ChilliCream · tobias-tengler · Apr 8, 2026 · Apr 8, 2026
diff --git a/src/HotChocolate/AspNetCore/test/AspNetCore.Tests.Utilities/UploadQuery.cs b/src/HotChocolate/AspNetCore/test/AspNetCore.Tests.Utilities/UploadQuery.cs
@@ -40,9 +40,26 @@ public async Task<string> ListUpload(
         return await sr.ReadToEndAsync();
     }
 
-    public async Task<string> OptionalUpload([GraphQLType(typeof(UploadType))] Optional<IFile> file)
+    public async Task<string?> NullableUpload(IFile? file)
     {
-        await using var stream = file.Value!.OpenReadStream();
+        if (file is null)
+        {
+            return null;
+        }
+
+        await using var stream = file.OpenReadStream();
+        using var sr = new StreamReader(stream, Encoding.UTF8);
+        return await sr.ReadToEndAsync();
+    }
+
+    public async Task<string?> OptionalUpload([GraphQLType(typeof(UploadType))] Optional<IFile> file)
+    {
+        if (!file.HasValue || file.Value is null)
+        {
+            return null;
+        }
+
+        await using var stream = file.Value.OpenReadStream();
         using var sr = new StreamReader(stream, Encoding.UTF8);
         return await sr.ReadToEndAsync();
     }

diff --git a/src/HotChocolate/AspNetCore/test/AspNetCore.Tests/HttpMultipartMiddlewareTests.cs b/src/HotChocolate/AspNetCore/test/AspNetCore.Tests/HttpMultipartMiddlewareTests.cs
@@ -3,13 +3,8 @@
 
 namespace HotChocolate.AspNetCore;
 
-public class HttpMultipartMiddlewareTests : ServerTestBase
+public class HttpMultipartMiddlewareTests(TestServerFactory serverFactory) : ServerTestBase(serverFactory)
 {
-    public HttpMultipartMiddlewareTests(TestServerFactory serverFactory)
-        : base(serverFactory)
-    {
-    }
-
     [Fact]
     public async Task EmptyForm_Test()
     {
@@ -300,6 +295,115 @@ public async Task Upload_Optional_File()
         result.MatchSnapshot();
     }
 
+    [Fact]
+    public async Task Upload_Optional_File_Not_Provided()
+    {
+        // arrange
+        var server = CreateStarWarsServer();
+
+        // act
+        var result = await server.PostAsync(
+            new ClientQueryRequest
+            {
+                Query = @"
+                    query ($upload: Upload) {
+                        optionalUpload(file: $upload)
+                    }",
+                Variables = new Dictionary<string, object?>
+                {
+                    { "upload", null }
+                }
+            },
+            "/upload");
+
+        // assert
+        result.MatchInlineSnapshot(
+            """
+            {
+              "ContentType": "application/graphql-response+json; charset=utf-8",
+              "StatusCode": "OK",
+              "Data": {
+                "optionalUpload": null
+              },
+              "Errors": null,
+              "Extensions": null
+            }
+            """);
+    }
+
+    [Fact]
+    public async Task Upload_Nullable_File()
+    {
+        // arrange
+        var server = CreateStarWarsServer();
+
+        const string query = @"
+                query ($upload: Upload) {
+                    nullableUpload(file: $upload)
+                }";
+
+        var request = JsonConvert.SerializeObject(
+            new ClientQueryRequest
+            {
+                Query = query,
+                Variables = new Dictionary<string, object?>
+                {
+                    { "upload", null }
+                }
+            });
+
+        // act
+        var form = new MultipartFormDataContent
+        {
+            { new StringContent(request), "operations" },
+            { new StringContent("{ \"1\": [\"variables.upload\"] }"), "map" },
+            { new StringContent("abc"), "1", "foo.bar" }
+        };
+
+        form.Headers.Add(HttpHeaderKeys.Preflight, "1");
+
+        var result = await server.PostMultipartAsync(form, path: "/upload");
+
+        // assert
+        result.MatchSnapshot();
+    }
+
+    [Fact]
+    public async Task Upload_Nullable_File_Not_Provided()
+    {
+        // arrange
+        var server = CreateStarWarsServer();
+
+        // act
+        var result = await server.PostAsync(
+            new ClientQueryRequest
+            {
+                Query = @"
+                    query ($upload: Upload) {
+                        nullableUpload(file: $upload)
+                    }",
+                Variables = new Dictionary<string, object?>
+                {
+                    { "upload", null }
+                }
+            },
+            "/upload");
+
+        // assert
+        result.MatchInlineSnapshot(
+            """
+            {
+              "ContentType": "application/graphql-response+json; charset=utf-8",
+              "StatusCode": "OK",
+              "Data": {
+                "nullableUpload": null
+              },
+              "Errors": null,
+              "Extensions": null
+            }
+            """);
+    }
+
     [Fact]
     public async Task Upload_Optional_File_In_InputObject()
     {

