Move DefaultErrorHandlingMode to request options and add AllowErrorHandlingModeOverride

src/HotChocolate/Core/src/Types/Execution/Options/IErrorHandlerOptionsAccessor.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using HotChocolate.Language;
 
 namespace HotChocolate.Execution.Options;
 
@@ -14,4 +15,15 @@ public interface IErrorHandlerOptionsAccessor
     /// <see cref="Debugger.IsAttached"/>.
     /// </summary>
     bool IncludeExceptionDetails { get; }
+
+    /// <summary>
+    /// Gets the default error handling mode for null propagation.
+    /// </summary>
+    ErrorHandlingMode DefaultErrorHandlingMode { get; }
+
+    /// <summary>
+    /// Gets a value indicating whether the <see cref="DefaultErrorHandlingMode"/> can be
+    /// overridden on a per-request basis.
+    /// </summary>
+    bool AllowErrorHandlingModeOverride { get; }
 }

src/HotChocolate/Core/src/Types/Execution/Options/RequestExecutorOptions.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using HotChocolate.Language;
 using HotChocolate.PersistedOperations;
 
 namespace HotChocolate.Execution.Options;
@@ -67,4 +68,17 @@ public PersistedOperationOptions PersistedOperations
             field = value;
         }
     } = new();
+
+    /// <summary>
+    /// Gets or sets the default error handling mode for null propagation.
+    /// <see cref="ErrorHandlingMode.Propagate"/> by default.
+    /// </summary>
+    public ErrorHandlingMode DefaultErrorHandlingMode { get; set; } = ErrorHandlingMode.Propagate;
+
+    /// <summary>
+    /// Gets or sets whether the <see cref="DefaultErrorHandlingMode"/> can be overridden
+    /// on a per-request basis.
+    /// <c>false</c> by default.
+    /// </summary>
+    public bool AllowErrorHandlingModeOverride { get; set; }
 }

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

@@ -2,6 +2,7 @@
 using System.Runtime.CompilerServices;
 using HotChocolate.Execution.DependencyInjection;
 using HotChocolate.Execution.Instrumentation;
+using HotChocolate.Execution.Options;
 using HotChocolate.Execution.Processing.Tasks;
 using HotChocolate.Fetching;
 using HotChocolate.Resolvers;
@@ -91,8 +92,12 @@ public void Initialize(
         _batchDispatcher = batchDispatcher;
         _variableIndex = variableIndex;
 
-        var errorHandlingMode = _requestContext.Request.ErrorHandlingMode
-            ?? _schema.GetOptions().DefaultErrorHandlingMode;
+        var executorOptions = _schema.Services.GetRequiredService<IRequestExecutorOptionsAccessor>();
+        var errorHandlingMode =
+            executorOptions.AllowErrorHandlingModeOverride
+                && _requestContext.Request.ErrorHandlingMode is { } requestedMode
+                    ? requestedMode
+                    : executorOptions.DefaultErrorHandlingMode;
         _propagateNullValues = errorHandlingMode is Language.ErrorHandlingMode.Propagate;
 
         IncludeFlags = operation.CreateIncludeFlags(variables);

src/HotChocolate/Core/src/Types/IReadOnlySchemaOptions.cs

@@ -1,7 +1,6 @@
 using System.Reflection;
 using HotChocolate.Configuration;
 using HotChocolate.Execution;
-using HotChocolate.Language;
 using HotChocolate.Types;
 
 namespace HotChocolate;
@@ -232,9 +231,4 @@ public interface IReadOnlySchemaOptions
     /// Applies the @serializeAs directive to scalar types that specify a serialization format.
     /// </summary>
     bool ApplySerializeAsToScalars { get; }
-
-    /// <summary>
-    /// Gets the default error handling mode for null propagation.
-    /// </summary>
-    ErrorHandlingMode DefaultErrorHandlingMode { get; }
 }

src/HotChocolate/Core/src/Types/SchemaOptions.cs

@@ -1,7 +1,6 @@
 using System.Reflection;
 using HotChocolate.Configuration;
 using HotChocolate.Execution;
-using HotChocolate.Language;
 using HotChocolate.Types;
 
 namespace HotChocolate;
@@ -190,9 +189,6 @@ public int OperationDocumentCacheSize
     /// <inheritdoc cref="IReadOnlySchemaOptions.ApplySerializeAsToScalars"/>
     public bool ApplySerializeAsToScalars { get; set; }
 
