Associate subgraph transport errors with fields (#7347)

src/HotChocolate/AspNetCore/src/Transport.Http/GraphQLHttpResponse.cs

@@ -134,8 +134,9 @@ public ValueTask<OperationResult> ReadAsResultAsync(CancellationToken cancellati
 #endif
         }
 
-        // if the media type is anything else we will return a transport error.
-        return new ValueTask<OperationResult>(_transportError);
+        _message.EnsureSuccessStatusCode();
+
+        throw new InvalidOperationException("Received a successful response with an unexpected content type.");
     }
 
 #if NET6_0_OR_GREATER

src/HotChocolate/AspNetCore/test/Transport.Http.Tests/GraphQLHttpClientTests.cs

@@ -1,3 +1,4 @@
+using System.Net;
 using System.Text.Json;
 using CookieCrumble;
 using HotChocolate.AspNetCore.Tests.Utilities;
@@ -14,6 +15,82 @@ public class GraphQLHttpClientTests : ServerTestBase
     /// <inheritdoc />
     public GraphQLHttpClientTests(TestServerFactory serverFactory) : base(serverFactory) { }
 
+    [Fact]
+    public async Task Post_Http_200_Wrong_Content_Type()
+    {
+        // arrange
+        var httpClient = new HttpClient(new CustomHttpClientHandler(HttpStatusCode.OK));
+
+        var query =
+            """
+            query {
+              hero(episode: JEDI) {
+                name
+              }
+            }
+            """;
+
+        var client = new DefaultGraphQLHttpClient(httpClient);
+
+        // act
+        var response = await client.PostAsync(query, "/graphql");
+
+        async Task Error() => await response.ReadAsResultAsync();
+
+        // assert
+        var exception = await Assert.ThrowsAsync<InvalidOperationException>(Error);
+        Assert.Equal("Received a successful response with an unexpected content type.", exception.Message);
+    }
+
+    [Fact]
+    public async Task Post_Http_404_Wrong_Content_Type()
+    {
+        var httpClient = new HttpClient(new CustomHttpClientHandler(HttpStatusCode.NotFound));
+
+        var query =
+            """
+            query {
+              hero(episode: JEDI) {
+                name
+              }
+            }
+            """;
+
+        var client = new DefaultGraphQLHttpClient(httpClient);
+
+        // act
+        var response = await client.PostAsync(query, "/graphql");
+
+        async Task Error() => await response.ReadAsResultAsync();
+
+        // assert
+        await Assert.ThrowsAsync<HttpRequestException>(Error);
+    }
+
+    [Fact]
+    public async Task Post_Transport_Error()
+    {
+        var httpClient = new HttpClient(new CustomHttpClientHandler());
+
+        var query =
+            """
+            query {
+              hero(episode: JEDI) {
+                name
+              }
+            }
+            """;
+
+        var client = new DefaultGraphQLHttpClient(httpClient);
+
+        // act
+        async Task Error() => await client.PostAsync(query, "/graphql");
+
+        // assert
+        var exception = await Assert.ThrowsAsync<Exception>(Error);
+        Assert.Equal("Something went wrong", exception.Message);
+    }
+
     [Fact]
     public async Task Post_GraphQL_Query_With_RequestUri()
     {
@@ -778,6 +855,21 @@ public async Task Post_GraphQL_FileUpload_With_ObjectValueNode()
             """);
     }
 
+    private class CustomHttpClientHandler(HttpStatusCode? httpStatusCode = null) : HttpClientHandler
+    {
+        protected override Task<HttpResponseMessage> SendAsync(
+            HttpRequestMessage request,
+            CancellationToken cancellationToken)
+        {
+            if (httpStatusCode.HasValue)
+            {
+                return Task.FromResult(new HttpResponseMessage(httpStatusCode.Value));
+            }
+
+            throw new Exception("Something went wrong");
+        }
+    }
+
     public class ErrorSubscription
     {
         public async IAsyncEnumerable<string> CreateStream()

src/HotChocolate/Fusion/src/Core/Clients/DefaultHttpGraphQLClient.cs

@@ -7,7 +7,6 @@ namespace HotChocolate.Fusion.Clients;
 
 internal sealed class DefaultHttpGraphQLClient : IGraphQLClient
 {
-    private static readonly GraphQLResponse _transportError = new(CreateTransportError());
     private readonly HttpClientConfiguration _config;
     private readonly DefaultGraphQLHttpClient _client;
 
@@ -51,20 +50,12 @@ private async Task<GraphQLResponse> ExecuteInternalAsync(SubgraphGraphQLRequest
             var result = await response.ReadAsResultAsync(ct).ConfigureAwait(false);
             return new GraphQLResponse(result);
         }
-        catch
+        catch (Exception exception)
         {
-            return _transportError;
+            return new GraphQLResponse(exception);
         }
     }
 
