+            var operationContext = operationContextOwner.OperationContext;
 
             try
             {
@@ -102,22 +103,21 @@ await ExecuteQueryOrMutationAsync(
                 if (operationContext.DeferredScheduler.HasResults &&
                     context.Result is IQueryResult result)
                 {
-                    var stream = operationContext.DeferredScheduler.CreateResultStream(result);
-
-                    context.Result = new ResponseStream(
-                        () => stream,
+                    var results = operationContext.DeferredScheduler.CreateResultStream(result);
+                    var responseStream = new ResponseStream(
+                        () => results,
                         ExecutionResultKind.DeferredResult);
-                    context.Result.RegisterForCleanup(result);
+                    responseStream.RegisterForCleanup(result);
+                    responseStream.RegisterForCleanup(operationContextOwner);
+                    context.Result = responseStream;
+                    operationContextOwner = null;
                 }
 
                 await _next(context).ConfigureAwait(false);
             }
             finally
             {
-                if (operationContext is not null)
-                {
-                    _operationContextPool.Return(operationContext);
-                }
+                operationContextOwner?.Dispose();
             }
         }
     }

src/HotChocolate/Core/src/Execution/Processing/DeferredStream.cs

@@ -76,30 +76,26 @@ protected override async Task ExecuteAsync(
         uint patchId)
     {
         var operationContext = operationContextOwner.OperationContext;
-        var aborted = operationContext.RequestAborted;
-        var error = false;
 
         try
         {
             _task ??= new StreamExecutionTask(this);
             _task.Reset(operationContext, resultId);
-
             operationContext.Scheduler.Register(_task);
             await operationContext.Scheduler.ExecuteAsync().ConfigureAwait(false);
 
             // if there is no child task, then there is no more data, so we can complete.
             if (_task.ChildTask is null)
             {
                 operationContext.DeferredScheduler.Complete(new(resultId, parentResultId));
-                operationContextOwner.Dispose();
                 return;
             }
 
             var item = _task.ChildTask.ParentResult[0].Value!;
 
             var result = operationContext
                 .SetLabel(Label)
-                .SetPath(operationContext.PathFactory.Append(Path, Index))
+                .SetPath(operationContext.PathFactory.Append(Path, Index).Clone())
                 .SetItems(new[] { item })
                 .SetPatchId(patchId)
                 .BuildResult();
@@ -110,19 +106,15 @@ protected override async Task ExecuteAsync(
             operationContext.DeferredScheduler.Register(this, patchId);
             operationContext.DeferredScheduler.Complete(new(resultId, parentResultId, result));
         }
-        catch(Exception ex)
+        catch (Exception ex)
         {
             var builder = operationContext.ErrorHandler.CreateUnexpectedError(ex);
             var result = QueryResultBuilder.CreateError(builder.Build());
             operationContext.DeferredScheduler.Complete(new(resultId, parentResultId, result));
-            error = true;
         }
         finally
         {
-            if (error || aborted.IsCancellationRequested)
-            {
-                operationContextOwner.Dispose();
-            }
+            operationContextOwner.Dispose();
         }
     }
 

src/HotChocolate/Core/src/Execution/Processing/DeferredWorkStateOwner.cs

@@ -19,7 +19,7 @@ public DeferredWorkStateOwner(DeferredWorkState state, ObjectPool<DeferredWorkSt
 
     public void Dispose()
     {
-        if (_disposed == 0 && Interlocked.CompareExchange(ref _disposed, 0, 1) == 0)
+        if (_disposed == 0 && Interlocked.CompareExchange(ref _disposed, 1, 0) == 0)
         {
             _statePool.Return(State);
         }

src/HotChocolate/Core/src/Execution/Processing/OperationContext.Pooling.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Threading;
 using HotChocolate.Execution.DependencyInjection;

src/HotChocolate/Core/test/Execution.Tests/StreamTests.cs

@@ -79,7 +79,6 @@ persons @stream(initialCount: 1) {
         Assert.IsType<ResponseStream>(result).MatchSnapshot();
     }
 
-
     [Fact]
     public async Task Stream_Label_Set_To_abc()
     {