diff --git a/...est/AspNetCore.Tests/__snapshots__/HttpMultipartMiddlewareTests.Upload_Nullable_File.snap b/...est/AspNetCore.Tests/__snapshots__/HttpMultipartMiddlewareTests.Upload_Nullable_File.snap
@@ -0,0 +1,9 @@
+{
+  "ContentType": "application/graphql-response+json; charset=utf-8",
+  "StatusCode": "OK",
+  "Data": {
+    "nullableUpload": "abc"
+  },
+  "Errors": null,
+  "Extensions": null
+}
diff --git a/src/HotChocolate/Fusion/src/Fusion.Connectors.InMemory/InMemorySourceSchemaClient.cs b/src/HotChocolate/Fusion/src/Fusion.Connectors.InMemory/InMemorySourceSchemaClient.cs
@@ -225,10 +225,11 @@ private static IOperationRequest BuildOperationRequest(
     {
         IFeatureCollection? features = null;
 
-        if (request.RequiresFileUpload)
+        if (request.RequiresFileUpload
+            && context.RequestContext.Features.Get<IFileLookup>() is { } fileLookup)
         {
             features = new FeatureCollection();
-            features.Set(context.RequestContext.Features.GetRequired<IFileLookup>());
+            features.Set(fileLookup);
         }
 
         if (request.Variables.Length == 0)

diff --git a/src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Clients/SourceSchemaHttpClient.cs b/src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Clients/SourceSchemaHttpClient.cs
@@ -347,7 +347,8 @@ private GraphQLHttpRequest CreateHttpBatchRequest(
         bool requiresFileUpload,
         ref ChunkedArrayWriter? buffer)
     {
-        if (requiresFileUpload)
+        if (requiresFileUpload
+            && context.RequestContext.Features.Get<IFileLookup>() is { } fileLookup)
         {
             var capacity = originalRequests.Length;
 
@@ -361,7 +362,6 @@ private GraphQLHttpRequest CreateHttpBatchRequest(
 
             var batchRequests = ImmutableArray.CreateBuilder<IOperationRequest>(capacity);
             var fileEntries = ImmutableArray.CreateBuilder<FileEntry>();
-            var fileLookup = context.RequestContext.Features.GetRequired<IFileLookup>();
             buffer ??= new ChunkedArrayWriter();
             var i = 0;
 
@@ -486,10 +486,10 @@ private static OperationRequest CreateSingleRequest(
             ? VariableValues.Empty
             : originalRequest.Variables[0];
 
-        if (originalRequest.RequiresFileUpload)
+        if (originalRequest.RequiresFileUpload
+            && context.RequestContext.Features.Get<IFileLookup>() is { } fileLookup)
         {
             writer ??= new ChunkedArrayWriter();
-            var fileLookup = context.RequestContext.Features.GetRequired<IFileLookup>();
             var (cleanedJson, fileMap) = FileEntryBuilder.Build(writer, variables.Values, fileLookup);
 
             return new OperationRequest(
@@ -535,10 +535,10 @@ private static OperationBatchRequest CreateOperationBatchRequest(
         SourceSchemaClientRequest originalRequest,
         ref ChunkedArrayWriter? writer)
     {
-        if (originalRequest.RequiresFileUpload)
+        if (originalRequest.RequiresFileUpload
+            && context.RequestContext.Features.Get<IFileLookup>() is { } fileLookup)
         {
             writer ??= new ChunkedArrayWriter();
-            var fileLookup = context.RequestContext.Features.GetRequired<IFileLookup>();
             var fileEntries = ImmutableArray.CreateBuilder<FileEntry>();
             var requests = new OperationRequest[originalRequest.Variables.Length];
 

diff --git a/src/HotChocolate/Fusion/src/Fusion.Execution/Execution/JsonVariableCoercion.cs b/src/HotChocolate/Fusion/src/Fusion.Execution/Execution/JsonVariableCoercion.cs
@@ -345,7 +345,8 @@ private readonly bool TryParseScalar(
         {
             if (element.ValueKind is JsonValueKind.String
                 && element.GetString() is { Length: > 0 } fileKey
-                && _context.Features.GetRequired<IFileLookup>().TryGetFile(fileKey, out _))
+                && _context.Features.Get<IFileLookup>() is { } fileLookup
+                && fileLookup.TryGetFile(fileKey, out _))
             {
                 value = new StringValueNode($"$.file({fileKey})");
                 error = null;

diff --git a/src/HotChocolate/Fusion/test/Fusion.AspNetCore.Tests/FileUploadTests.cs b/src/HotChocolate/Fusion/test/Fusion.AspNetCore.Tests/FileUploadTests.cs
@@ -317,6 +317,97 @@ public async Task Upload_List_Of_Files_In_Input_Object_Inline()
         await MatchSnapshotAsync(gateway, operation, result, rawRequest: rawRequest);
     }
 
