603849 - JS Error stacktrace in nightlies differs from previous versions

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[David Chan [:dchan]]

Attachment: test case

The latest nightlies appear to be missing the top most stack frame when an exception is thrown.

STR
1. Open test.html, it will open an alert with the stack

Firefox 4.0b6 / 3.6.9 displays
Error("foo")@:0
@file:///Users/dchan/test.html:5

Firefox 4.0b8pre displays
@file:///Users/dchan/test.html:5

Comment 1

[Andreas Gal :gal]

This also bit Myk with iterators.

Comment 2

[Blake Kaplan (:mrbkap) (inactive)]

Aren't both of these bugs fallout from slow native removal? (That is, aren't they JS engine "bugs?").

Comment 3

[Andreas Gal :gal]

Ah, right. Good point!

Comment 4

[Luke Wagner [:luke]]

This change is indeed from slow-native removal: the error constructor no longer pushes a stack frame.  This change in behavior was discussed ahead of time and considered acceptable.  If there is a good reason, we could add a non-frame entry corresponding to the arguments of the error constructor.

Comment 5

[Myk Melez [:myk] [@mykmelez]]

(In reply to comment #1)
> This also bit Myk with iterators.

Note: per my recent m.d.t.js-engine post <http://groups.google.com/group/mozilla.dev.tech.js-engine/browse_thread/thread/c1d4b5bf54e47bb5#c193c2c1c4851e8b>, over in bug 597004 I implemented the workaround suggested by Donny Viszneki <http://groups.google.com/group/mozilla.dev.tech.js-engine/browse_thread/thread/c1d4b5bf54e47bb5#77fbe60381c652aa> for the custom iterators in the Jetpack SDK.

Comment 6

[Luke Wagner [:luke]]

Great