Fixed resolving when Promise is inherited.

Previously, njs_promise_resolve() might return njs_object_t instead of
njs_promise_t. Later an instance of njs_object_t was put into a
NJS_PROMISE value. Whereas njs_promise_t is always expected to be inside
of a NJS_PROMISE value.

This closes #813 issue on Github.

src/njs_promise.c

@@ -675,27 +675,19 @@ static njs_int_t
 njs_promise_object_resolve(njs_vm_t *vm, njs_value_t *args, njs_uint_t nargs,
     njs_index_t unused, njs_value_t *retval)
 {
-    njs_promise_t  *promise;
-
     if (njs_slow_path(!njs_is_object(njs_argument(args, 0)))) {
         njs_type_error(vm, "this value is not an object");
         return NJS_ERROR;
     }
 
-    promise = njs_promise_resolve(vm, njs_argument(args, 0),
-                                  njs_arg(args, nargs, 1));
-    if (njs_slow_path(promise == NULL)) {
-        return NJS_ERROR;
-    }
-
-    njs_set_promise(retval, promise);
-
-    return NJS_OK;
+    return njs_promise_resolve(vm, njs_argument(args, 0),
+                               njs_arg(args, nargs, 1), retval);
 }
 
 
-njs_promise_t *
-njs_promise_resolve(njs_vm_t *vm, njs_value_t *constructor, njs_value_t *x)
+njs_int_t
+njs_promise_resolve(njs_vm_t *vm, njs_value_t *constructor, njs_value_t *x,
+    njs_value_t *retval)
 {
     njs_int_t                 ret;
     njs_value_t               value;
@@ -707,26 +699,28 @@ njs_promise_resolve(njs_vm_t *vm, njs_value_t *constructor, njs_value_t *x)
         ret = njs_value_property(vm, x, njs_value_arg(&string_constructor),
                                  &value);
         if (njs_slow_path(ret == NJS_ERROR)) {
-            return NULL;
+            return NJS_ERROR;
         }
 
         if (njs_values_same(&value, constructor)) {
-            return njs_promise(x);
+            njs_value_assign(retval, x);
+            return NJS_OK;
         }
     }
 
     capability = njs_promise_new_capability(vm, constructor);
     if (njs_slow_path(capability == NULL)) {
-        return NULL;
+        return NJS_ERROR;
     }
 
     ret = njs_function_call(vm, njs_function(&capability->resolve),
                             &njs_value_undefined, x, 1, &value);
     if (njs_slow_path(ret != NJS_OK)) {
-        return NULL;
+        return ret;
     }
 
-    return njs_promise(&capability->promise);
+    njs_value_assign(retval, &capability->promise);
+    return NJS_OK;
 }
 
 
@@ -1017,7 +1011,6 @@ njs_promise_then_finally_function(njs_vm_t *vm, njs_value_t *args,
 {
     njs_int_t              ret;
     njs_value_t            value, argument;
-    njs_promise_t          *promise;
     njs_function_t         *function;
     njs_native_frame_t     *frame;
     njs_promise_context_t  *context;
@@ -1031,13 +1024,11 @@ njs_promise_then_finally_function(njs_vm_t *vm, njs_value_t *args,
         return ret;
     }
 
-    promise = njs_promise_resolve(vm, &context->constructor, &value);
-    if (njs_slow_path(promise == NULL)) {
+    ret = njs_promise_resolve(vm, &context->constructor, &value, &value);
+    if (njs_slow_path(ret != NJS_OK)) {
         return NJS_ERROR;
     }
 
-    njs_set_promise(&value, promise);
-
     function = njs_promise_create_function(vm, sizeof(njs_value_t));
     if (njs_slow_path(function == NULL)) {
         return NJS_ERROR;

src/njs_promise.h

@@ -36,8 +36,8 @@ njs_function_t *njs_promise_create_function(njs_vm_t *vm, size_t context_size);
 njs_int_t njs_promise_perform_then(njs_vm_t *vm, njs_value_t *value,
     njs_value_t *fulfilled, njs_value_t *rejected,
     njs_promise_capability_t *capability, njs_value_t *retval);
-njs_promise_t *njs_promise_resolve(njs_vm_t *vm, njs_value_t *constructor,
-    njs_value_t *x);
+njs_int_t njs_promise_resolve(njs_vm_t *vm, njs_value_t *constructor,
+    njs_value_t *x, njs_value_t *retval);
 
 
 extern const njs_object_type_init_t  njs_promise_type_init;

src/njs_vmcode.c

@@ -2637,7 +2637,6 @@ njs_vmcode_await(njs_vm_t *vm, njs_vmcode_await_t *await,
     njs_int_t           ret;
     njs_frame_t         *frame;
     njs_value_t         ctor, val, on_fulfilled, on_rejected, *value, retval;
-    njs_promise_t       *promise;
     njs_function_t      *fulfilled, *rejected;
     njs_native_frame_t  *active;
 
@@ -2651,8 +2650,8 @@ njs_vmcode_await(njs_vm_t *vm, njs_vmcode_await_t *await,
 
     njs_set_function(&ctor, &njs_vm_ctor(vm, NJS_OBJ_TYPE_PROMISE));
 
-    promise = njs_promise_resolve(vm, &ctor, value);
-    if (njs_slow_path(promise == NULL)) {
+    ret = njs_promise_resolve(vm, &ctor, value, &val);
+    if (njs_slow_path(ret != NJS_OK)) {
         return NJS_ERROR;
     }
 
@@ -2710,7 +2709,6 @@ njs_vmcode_await(njs_vm_t *vm, njs_vmcode_await_t *await,
     rejected->args_count = 1;
     rejected->u.native = njs_await_rejected;
 
-    njs_set_promise(&val, promise);
     njs_set_function(&on_fulfilled, fulfilled);
     njs_set_function(&on_rejected, rejected);
 

test/js/promise_s27.t.js

@@ -0,0 +1,34 @@
+/*---
+includes: []
+flags: [async]
+---*/
+
+var inherits = (child, parent) => {
+    child.prototype = Object.create(parent.prototype, {
+        constructor: {
+        value: child,
+        enumerable: false,
+        writable: true,
+        configurable: true
+        }
+    });
+    Object.setPrototypeOf(child, parent);
+};
+
+function BoxedPromise(executor) {
+    var context, args;
+    new Promise(wrappedExecutor);
+    executor.apply(context, args);
+
+    function wrappedExecutor(resolve, reject) {
+        context = this;
+        args = [v => resolve(v),v => reject(v)];
+    }
+}
+
+inherits(BoxedPromise, Promise);
+
+Promise.resolve()
+.then(() => BoxedPromise.resolve())
+.catch(e => assert.sameValue(e.constructor, TypeError))
+.then($DONE, $DONE);