Added support for variables to new operation planner.

src/HotChocolate/Fusion-vnext/src/Fusion.Execution/Planning/Nodes/FieldPlanNode.cs

@@ -1,6 +1,6 @@
-using System.Collections.Immutable;
 using System.Diagnostics;
 using HotChocolate.Fusion.Types;
+using HotChocolate.Fusion.Types.Collections;
 using HotChocolate.Language;
 
 namespace HotChocolate.Fusion.Planning.Nodes;
@@ -11,19 +11,31 @@ public sealed class FieldPlanNode : SelectionPlanNode
 
     public FieldPlanNode(
         FieldNode fieldNode,
-        CompositeOutputField field)
+        OutputFieldInfo field)
         : base(field.Type.NamedType(), fieldNode.SelectionSet?.Selections)
     {
         FieldNode = fieldNode;
         Field = field;
         ResponseName = FieldNode.Alias?.Value ?? field.Name;
+
+        foreach (var argument in fieldNode.Arguments)
+        {
+            AddArgument(new ArgumentAssignment(argument.Name.Value, argument.Value));
+        }
+    }
+
+    public FieldPlanNode(
+        FieldNode fieldNode,
+        CompositeOutputField field)
+        : this(fieldNode, new OutputFieldInfo(field))
+    {
     }
 
     public string ResponseName { get; }
 
     public FieldNode FieldNode { get; }
 
-    public CompositeOutputField Field { get; }
+    public OutputFieldInfo Field { get; }
 
     public IReadOnlyList<ArgumentAssignment> Arguments
         => _arguments ?? (IReadOnlyList<ArgumentAssignment>)Array.Empty<ArgumentAssignment>();

src/HotChocolate/Fusion-vnext/src/Fusion.Execution/Planning/Nodes/OperationPlanNode.cs

@@ -8,7 +8,10 @@ namespace HotChocolate.Fusion.Planning.Nodes;
 /// </summary>
 public sealed class OperationPlanNode : SelectionPlanNode, IOperationPlanNodeProvider
 {
+    private static readonly IReadOnlyDictionary<string, VariableDefinitionNode> _emptyVariableMap =
+        new Dictionary<string, VariableDefinitionNode>();
     private List<OperationPlanNode>? _operations;
+    private Dictionary<string, VariableDefinitionNode>? _variables;
 
     public OperationPlanNode(
         string schemaName,
@@ -37,9 +40,18 @@ public OperationPlanNode(
     // todo: variable representations are missing.
     // todo: how to we represent state?
 
+    public IReadOnlyDictionary<string, VariableDefinitionNode> VariableDefinitions
+        => _variables ?? _emptyVariableMap;
+
     public IReadOnlyList<OperationPlanNode> Operations
         => _operations ?? (IReadOnlyList<OperationPlanNode>)Array.Empty<OperationPlanNode>();
 
+    public void AddVariableDefinition(VariableDefinitionNode variable)
+    {
+        ArgumentNullException.ThrowIfNull(variable);
+        (_variables ??= new Dictionary<string, VariableDefinitionNode>()).Add(variable.Variable.Name.Value, variable);
+    }
+
     public void AddOperation(OperationPlanNode operation)
     {
         ArgumentNullException.ThrowIfNull(operation);
@@ -53,7 +65,7 @@ public OperationDefinitionNode ToSyntaxNode()
             null,
             null,
             OperationType.Query,
-            Array.Empty<VariableDefinitionNode>(),
+            _variables?.Values.OrderBy(t => t.Variable.Name.Value).ToArray() ?? [],
             Directives.ToSyntaxNode(),
             Selections.ToSyntaxNode());
     }

src/HotChocolate/Fusion-vnext/src/Fusion.Execution/Planning/Nodes/OutputFieldInfo.cs

@@ -0,0 +1,19 @@
+using System.Collections.Immutable;
+using HotChocolate.Fusion.Types;
+
+namespace HotChocolate.Fusion.Planning.Nodes;
+
+public class OutputFieldInfo(string name, ICompositeType type, ImmutableArray<string> sources)
+{
+    public OutputFieldInfo(CompositeOutputField field)
+        : this(field.Name, field.Type, field.Sources.Schemas)
+    {
+
+    }
+
+    public string Name => name;
+
+    public ICompositeType Type => type;
+
+    public ImmutableArray<string> Sources => sources;
+}