Fix #20972 (#20974)

src/bun.js/modules/NodeUtilTypesModule.cpp

@@ -181,7 +181,7 @@ JSC_DEFINE_HOST_FUNCTION(jsFunctionIsAsyncFunction,
     GET_FIRST_VALUE
 
     auto* function = jsDynamicCast<JSFunction*>(value);
-    if (!function)
+    if (!function || function->isHostFunction())
         return JSValue::encode(jsBoolean(false));
 
     auto* executable = function->jsExecutable();
@@ -207,7 +207,7 @@ JSC_DEFINE_HOST_FUNCTION(jsFunctionIsGeneratorFunction,
 {
     GET_FIRST_VALUE
     auto* function = jsDynamicCast<JSFunction*>(value);
-    if (!function)
+    if (!function || function->isHostFunction())
         return JSValue::encode(jsBoolean(false));
 
     auto* executable = function->jsExecutable();

test/js/node/util/test-util-types.test.js

@@ -253,7 +253,14 @@ test("isAsyncFunction", () => {
     expect(types.isAsyncFunction(fn)).toBeTrue();
   }
 
-  for (let fn of [function normal() {}, function* generatorFn() {}]) {
+  for (let fn of [
+    function normal() {},
+    function* generatorFn() {},
+    function bound() {}.bind(),
+    Bun.sleep, // host function
+    Promise.resolve, // builtin function
+    async function asyncBound() {}.bind(), // node also returns false
+  ]) {
     expect(types.isAsyncFunction(fn)).toBeFalse();
   }
 });
@@ -262,7 +269,15 @@ test("isGeneratorFunction", () => {
     expect(types.isGeneratorFunction(fn)).toBeTrue();
   }
 
-  for (let fn of [function normal() {}, async function asyncFn() {}]) {
+  for (let fn of [
+    function normal() {},
+    async function asyncFn() {},
+    function bound() {}.bind(),
+    Bun.sleep, // host function
+    Promise.resolve, // builtin function
+    function* boundGenerator() {}.bind(), // node also returns false
+    async function* boundAsyncGenerator() {}.bind(), // node also returns false
+  ]) {
     expect(types.isGeneratorFunction(fn)).toBeFalse();
   }
 });

test/no-validate-exceptions.txt

@@ -371,7 +371,6 @@ test/js/node/util/custom-inspect.test.js
 test/js/node/util/mime-api.test.ts
 test/js/node/util/node-inspect-tests/parallel/util-inspect.test.js
 test/js/node/util/parse_args/default-args.test.mjs
-test/js/node/util/test-util-types.test.js
 test/js/node/util/util-callbackify.test.js
 test/js/node/util/util-promisify.test.js
 test/js/node/util/util.test.js