-    /// <inheritdoc cref="IReadOnlySchemaOptions.DefaultErrorHandlingMode"/>
-    public ErrorHandlingMode DefaultErrorHandlingMode { get; set; } = ErrorHandlingMode.Propagate;
-
     /// <summary>
     /// Creates a mutable options object from a read-only options object.
     /// </summary>
@@ -234,7 +230,6 @@ public static SchemaOptions FromOptions(IReadOnlySchemaOptions options)
             ApplyShareableToPageInfo = options.ApplyShareableToPageInfo,
             ApplyShareableToConnections = options.ApplyShareableToConnections,
             ApplyShareableToNodeFields = options.ApplyShareableToNodeFields,
-            ApplySerializeAsToScalars = options.ApplySerializeAsToScalars,
-            DefaultErrorHandlingMode = options.DefaultErrorHandlingMode
+            ApplySerializeAsToScalars = options.ApplySerializeAsToScalars
         };
 }

src/HotChocolate/Core/test/Execution.Tests/Errors/NullErrorPropagationTests.cs

@@ -250,15 +250,15 @@ public async Task List_NonNullElementHasError_NullMode(string fieldType)
     }
 
     [Fact]
-    public async Task DefaultErrorHandlingMode_AppliesFromSchemaOptions()
+    public async Task DefaultErrorHandlingMode_AppliesFromRequestExecutorOptions()
     {
         // arrange
         using var snapshot = SnapshotHelpers.StartResultSnapshot();
 
         var executor = await new ServiceCollection()
             .AddGraphQL()
             .AddDocumentFromString(SchemaText)
-            .ModifyOptions(o => o.DefaultErrorHandlingMode = ErrorHandlingMode.Null)
+            .ModifyRequestOptions(o => o.DefaultErrorHandlingMode = ErrorHandlingMode.Null)
             .AddResolver("Query", "foo", _ => new(new object()))
             .AddResolver("Foo", "nullable_list_nullable_element", _ => new(new[] { new object() }))
             .AddResolver("Foo", "nonnull_list_nullable_element", _ => new(new[] { new object() }))
@@ -285,12 +285,12 @@ public async Task DefaultErrorHandlingMode_AppliesFromSchemaOptions()
     }
 
     [Fact]
-    public async Task PerRequestOverride_OverridesSchemaDefault()
+    public async Task PerRequestOverride_OverridesDefaultErrorHandlingMode()
     {
         // arrange
         using var snapshot = SnapshotHelpers.StartResultSnapshot();
 
-        // Server configured with Propagate (default), but request specifies Null
+        // Request executor options use Propagate (default), but the request specifies Null.
         var executor = await CreateExecutorAsync();
 
         var request =
@@ -307,6 +307,43 @@ public async Task PerRequestOverride_OverridesSchemaDefault()
         snapshot.Add(result);
     }
 