-    private static JsonElement CreateTransportError()
-    {
-        return JsonDocument.Parse(
-            """
-            [{"message": "Internal Execution Error"}]
-            """).RootElement;
-    }
-
     public ValueTask DisposeAsync()
     {
         _client.Dispose();

src/HotChocolate/Fusion/src/Core/Clients/GraphQLResponse.cs

@@ -7,9 +7,9 @@ public sealed class GraphQLResponse : IDisposable
 {
     private readonly IDisposable? _resource;
 
-    internal GraphQLResponse(JsonElement errors)
+    internal GraphQLResponse(Exception transportException)
     {
-        Errors = errors;
+        TransportException = transportException;
     }
 
     internal GraphQLResponse(OperationResult result)
@@ -20,32 +20,16 @@ internal GraphQLResponse(OperationResult result)
         Extensions = result.Extensions;
     }
 
-    public GraphQLResponse(JsonDocument document)
-    {
-        _resource = document;
-
-        if (document.RootElement.TryGetProperty(ResponseProperties.Data, out var value))
-        {
-            Data = value;
-        }
-
-        if (document.RootElement.TryGetProperty(ResponseProperties.Errors, out value))
-        {
-            Errors = value;
-        }
-
-        if (document.RootElement.TryGetProperty(ResponseProperties.Extensions, out value))
-        {
-            Extensions = value;
-        }
-    }
-
     public JsonElement Data { get; }
 
     public JsonElement Errors { get; }
 
     public JsonElement Extensions { get; }
 
+    public Exception? TransportException { get; private set; }
+
     public void Dispose()
-        => _resource?.Dispose();
+    {
+        _resource?.Dispose();
+    }
 }

src/HotChocolate/Fusion/src/Core/Execution/ExecutionUtils.cs

@@ -5,6 +5,7 @@
 using HotChocolate.Execution.Processing;
 using HotChocolate.Fusion.Execution.Nodes;
 using HotChocolate.Fusion.Metadata;
+using HotChocolate.Fusion.Planning;
 using HotChocolate.Fusion.Utilities;
 using HotChocolate.Language;
 using HotChocolate.Language.Visitors;
@@ -394,8 +395,8 @@ private static void ExtractSelectionResults(
 
             while (Unsafe.IsAddressLessThan(ref selection, ref endSelection))
             {
-                if (data.ValueKind is not JsonValueKind.Null &&
-                    data.TryGetProperty(selection.ResponseName, out var value))
+                if (data.ValueKind is not JsonValueKind.Null
+                    && data.TryGetProperty(selection.ResponseName, out var value))
                 {
                     selectionData = selectionData.AddResult(new JsonResult(schemaName, value));
                 }
@@ -417,8 +418,8 @@ private static void ExtractSelectionResults(
 
                 while (Unsafe.IsAddressLessThan(ref selection, ref endSelection))
                 {
-                    if (element.ValueKind is not JsonValueKind.Null &&
-                        element.TryGetProperty(selection.ResponseName, out var value))
+                    if (element.ValueKind is not JsonValueKind.Null
+                        && element.TryGetProperty(selection.ResponseName, out var value))
                     {
                         selectionData = selectionData.AddResult(new JsonResult(schemaName, value));
                     }
@@ -494,6 +495,33 @@ public static void TryInitializeExecutionState(QueryPlan queryPlan, ExecutionSta
         executionState.IsInitialized = true;
     }
 
+    public static void CreateTransportErrors(
+        Exception transportException,
+        ResultBuilder resultBuilder,
+        IErrorHandler errorHandler,
+        ObjectResult selectionSetResult,
+        List<RootSelection> rootSelections,
+        string subgraphName,
+        bool addDebugInfo)
+    {
+        foreach (var rootSelection in rootSelections)
+        {
+            var errorBuilder = errorHandler.CreateUnexpectedError(transportException);
+
+            errorBuilder.AddLocation(rootSelection.Selection.SyntaxNode);
+            errorBuilder.SetPath(PathHelper.CreatePathFromContext(rootSelection.Selection, selectionSetResult, 0));
+
+            if (addDebugInfo)
+            {
+                errorBuilder.SetExtension("subgraphName", subgraphName);
+            }
+
+            var error = errorHandler.Handle(errorBuilder.Build());
+
+            resultBuilder.AddError(error);
+        }
+    }
+
     public static void ExtractErrors(
         DocumentNode document,
         OperationDefinitionNode operation,
@@ -509,10 +537,11 @@ public static void ExtractErrors(
             return;
         }
 
