[Fusion] Fix the operation planner dropping requirement chains

src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Nodes/IncrementalPlan.cs

@@ -7,6 +7,12 @@ namespace HotChocolate.Fusion.Execution.Nodes;
 /// </summary>
 public sealed class IncrementalPlan : IOperationPlan
 {
+    /// <summary>
+    /// The <see cref="ParentNodeId"/> of a plan anchored at the operation root of an
+    /// enclosing plan that has no execution node.
+    /// </summary>
+    public const int NoParentNodeId = 0;
+
     private readonly ExecutionNode?[] _nodesById;
 
     /// <summary>
@@ -88,7 +94,8 @@ public IncrementalPlan(
     /// Gets the <see cref="ExecutionNode.Id"/> of the node that produces the
     /// result object where this incremental plan is anchored. The identifier is
     /// scoped to the root <see cref="OperationPlan"/> for top-level plans, or
-    /// to the enclosing <see cref="IncrementalPlan"/> for nested plans.
+    /// to the enclosing <see cref="IncrementalPlan"/> for nested plans. The value is
+    /// <see cref="NoParentNodeId"/> when the enclosing plan has no execution node.
     /// </summary>
     public int ParentNodeId { get; internal set; }
 

src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Nodes/Serialization/JsonOperationPlanFormatter.cs

@@ -28,7 +28,7 @@ public sealed class JsonOperationPlanFormatter(JsonWriterOptions? options = null
     /// <summary>
     /// The version of the operation plan JSON format written by this formatter.
     /// </summary>
-    private const string FormatVersion = "1.0.0";
+    private const string FormatVersion = "1.1.0";
 
     private readonly JsonWriterOptions _writerOptions = options ?? new JsonWriterOptions
     {

src/HotChocolate/Fusion/src/Fusion.Execution/Execution/ThrowHelper.cs

@@ -1,5 +1,6 @@
 using System.Text.Json;
 using HotChocolate.Execution;
+using HotChocolate.Fusion.Planning;
 using HotChocolate.Fusion.Properties;
 using HotChocolate.Language;
 
@@ -22,6 +23,16 @@ public static InvalidOperationException IncrementalPlanParentNotFound(SelectionP
             FusionExecutionResources.OperationPlan_IncrementalPlanParentNotFound,
             path));
 
+    public static InvalidOperationException DeferredPlanNotFound(SelectionPath path)
+        => new($"No plan was found for the @defer fragment at path '{path}'.");
+
+    public static OperationPlannerGuardrailException PlanningGuardrailExceeded(
+        string operationId,
+        OperationPlannerGuardrailReason reason,
+        long limit,
+        long observed)
+        => new(operationId, reason, limit, observed);
+
     public static InvalidOperationException MissingBatchResult(int operationId)
         => new(string.Format(
             FusionExecutionResources.OperationBatchExecutionNode_MissingBatchResult,