950853 - Reflect.parse: support builder methods that are callable but not JSFunctions

Status: RESOLVED WORKSFORME

(Core :: JavaScript Engine, defect)

Description

[Jason Orendorff [:jorendorff]]

The following doesn't work in a Browser Scratchpad:

Components.utils.import("resource://gre/modules/reflect.jsm") ;
Reflect.parse("42", { builder: {
  program: function program() {
    return 24;
  }
}});

It gives the error "(function program() {
    return 24;
  }) is not a function".

This is because what is actually passed to Reflect.parse is a transparent wrapper around the builder object, triggering this code in NodeBuilder::init:

            if (!funv.isObject() || !funv.toObject().is<JSFunction>()) {
                js_ReportValueErrorFlags(cx, JSREPORT_ERROR, JSMSG_NOT_FUNCTION,
                                         JSDVG_SEARCH_STACK, funv, js::NullPtr(), nullptr, nullptr);
                return false;
            }

Transparent wrappers around JSFunctions are not JSFunctions.

Reported by Florent Fayolle.

Comment 1

[Jason Orendorff [:jorendorff]]

Here is a workaround for Florent:

Components.classes["@mozilla.org/jsreflect;1"].createInstance()();
Reflect.parse("42", { builder: {
  program: function program() {
    return 24;
  }
}});

Comment 2

[Florent Fayolle]

Many thanks Jason for the workaround!

Florent