+    [Fact]
+    public async Task Upload_Nullable_File_Not_Provided()
+    {
+        // arrange
+        using var server1 = CreateSourceSchema(
+            "A",
+            b => b.AddQueryType<SourceSchema1.Query>().AddUploadType());
+
+        using var gateway = await CreateCompositeSchemaAsync(
+        [
+            ("A", server1)
+        ]);
+
+        // act
+        using var client = GraphQLHttpClient.Create(gateway.CreateClient());
+
+        var operation = new OperationRequest(
+            """
+            query ($file: Upload) {
+              nullableUpload(file: $file) {
+                fileName
+                contentType
+                content
+              }
+            }
+            """,
+            variables: new Dictionary<string, object?>
+            {
+                ["file"] = null
+            } );
+
+        var request = new GraphQLHttpRequest(operation, new Uri("http://localhost:5000/graphql"))
+        {
+            Method = GraphQLHttpMethod.Post
+        };
+
+        // act
+        var result = await client.SendAsync(request);
+
+        // assert
+        await MatchSnapshotAsync(gateway, operation, result);
+    }
+
+    [Fact]
+    public async Task Upload_Nullable_File()
+    {
+        // arrange
+        using var server1 = CreateSourceSchema(
+            "A",
+            b => b.AddQueryType<SourceSchema1.Query>().AddUploadType());
+
+        using var gateway = await CreateCompositeSchemaAsync(
+        [
+            ("A", server1)
+        ]);
+
+        // act
+        using var client = GraphQLHttpClient.Create(gateway.CreateClient());
+
+        var stream = new MemoryStream("abc"u8.ToArray());
+
+        var operation = new OperationRequest(
+            """
+            query ($file: Upload) {
+              nullableUpload(file: $file) {
+                fileName
+                contentType
+                content
+              }
+            }
+            """,
+            variables: new Dictionary<string, object?>
+            {
+                ["file"] = new FileReference(() => stream, "test.txt", "text/plain")
+            });
+
+        RawRequest? rawRequest = null;
+        var request = new GraphQLHttpRequest(operation, new Uri("http://localhost:5000/graphql"))
+        {
+            Method = GraphQLHttpMethod.Post,
+            EnableFileUploads = true,
+            OnMessageCreated = (_, request, _) => rawRequest = GetRawRequest(request)
+        };
+
+        // act
+        var result = await client.SendAsync(request);
+
+        // assert
+        await MatchSnapshotAsync(gateway, operation, result, rawRequest: rawRequest);
+    }
+
     private static RawRequest GetRawRequest(HttpRequestMessage requestMessage)
     {
         if (requestMessage.Content is not { } content)
@@ -349,6 +440,16 @@ public class Query
         {
             public async Task<FileUploadResult> SingleUpload(IFile file) => await ReadFileAsync(file);
 
+            public async Task<FileUploadResult?> NullableUpload(IFile? file)
+            {
+                if (file is null)
+                {
+                    return null;
+                }
+
+                return await ReadFileAsync(file);
+            }
+
             public async Task<FileUploadResult> SingleUploadWithInput(FileInput input)
                 => await ReadFileAsync(input.File);
 

diff --git a/...sion/test/Fusion.AspNetCore.Tests/__snapshots__/FileUploadTests.Upload_List_Of_Files.yaml b/...sion/test/Fusion.AspNetCore.Tests/__snapshots__/FileUploadTests.Upload_List_Of_Files.yaml
@@ -56,6 +56,7 @@ sourceSchemas:
 
       type Query {
         singleUpload(file: Upload!): FileUploadResult!
+        nullableUpload(file: Upload): FileUploadResult
         singleUploadWithInput(input: FileInput!): FileUploadResult!
         multiUpload(files: [Upload!]!): [FileUploadResult!]!
         multiUploadWithInput(input: FilesInput!): [FileUploadResult!]!

diff --git a/....AspNetCore.Tests/__snapshots__/FileUploadTests.Upload_List_Of_Files_In_Input_Object.yaml b/....AspNetCore.Tests/__snapshots__/FileUploadTests.Upload_List_Of_Files_In_Input_Object.yaml
@@ -56,6 +56,7 @@ sourceSchemas:
 
       type Query {
         singleUpload(file: Upload!): FileUploadResult!
+        nullableUpload(file: Upload): FileUploadResult
         singleUploadWithInput(input: FileInput!): FileUploadResult!
         multiUpload(files: [Upload!]!): [FileUploadResult!]!
         multiUploadWithInput(input: FilesInput!): [FileUploadResult!]!

diff --git a/...Core.Tests/__snapshots__/FileUploadTests.Upload_List_Of_Files_In_Input_Object_Inline.yaml b/...Core.Tests/__snapshots__/FileUploadTests.Upload_List_Of_Files_In_Input_Object_Inline.yaml
@@ -56,6 +56,7 @@ sourceSchemas:
 
       type Query {
         singleUpload(file: Upload!): FileUploadResult!
+        nullableUpload(file: Upload): FileUploadResult
         singleUploadWithInput(input: FileInput!): FileUploadResult!
         multiUpload(files: [Upload!]!): [FileUploadResult!]!
         multiUploadWithInput(input: FilesInput!): [FileUploadResult!]!