-        var path = PathHelper.CreatePathFromContext(selectionSetResult);
+        var parentPath = PathHelper.CreatePathFromContext(selectionSetResult);
+
         foreach (var error in errors.EnumerateArray())
         {
-            ExtractError(document, operation, resultBuilder, errorHandler, error, path, pathDepth, addDebugInfo);
+            ExtractError(document, operation, resultBuilder, errorHandler, error, parentPath, pathDepth, addDebugInfo);
         }
     }
 
@@ -724,7 +753,7 @@ private sealed class ErrorPathVisitor : SyntaxWalker<ErrorPathContext>
 
             Visit(operation, context);
 
-            var field =  context.Field;
+            var field = context.Field;
 
             context.Reset();
             Interlocked.Exchange(ref _errorPathContext, context);

src/HotChocolate/Fusion/src/Core/Execution/Nodes/Resolve.cs

@@ -148,6 +148,18 @@ private void ProcessResponses(
             var exportKeys = state.Requires;
             var variableValues = state.VariableValues;
 
+            if (response.TransportException is not null)
+            {
+                CreateTransportErrors(
+                    response.TransportException,
+                    context.Result,
+                    context.ErrorHandler,
+                    selectionSetResult,
+                    RootSelections,
+                    subgraphName,
+                    context.ShowDebugInfo);
+            }
+
             ExtractErrors(
                 context.Operation.Document,
                 context.Operation.Definition,

src/HotChocolate/Fusion/src/Core/Execution/Nodes/ResolveByKeyBatch.cs

@@ -90,7 +90,7 @@ protected override async Task OnExecuteAsync(
             // query plan nodes be interested in it.
             lock (executionState)
             {
-                ProcessResult(context, response, batchExecutionState);
+                ProcessResult(context, response, batchExecutionState, SubgraphName);
             }
         }
         catch (Exception ex)
@@ -142,14 +142,30 @@ private static void InitializeRequests(FusionExecutionContext context, List<Exec
     private void ProcessResult(
         FusionExecutionContext context,
         GraphQLResponse response,
-        BatchExecutionState[] batchExecutionState)
+        BatchExecutionState[] batchExecutionState,
+        string subgraphName)
     {
         var result = UnwrapResult(response, Requires);
         ref var batchState = ref MemoryMarshal.GetArrayDataReference(batchExecutionState);
         ref var end = ref Unsafe.Add(ref batchState, batchExecutionState.Length);
         var pathLength = Path.Length;
         var first = true;
 
+        if (response.TransportException is not null)
+        {
+            foreach (var state in batchExecutionState)
+            {
+                CreateTransportErrors(
+                    response.TransportException,
+                    context.Result,
+                    context.ErrorHandler,
+                    state.SelectionSetResult,
+                    RootSelections,
+                    subgraphName,
+                    context.ShowDebugInfo);
+            }
+        }
+
         while (Unsafe.IsAddressLessThan(ref batchState, ref end))
         {
             if (first)

src/HotChocolate/Fusion/src/Core/Execution/Nodes/ResolverNodeBase.Config.cs

@@ -2,6 +2,7 @@
 using System.Runtime.CompilerServices;
 using HotChocolate.Execution.Processing;
 using HotChocolate.Fusion.Clients;
+using HotChocolate.Fusion.Planning;
 using HotChocolate.Fusion.Utilities;
 using HotChocolate.Language;
 
@@ -31,6 +32,9 @@ internal readonly ref struct Config
         /// <param name="selectionSet">
         /// The selection set for which this request provides a patch.
         /// </param>
+        /// <param name="rootSelections">
+        /// The root selections of this subgraph request.
+        /// </param>
         /// <param name="provides">
         /// The variables that this resolver node will provide.
         /// </param>
@@ -51,6 +55,7 @@ public Config(
             DocumentNode document,
             ISelection? parent,
             ISelectionSet selectionSet,
+            List<RootSelection> rootSelections,
             IEnumerable<string> provides,
             IEnumerable<string> requires,
             IEnumerable<string> forwardedVariables,
@@ -63,6 +68,7 @@ public Config(
             SubgraphName = subgraphName;
             Document = document.ToString(false);
             Parent = parent;
+            RootSelections = rootSelections;
             SelectionSet = Unsafe.As<SelectionSet>(selectionSet);
             Provides = CollectionUtils.CopyToArray(provides, ref buffer, ref usedCapacity);
             Requires = CollectionUtils.CopyToArray(requires, ref buffer, ref usedCapacity);
@@ -94,6 +100,11 @@ public Config(
         /// </summary>
         public ISelection? Parent { get; }
 
+        /// <summary>
+        /// Gets the root selections of this subgraph request.
+        /// </summary>
+        public List<RootSelection> RootSelections { get; }
+
         /// <summary>
         /// Gets the selection set for which this request provides a patch.
         /// </summary>