lib: fix AsyncResource.bind not using 'this' from the caller by default

PR-URL: https://github.com/nodejs/node/pull/42177
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Reviewed-By: Bradley Farias <bradley.meck@gmail.com>
Reviewed-By: Bryan English <bryan@bryanenglish.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/async_context.md

@@ -446,6 +446,10 @@ added:
   - v14.8.0
   - v12.19.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/42177
+    description: Changed the default when `thisArg` is undefined to use `this`
+                 from the caller.
   - version: v16.0.0
     pr-url: https://github.com/nodejs/node/pull/36782
     description: Added optional thisArg.
@@ -468,6 +472,10 @@ added:
   - v14.8.0
   - v12.19.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/42177
+    description: Changed the default when `thisArg` is undefined to use `this`
+                 from the caller.
   - version: v16.0.0
     pr-url: https://github.com/nodejs/node/pull/36782
     description: Added optional thisArg.

lib/async_hooks.js

@@ -5,6 +5,7 @@ const {
   ArrayPrototypeIndexOf,
   ArrayPrototypePush,
   ArrayPrototypeSplice,
+  ArrayPrototypeUnshift,
   FunctionPrototypeBind,
   NumberIsSafeInteger,
   ObjectDefineProperties,
@@ -223,15 +224,19 @@ class AsyncResource {
     return this[trigger_async_id_symbol];
   }
 
-  bind(fn, thisArg = this) {
+  bind(fn, thisArg) {
     validateFunction(fn, 'fn');
-    const ret =
-      FunctionPrototypeBind(
-        this.runInAsyncScope,
-        this,
-        fn,
-        thisArg);
-    ObjectDefineProperties(ret, {
+    let bound;
+    if (thisArg === undefined) {
+      const resource = this;
+      bound = function(...args) {
+        ArrayPrototypeUnshift(args, fn, this);
+        return ReflectApply(resource.runInAsyncScope, resource, args);
+      };
+    } else {
+      bound = FunctionPrototypeBind(this.runInAsyncScope, this, fn, thisArg);
+    }
+    ObjectDefineProperties(bound, {
       'length': {
         configurable: true,
         enumerable: false,
@@ -245,7 +250,7 @@ class AsyncResource {
         writable: true,
       }
     });
-    return ret;
+    return bound;
   }
 
   static bind(fn, type, thisArg) {

test/parallel/test-asyncresource-bind.js

@@ -41,7 +41,7 @@ const fn3 = asyncResource.bind(common.mustCall(function() {
 fn3();
 
 const fn4 = asyncResource.bind(common.mustCall(function() {
-  assert.strictEqual(this, asyncResource);
+  assert.strictEqual(this, undefined);
 }));
 fn4();
 
@@ -49,3 +49,8 @@ const fn5 = asyncResource.bind(common.mustCall(function() {
   assert.strictEqual(this, false);
 }), false);
 fn5();
+
+const fn6 = asyncResource.bind(common.mustCall(function() {
+  assert.strictEqual(this, 'test');
+}));
+fn6.call('test');