+    [Fact]
+    public async Task PerRequestOverride_IsIgnored_When_AllowErrorHandlingModeOverride_IsDisabled()
+    {
+        // arrange
+        using var snapshot = SnapshotHelpers.StartResultSnapshot();
+
+        // Request executor options use Propagate (default) and override disabled (default).
+        // Even though the request asks for Null, the configured DefaultErrorHandlingMode must win.
+        var executor = await new ServiceCollection()
+            .AddGraphQL()
+            .AddDocumentFromString(SchemaText)
+            .AddResolver("Query", "foo", _ => new(new object()))
+            .AddResolver("Foo", "nullable_list_nullable_element", _ => new(new[] { new object() }))
+            .AddResolver("Foo", "nonnull_list_nullable_element", _ => new(new[] { new object() }))
+            .AddResolver("Foo", "nullable_list_nonnull_element", _ => new(new[] { new object() }))
+            .AddResolver("Foo", "nonnull_list_nonnull_element", _ => new(new[] { new object() }))
+            .AddResolver("Foo", "nonnull_prop", _ => new(new object()))
+            .AddResolver("Foo", "nullable_prop", _ => new(new object()))
+            .AddResolver("Bar", "a", c => new(c.GetGlobalStateOrDefault<string>("a")))
+            .AddResolver("Bar", "b", c => new(c.GetGlobalStateOrDefault<string>("b")))
+            .AddResolver("Bar", "c", _ => throw new GraphQLException("ERROR"))
+            .BuildRequestExecutorAsync();
+
+        var request =
+            OperationRequestBuilder.New()
+                .SetDocument("{ foo { nonnull_prop { b } } }")
+                .AddGlobalState("b", null)
+                .SetErrorHandlingMode(ErrorHandlingMode.Null)
+                .Build();
+
+        // act
+        var result = await executor.ExecuteAsync(request);
+
+        // assert
+        snapshot.Add(result);
+    }
+
     private const string SchemaText =
         """
         type Query {
@@ -334,6 +371,7 @@ private static async Task<IRequestExecutor> CreateExecutorAsync()
         return await new ServiceCollection()
             .AddGraphQL()
             .AddDocumentFromString(SchemaText)
+            .ModifyRequestOptions(o => o.AllowErrorHandlingModeOverride = true)
             .AddResolver("Query", "foo", _ => new(new object()))
             .AddResolver("Foo", "nullable_list_nullable_element", _ => new(new[] { new object() }))
             .AddResolver("Foo", "nonnull_list_nullable_element", _ => new(new[] { new object() }))

src/HotChocolate/Core/test/Execution.Tests/Errors/__snapshots__/NullErrorPropagationTests.PerRequestOverride_IsIgnored_When_AllowErrorHandlingModeOverride_IsDisabled.json

@@ -0,0 +1,18 @@
+{
+  "errors": [
+    {
+      "message": "Cannot return null for non-nullable field.",
+      "path": [
+        "foo",
+        "nonnull_prop",
+        "b"
+      ],
+      "extensions": {
+        "code": "HC0018"
+      }
+    }
+  ],
+  "data": {
+    "foo": null
+  }
+}

src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Extensions/FusionRequestContextExtensions.cs

@@ -115,7 +115,7 @@ internal static ErrorHandlingMode ErrorHandlingMode(
             return errorHandlingMode;
         }
 
-        return context.Schema.GetOptions().DefaultErrorHandlingMode;
+        return requestOptions.DefaultErrorHandlingMode;
     }
 
     internal static bool AllowErrorHandlingModeOverride(

src/HotChocolate/Fusion/src/Fusion.Execution/Execution/FusionOptions.cs

@@ -1,7 +1,6 @@
 using HotChocolate.Caching.Memory;
 using HotChocolate.Execution.Relay;
 using HotChocolate.Fusion.Types;
-using HotChocolate.Language;
 
 namespace HotChocolate.Fusion.Execution;
 
@@ -101,21 +100,6 @@ public int PathSegmentLocalPoolCapacity
         }
     } = 64;
 
-    /// <summary>
-    /// Gets or sets the default error handling mode.
-    /// <see cref="ErrorHandlingMode.Propagate"/> by default.
-    /// </summary>
-    public ErrorHandlingMode DefaultErrorHandlingMode
-    {
-        get;
-        set
-        {
-            ExpectMutableOptions();
-
-            field = value;
-        }
-    } = ErrorHandlingMode.Propagate;
-
     /// <summary>
     /// Gets or sets whether the request executor should be initialized lazily.
     /// <c>false</c> by default.
@@ -214,7 +198,6 @@ public FusionOptions Clone()
             OperationExecutionPlanCacheDiagnostics = OperationExecutionPlanCacheDiagnostics,
             OperationDocumentCacheSize = OperationDocumentCacheSize,
             PathSegmentLocalPoolCapacity = PathSegmentLocalPoolCapacity,
-            DefaultErrorHandlingMode = DefaultErrorHandlingMode,
             LazyInitialization = LazyInitialization,
             NodeIdSerializerFormat = NodeIdSerializerFormat,
             ApplySerializeAsToScalars = ApplySerializeAsToScalars,

src/HotChocolate/Fusion/src/Fusion.Execution/Execution/FusionRequestOptions.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using HotChocolate.Language;
 using HotChocolate.PersistedOperations;
 
 namespace HotChocolate.Fusion.Execution;
@@ -42,7 +43,22 @@ public bool CollectOperationPlanTelemetry
     }
 
