From 8e4af17d11cc93fca88f709bc9bdeb1bf4f571be Mon Sep 17 00:00:00 2001
From: Yaacov Rydzinski <yaacovCR@gmail.com>
Date: Thu, 30 Apr 2026 22:25:53 +0300
Subject: [PATCH] refactor: add executionMode/serially argument to
 executeRootSelectionSet

Motivation:
more closely matches spec.
allows executeSubscriptionEvent to set without re-checking operation
drops comment/handling regarding subscribe/execute integration which may never happen.

For now, the argument is only within the Executor, so that non-spec compliant combinations of operations and execution mode are disallowed.
---
 src/execution/Executor.ts                     | 35 ++++++-------------
 .../ExecutorThrowingOnIncremental.ts          |  4 +--
 src/execution/execute.ts                      |  4 ++-
 .../incremental/IncrementalExecutor.ts        |  6 ++--
 4 files changed, 19 insertions(+), 30 deletions(-)

diff --git a/src/execution/Executor.ts b/src/execution/Executor.ts
index c2312167d2..4d7145d050 100644
--- a/src/execution/Executor.ts
+++ b/src/execution/Executor.ts
@@ -272,9 +272,9 @@ export class Executor<
     this.promiseAll = promiseAll;
   }
 
-  executeRootSelectionSet(): PromiseOrValue<
-    ExecutionResult | TAlternativeInitialResponse
-  > {
+  executeRootSelectionSet(
+    serially?: boolean,
+  ): PromiseOrValue<ExecutionResult | TAlternativeInitialResponse> {
     const externalAbortSignal = this.validatedExecutionArgs.externalAbortSignal;
     let removeExternalAbortListener: (() => void) | undefined;
     if (externalAbortSignal) {
@@ -322,10 +322,10 @@ export class Executor<
       );
 
       result = this.executeCollectedRootFields(
-        operation.operation,
         rootType,
         rootValue,
         groupedFieldSet,
+        serially ?? operationType === OperationTypeNode.MUTATION,
         newDeferUsages,
       );
 
@@ -420,56 +420,43 @@ export class Executor<
   }
 
   executeCollectedRootFields(
-    operation: OperationTypeNode,
     rootType: GraphQLObjectType,
     rootValue: unknown,
     originalGroupedFieldSet: GroupedFieldSet,
+    serially: boolean,
     _newDeferUsages: ReadonlyArray<DeferUsage>,
   ): PromiseOrValue<ObjMap<unknown>> {
     return this.executeRootGroupedFieldSet(
-      operation,
       rootType,
       rootValue,
       originalGroupedFieldSet,
+      serially,
       undefined,
     );
   }
 
   executeRootGroupedFieldSet(
-    operation: OperationTypeNode,
     rootType: GraphQLObjectType,
     rootValue: unknown,
     groupedFieldSet: GroupedFieldSet,
+    serially: boolean,
     positionContext?: TPositionContext,
   ): PromiseOrValue<ObjMap<unknown>> {
-    switch (operation) {
-      case OperationTypeNode.QUERY:
-        return this.executeFields(
+    return serially
+      ? this.executeFieldsSerially(
           rootType,
           rootValue,
           undefined,
           groupedFieldSet,
           positionContext,
-        );
-      case OperationTypeNode.MUTATION:
-        return this.executeFieldsSerially(
-          rootType,
-          rootValue,
-          undefined,
-          groupedFieldSet,
-          positionContext,
-        );
-      case OperationTypeNode.SUBSCRIPTION:
-        // TODO: deprecate `subscribe` and move all logic here
-        // Temporary solution until we finish merging execute and subscribe together
-        return this.executeFields(
+        )
+      : this.executeFields(
           rootType,
           rootValue,
           undefined,
           groupedFieldSet,
           positionContext,
         );
-    }
   }
 
   /**
diff --git a/src/execution/ExecutorThrowingOnIncremental.ts b/src/execution/ExecutorThrowingOnIncremental.ts
index 4983e61c97..990f0e68f3 100644
--- a/src/execution/ExecutorThrowingOnIncremental.ts
+++ b/src/execution/ExecutorThrowingOnIncremental.ts
@@ -25,10 +25,10 @@ const UNEXPECTED_MULTIPLE_PAYLOADS =
 /** @internal */
 export class ExecutorThrowingOnIncremental extends Executor {
   override executeCollectedRootFields(
-    operation: OperationTypeNode,
     rootType: GraphQLObjectType,
     rootValue: unknown,
     originalGroupedFieldSet: GroupedFieldSet,
+    serially: boolean,
     newDeferUsages: ReadonlyArray<DeferUsage>,
   ): PromiseOrValue<ObjMap<unknown>> {
     if (newDeferUsages.length > 0) {
@@ -42,10 +42,10 @@ export class ExecutorThrowingOnIncremental extends Executor {
       throw reason;
     }
     return this.executeRootGroupedFieldSet(
-      operation,
       rootType,
       rootValue,
       originalGroupedFieldSet,
+      serially,
       undefined,
     );
   }
diff --git a/src/execution/execute.ts b/src/execution/execute.ts
index c82e2e0bc2..988142cb3d 100644
--- a/src/execution/execute.ts
+++ b/src/execution/execute.ts
@@ -183,7 +183,9 @@ export function executeSync(args: ExecutionArgs): ExecutionResult {
 export function executeSubscriptionEvent(
   validatedExecutionArgs: ValidatedSubscriptionArgs,
 ): PromiseOrValue<ExecutionResult> {
-  return executeRootSelectionSet(validatedExecutionArgs);
+  return new ExecutorThrowingOnIncremental(
+    validatedExecutionArgs,
+  ).executeRootSelectionSet(false);
 }
 
 /**
diff --git a/src/execution/incremental/IncrementalExecutor.ts b/src/execution/incremental/IncrementalExecutor.ts
index 00b4264624..0622818f82 100644
--- a/src/execution/incremental/IncrementalExecutor.ts
+++ b/src/execution/incremental/IncrementalExecutor.ts
@@ -362,18 +362,18 @@ export class IncrementalExecutor<
   }
 
   override executeCollectedRootFields(
-    operation: OperationTypeNode,
     rootType: GraphQLObjectType,
     rootValue: unknown,
     originalGroupedFieldSet: GroupedFieldSet,
+    serially: boolean,
     newDeferUsages: ReadonlyArray<DeferUsage>,
   ): PromiseOrValue<ObjMap<unknown>> {
     if (newDeferUsages.length === 0) {
       return this.executeRootGroupedFieldSet(
-        operation,
         rootType,
         rootValue,
         originalGroupedFieldSet,
+        serially,
         undefined,
       );
     }
@@ -391,10 +391,10 @@ export class IncrementalExecutor<
       this.buildRootExecutionPlan(originalGroupedFieldSet);
 
     const data = this.executeRootGroupedFieldSet(
-      operation,
       rootType,
       rootValue,
       groupedFieldSet,
+      serially,
       newDeliveryGroupMap,
     );