Fixed Pool Reset Issue

Author: michaelstaib

src/HotChocolate/Directory.Build.props

@@ -4,6 +4,6 @@
     <PackageIcon>hotchocolate-signet.png</PackageIcon>
   </PropertyGroup>
   <PropertyGroup>
-    <NitroVersion>28.0.14</NitroVersion>
+    <NitroVersion>29.0.0-insider.22</NitroVersion>
   </PropertyGroup>
 </Project>

src/HotChocolate/Fusion-vnext/src/Fusion.Execution/Execution/Results/ResultDataBatch.cs

@@ -10,6 +10,9 @@ namespace HotChocolate.Fusion.Execution;
     private readonly int _maxAllowedCapacity;
     private readonly T[] _items;
     private int _next = -1;
+#pragma warning disable IDE0052 // Remove unread private members
+    private readonly int _inst;
+#pragma warning restore IDE0052 // Remove unread private members
 
     public ResultDataBatch(int batchSize, int defaultCapacity = 8, int maxAllowedCapacity = 16)
     {
@@ -26,6 +29,8 @@ public ResultDataBatch(int batchSize, int defaultCapacity = 8, int maxAllowedCap
         {
             _items[i] = CreateItem();
         }
+
+        _inst = Interlocked.Increment(ref InstanceCounter.Counter);
     }
 
     private T CreateItem()
@@ -62,7 +67,7 @@ public void Reset()
             return;
         }
 
-        var usedItem = _next < _items.Length ? _next : _items.Length;
+        var usedItem = _next < _items.Length ? _next + 1 : _items.Length;
         ref var item = ref MemoryMarshal.GetReference(_items.AsSpan());
         ref var end = ref Unsafe.Add(ref item, usedItem);
 
@@ -78,3 +83,8 @@ public void Reset()
         _next = -1;
     }
 }
+
+public static class InstanceCounter
+{
+    public static int Counter;
+}

src/HotChocolate/Fusion-vnext/test/Fusion.AspNetCore.Tests/BookStoreTests.cs

@@ -44,6 +44,62 @@ public async Task Fetch_Book_From_SourceSchema1()
         response.MatchSnapshot();
     }
 
+    [Fact]
+    public async Task Fetch_Book_From_SourceSchema1_Two_Requests()
+    {
+        // arrange
+        using var server1 = CreateSourceSchema(
+            "A",
+            b => b.AddQueryType<SourceSchema1.Query>());
+
+        using var server2 = CreateSourceSchema(
+            "B",
+            b => b.AddQueryType<SourceSchema2.Query>());
+
+        // act
+        using var gateway = await CreateCompositeSchemaAsync(
+        [
+            ("A", server1),
+            ("B", server2),
+        ]);
+
+        // assert
+        using var client = GraphQLHttpClient.Create(gateway.CreateClient());
+
+        using var result1 = await client.PostAsync(
+            """
+            {
+              bookById(id: 1) {
+                id
+                title
+              }
+            }
+            """,
+            new Uri("http://localhost:5000/graphql"));
+
+        using (var response = await result1.ReadAsResultAsync())
+        {
+            response.MatchSnapshot();
+        }
+
+        using var result2 = await client.PostAsync(
+                """
+            {
+              bookById(id: 1) {
+                id
+                title
+              }
+            }
+            """,
+                new Uri("http://localhost:5000/graphql"));
+
+        // act
+        using (var response = await result2.ReadAsResultAsync())
+        {
+            response.MatchSnapshot();
+        }
+    }
+
     [Fact]
     public async Task Fetch_Book_From_SourceSchema1_And_Author_From_SourceSchema2()
     {

src/HotChocolate/Fusion-vnext/test/Fusion.AspNetCore.Tests/__snapshots__/BookStoreTests.Fetch_Book_From_SourceSchema1_Two_Requests.snap

@@ -0,0 +1,8 @@
+{
+  "data": {
+    "bookById": {
+      "id": 1,
+      "title": "C# in Depth"
+    }
+  }
+}