     /// <summary>
-    /// Gets or sets whether the <see cref="FusionOptions.DefaultErrorHandlingMode"/> can be overriden
+    /// Gets or sets the default error handling mode.
+    /// <see cref="ErrorHandlingMode.Propagate"/> by default.
+    /// </summary>
+    public ErrorHandlingMode DefaultErrorHandlingMode
+    {
+        get;
+        set
+        {
+            ExpectMutableOptions();
+
+            field = value;
+        }
+    } = ErrorHandlingMode.Propagate;
+
+    /// <summary>
+    /// Gets or sets whether the <see cref="DefaultErrorHandlingMode"/> can be overridden
     /// on a per-request basis.
     /// <c>false</c> by default.
     /// </summary>
@@ -124,6 +140,7 @@ public FusionRequestOptions Clone()
         {
             ExecutionTimeout = ExecutionTimeout,
             CollectOperationPlanTelemetry = CollectOperationPlanTelemetry,
+            DefaultErrorHandlingMode = DefaultErrorHandlingMode,
             AllowErrorHandlingModeOverride = AllowErrorHandlingModeOverride,
             AllowOperationPlanRequests = AllowOperationPlanRequests,
             PersistedOperations = PersistedOperations,

src/HotChocolate/Fusion/test/Fusion.AspNetCore.Tests/SourceSchemaErrorTests.cs

@@ -61,7 +61,7 @@ public async Task OnError_SchemaDefault_Null_AppliesWithoutPerRequestOverride()
             ("A", server1)
         ],
         configureGatewayBuilder: builder =>
-            builder.ModifyOptions(o => o.DefaultErrorHandlingMode = ErrorHandlingMode.Null));
+            builder.ModifyRequestOptions(o => o.DefaultErrorHandlingMode = ErrorHandlingMode.Null));
 
         // act — no per-request onError override
         using var client = GraphQLHttpClient.Create(gateway.CreateClient());
@@ -83,6 +83,54 @@ public async Task OnError_SchemaDefault_Null_AppliesWithoutPerRequestOverride()
         await MatchSnapshotAsync(gateway, request, result);
     }
 
+    [Fact]
+    public async Task OnError_PerRequestOverride_IsIgnored_When_AllowErrorHandlingModeOverride_IsDisabled()
+    {
+        // arrange
+        using var server1 = CreateSourceSchema(
+            "A",
+            b => b.AddQueryType<SourceSchema1.Query>());
+
+        using var server2 = CreateSourceSchema(
+            "B",
+            b => b.AddQueryType<SourceSchema3.Query>());
+
+        using var gateway = await CreateCompositeSchemaAsync(
+        [
+            ("A", server1),
+            ("B", server2)
+        ],
+        configureGatewayBuilder: builder =>
+            builder.ModifyRequestOptions(o =>
+            {
+                o.DefaultErrorHandlingMode = ErrorHandlingMode.Propagate;
+                o.AllowErrorHandlingModeOverride = false;
+            }));
+
+        // act
+        // Even though the request asks for Null, the gateway must ignore the override
+        // and apply the configured Propagate mode (so data is fully omitted).
+        using var client = GraphQLHttpClient.Create(gateway.CreateClient());
+
+        var request = new OperationRequest(
+            """
+            {
+              topProduct {
+                price
+                name
+              }
+            }
+            """,
+            onError: ErrorHandlingMode.Null);
+
+        using var result = await client.PostAsync(
+            request,
+            new Uri("http://localhost:5000/graphql"));
+
+        // assert
+        await MatchSnapshotAsync(gateway, request, result);
+    }
+
     [Fact]
     public async Task OnError_Null_OnSourceSchema_Forwards_To_Subgraph_Request()
     {