ref(perf): cache publish decision in excutor

Author: logaretm

src/diagnostics.ts

@@ -139,7 +139,7 @@ export function enableDiagnosticsChannel(dc: MinimalDiagnosticsChannel): void {
  *
  * @internal
  */
-function shouldTrace(
+export function shouldTrace(
   channel: MinimalTracingChannel | undefined,
 ): channel is MinimalTracingChannel {
   // eslint-disable-next-line @typescript-eslint/no-unnecessary-boolean-literal-compare

src/execution/Executor.ts

@@ -44,7 +44,8 @@ import {
 } from '../type/definition.js';
 import type { GraphQLSchema } from '../type/schema.js';
 
-import { maybeTraceMixed } from '../diagnostics.js';
+import type { MinimalTracingChannel } from '../diagnostics.js';
+import { getChannels, maybeTraceMixed, shouldTrace } from '../diagnostics.js';
 
 import { AbortedGraphQLExecutionError } from './AbortedGraphQLExecutionError.js';
 import { withCancellation } from './cancellablePromise.js';
@@ -245,6 +246,12 @@ export class Executor<
     values: ReadonlyArray<PromiseOrValue<T>>,
   ) => Promise<Array<T>>;
 
+  // Resolved once per Executor so the per-field gate in `executeField` is a
+  // single member read + null check, not a `getChannels()?.resolve` walk +
+  // `hasSubscribers` read on every resolution. Undefined when diagnostics
+  // are off or nobody is listening at construction time.
+  _resolveChannel: MinimalTracingChannel | undefined;
+
   constructor(
     validatedExecutionArgs: ValidatedExecutionArgs,
     sharedExecutionContext?: SharedExecutionContext,
@@ -254,6 +261,11 @@ export class Executor<
     this.abortReason = defaultAbortReason;
     this.collectedErrors = new CollectedErrors();
 
+    const resolveChannel = getChannels()?.resolve;
+    this._resolveChannel = shouldTrace(resolveChannel)
+      ? resolveChannel
+      : undefined;
+
     if (sharedExecutionContext === undefined) {
       this.resolverAbortController = new AbortController();
       this.sharedExecutionContext = createSharedExecutionContext(
@@ -615,11 +627,13 @@ export class Executor<
       // The resolve function's optional third argument is a context value that
       // is provided to every resolve function within an execution. It is commonly
       // used to represent an authenticated user, or request-specific caches.
-      const result = maybeTraceMixed(
-        'resolve',
-        () => buildResolveCtx(info, args, fieldDef.resolve === undefined),
-        () => resolveFn(source, args, contextValue, info),
-      );
+      const result = this._resolveChannel
+        ? maybeTraceMixed(
+            'resolve',
+            () => buildResolveCtx(info, args, fieldDef.resolve === undefined),
+            () => resolveFn(source, args, contextValue, info),
+          )
+        : resolveFn(source, args, contextValue, info);
 
       if (isPromiseLike(result)) {
         return this.completePromisedValue(