feat: pass abortSignal to resolvers (#4261)

this allows e.g. passing the signal to fetch

Note: the `abortSignal` is now the fifth argument to a GraphQLFieldResolverFn. If no resolver if provided, and the parent is an object with a key for the field name with a value that is a function, the `abortSignal` will be the fourth argument, as in the included test, with the `parent` accessible via the `this` keyword.

src/execution/__tests__/abort-signal-test.ts

@@ -109,6 +109,53 @@ describe('Execute: Cancellation', () => {
     });
   });
 
+  it('should provide access to the abort signal within resolvers', async () => {
+    const abortController = new AbortController();
+    const document = parse(`
+      query {
+        todo {
+          id
+        }
+      }
+    `);
+
+    const cancellableAsyncFn = async (abortSignal: AbortSignal) => {
+      await resolveOnNextTick();
+      abortSignal.throwIfAborted();
+    };
+
+    const resultPromise = execute({
+      document,
+      schema,
+      abortSignal: abortController.signal,
+      rootValue: {
+        todo: {
+          id: (_args: any, _context: any, _info: any, signal: AbortSignal) =>
+            cancellableAsyncFn(signal),
+        },
+      },
+    });
+
+    abortController.abort();
+
+    const result = await resultPromise;
+
+    expectJSON(result).toDeepEqual({
+      data: {
+        todo: {
+          id: null,
+        },
+      },
+      errors: [
+        {
+          message: 'This operation was aborted',
+          path: ['todo', 'id'],
+          locations: [{ line: 4, column: 11 }],
+        },
+      ],
+    });
+  });
+
   it('should stop the execution when aborted during object field completion with a custom error', async () => {
     const abortController = new AbortController();
     const document = parse(`

src/execution/execute.ts

@@ -798,7 +798,7 @@ function executeField(
   deferMap: ReadonlyMap<DeferUsage, DeferredFragmentRecord> | undefined,
 ): PromiseOrValue<GraphQLWrappedResult<unknown>> | undefined {
   const validatedExecutionArgs = exeContext.validatedExecutionArgs;
-  const { schema, contextValue, variableValues, hideSuggestions } =
+  const { schema, contextValue, variableValues, hideSuggestions, abortSignal } =
     validatedExecutionArgs;
   const fieldName = fieldDetailsList[0].node.name.value;
   const fieldDef = schema.getField(parentType, fieldName);
@@ -833,7 +833,7 @@ function executeField(
     // 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 = resolveFn(source, args, contextValue, info);
+    const result = resolveFn(source, args, contextValue, info, abortSignal);
 
     if (isPromise(result)) {
       return completePromisedValue(
@@ -1955,12 +1955,12 @@ export const defaultTypeResolver: GraphQLTypeResolver<unknown, unknown> =
  * of calling that function while passing along args and context value.
  */
 export const defaultFieldResolver: GraphQLFieldResolver<unknown, unknown> =
-  function (source: any, args, contextValue, info) {
+  function (source: any, args, contextValue, info, abortSignal) {
     // ensure source is a value for which property access is acceptable.
     if (isObjectLike(source) || typeof source === 'function') {
       const property = source[info.fieldName];
       if (typeof property === 'function') {
-        return source[info.fieldName](args, contextValue, info);
+        return source[info.fieldName](args, contextValue, info, abortSignal);
       }
       return property;
     }
@@ -2115,6 +2115,7 @@ function executeSubscription(
     operation,
     variableValues,
     hideSuggestions,
+    abortSignal,
   } = validatedExecutionArgs;
 
   const rootType = schema.getSubscriptionType();
@@ -2180,7 +2181,7 @@ function executeSubscription(
     // 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 = resolveFn(rootValue, args, contextValue, info);
+    const result = resolveFn(rootValue, args, contextValue, info, abortSignal);
 
     if (isPromise(result)) {
       return result

src/type/definition.ts

@@ -990,6 +990,7 @@ export type GraphQLFieldResolver<
   args: TArgs,
   context: TContext,
   info: GraphQLResolveInfo,
+  abortSignal: AbortSignal | undefined,
 ) => TResult;
 
 export interface GraphQLResolveInfo {