Fixed issue with variable forwarding in nested fields.

src/HotChocolate/Fusion/src/Core/Planning/RequestFormatters/RequestDocumentFormatter.cs

@@ -1,3 +1,4 @@
+using System.Collections.Immutable;
 using System.Diagnostics;
 using HotChocolate.Execution.Processing;
 using HotChocolate.Fusion.Metadata;
@@ -55,6 +56,17 @@ internal RequestDocument CreateRequestDocument(
 
             rootSelectionSetNode = new SelectionSetNode(new[] { rootResolver });
             path = p;
+
+            var variables =
+                context.Operation.Definition.VariableDefinitions.ToImmutableDictionary(v => v.Variable.Name.Value);
+            var variablesToForward = ExtractVariablesToForward(variables, rootSelectionSetNode.Selections)
+                .Distinct()
+                .Where(v => !context.ForwardedVariables.Contains(v))
+                .ToArray();
+            foreach (var variable in variablesToForward)
+            {
+                context.ForwardedVariables.Add(variable);
+            }
         }
 
         var operationDefinitionNode = new OperationDefinitionNode(
@@ -73,6 +85,42 @@ internal RequestDocument CreateRequestDocument(
             path);
     }
 
+    protected static IEnumerable<VariableDefinitionNode> ExtractVariablesToForward(
+        IReadOnlyDictionary<string, VariableDefinitionNode> globalVariables,
+        IEnumerable<ISelectionNode> selections)
+    {
+        foreach (var selection in selections)
+        {
+            if (selection is FieldNode fieldNode)
+            {
+                foreach (var toForward in fieldNode.Arguments.Where(a => globalVariables.ContainsKey(a.Name.Value)))
+                {
+                    var definition = globalVariables[toForward.Name.Value];
+                    yield return definition;
+                }
+
+                if (fieldNode.SelectionSet == null) continue;
+
+                foreach (var toForward in ExtractVariablesToForward(globalVariables,
+                             fieldNode.SelectionSet.Selections))
+                {
+                    yield return toForward;
+                }
+            }
+
+            if (selection is InlineFragmentNode inlineFragment)
+            {
+                if (inlineFragment.SelectionSet == null) continue;
+
+                foreach (var toForward in ExtractVariablesToForward(globalVariables,
+                             inlineFragment.SelectionSet.Selections))
+                {
+                    yield return toForward;
+                }
+            }
+        }
+    }
+
     protected virtual SelectionSetNode CreateRootSelectionSetNode(
         QueryPlanContext context,
         SelectionExecutionStep executionStep)

src/HotChocolate/Fusion/test/Core.Tests/RequestPlannerTests.cs

@@ -931,7 +931,7 @@ ... on Patient1 {
         snapshot.Add(result.QueryPlan, nameof(result.QueryPlan));
         await snapshot.MatchAsync();
     }
-    
+
     [Fact]
     public async Task Query_Plan_24_Field_Requirement_And_Fields_In_Context()
     {
@@ -978,6 +978,44 @@ query Requires {
         await snapshot.MatchAsync();
     }
 
+
+    [Fact]
+    public async Task Query_Plan_25_Variables_Are_Passed_Through()
+    {
+        // arrange
+        using var demoProject = await DemoProject.CreateAsync();
+
+        var fusionGraph = await new FusionGraphComposer().ComposeAsync(
+            new[]
+            {
+                demoProject.Appointment.ToConfiguration(),
+                demoProject.Patient1.ToConfiguration(),
+            },
+            new FusionFeatureCollection(FusionFeatures.NodeField));
+
+        // act
+        var result = await CreateQueryPlanAsync(
+            fusionGraph,
+            """
+            query Appointments($first: Int!) {
+              patientById(patientId: 1) {
+                name
+                appointments(first: $first) {
+                    nodes {
+                        id
+                    }
+                }
+              }
+            }
+            """);
+
+        // assert
+        var snapshot = new Snapshot();
+        snapshot.Add(result.UserRequest, nameof(result.UserRequest));
+        snapshot.Add(result.QueryPlan, nameof(result.QueryPlan));
+        await snapshot.MatchAsync();
+    }
+
     private static async Task<(DocumentNode UserRequest, QueryPlan QueryPlan)> CreateQueryPlanAsync(
         Skimmed.Schema fusionGraph,
         [StringSyntax("graphql")] string query)

src/HotChocolate/Fusion/test/Core.Tests/__snapshots__/RequestPlannerTests.Query_Plan_25_Variables_Are_Passed_Through.snap

@@ -0,0 +1,63 @@
+UserRequest
+---------------
+query Appointments($first: Int!) {
+  patientById(patientId: 1) {
+    name
+    appointments(first: $first) {
+      nodes {
+        id
+      }
+    }
+  }
+}
+---------------
+
+QueryPlan
+---------------
+{
+  "document": "query Appointments($first: Int!) { patientById(patientId: 1) { name appointments(first: $first) { nodes { id } } } }",
+  "operation": "Appointments",
+  "rootNode": {
+    "type": "Sequence",
+    "nodes": [
+      {
+        "type": "Resolve",
+        "subgraph": "Patient1",
+        "document": "query Appointments_1 { patientById(patientId: 1) { name __fusion_exports__1: id } }",
+        "selectionSetId": 0
+      },
+      {
+        "type": "Compose",
+        "selectionSetIds": [
+          0
+        ]
+      },
+      {
+        "type": "Resolve",
+        "subgraph": "Appointment",
+        "document": "query Appointments_2($__fusion_exports__1: ID!, $first: Int!) { node(id: $__fusion_exports__1) { ... on Patient1 { appointments(first: $first) { nodes { id } } } } }",
+        "selectionSetId": 1,
+        "path": [
+          "node"
+        ],
+        "requires": [
+          {
+            "variable": "__fusion_exports__1"
+          }
+        ],
+        "forwardedVariables": [
+          {
+            "variable": "first"
+          }
+        ]
+      },
+      {
+        "type": "Compose",
+        "selectionSetIds": [
+          1
+        ]
+      }
+    ]
+  }
+}
+---------------

src/HotChocolate/Fusion/test/Shared/Appointments/AppointmentQuery.cs

@@ -29,4 +29,26 @@ public IEnumerable<Appointment> Appointments()
             return null;
         }
     }
+
+    [NodeResolver]
+    public Patient1? GetPatient(int id)
+    {
+        if (id == 1)
+        {
+            return new Patient1()
+            {
+                Id = 1
+            };
+        }
+        if (id == 2)
+        {
+            return new Patient1()
+            {
+                Id = 2
+            };
+        }
+
+        return null;
+
+    }
 }

src/HotChocolate/Fusion/test/Shared/Appointments/Patient1.cs

@@ -1,8 +1,17 @@
+using HotChocolate.Types;
 using HotChocolate.Types.Relay;
 
 namespace HotChocolate.Fusion.Shared.Appointments;
 
 public class Patient1 : IPatient
 {
     [ID<Patient1>] public int Id { get; set;}
+
+    [UsePaging]
+    public IEnumerable<Appointment> Appointments => new List<Appointment>()
+    {
+        new Appointment(),
+        new Appointment(),
+        new Appointment(),
+    };
 }