1195336 - setTimeout callback called before promise callback

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Jake Archibald]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.155 Safari/537.36

Steps to reproduce:

http://jsbin.com/yokugu/edit?js,console


Actual results:

`setTimeout` is logged before `promise1`.


Expected results:

Microtasks (promise callbacks) should execute before additional tasks (setTimeout).

Firefox 39 did the right thing, but 40 appears to have regressed.

Comment 1

[Ben Kelly [:bkelly, not reviewing]]

I tested this in nightly 43 and dev edition 42 and it does not reproduce any more.  It does seem to effect 40 and 41, though.

Comment 2

[Jake Archibald]

Ah, really sorry, I could have sworn I saw it failing in nightly, but I think I've been staring at these tests too long. Happy for this to close.

Comment 3

[Ben Kelly [:bkelly, not reviewing]]

Well, if we can find the bug that fixed this, maybe we could uplift it to beta 41 before the next merge.

Comment 4

[Jake Archibald]

I ran:

mozregression --find-fix --bad-release 40 --arg="https://jakearchibald.com/2015/tasks-microtasks-queues-and-schedules/"

…but it didn't give me a "bad" version. I guess I'm using it wrong, unless the bug somehow doesn't happen in nightlies, but hit the release.

Comment 5

[Nikhil Marathe [:nsm] (No longer reading bugmail, please needinfo?)]

Bug 1179909 fiddled with event loops and Promises, but that landed in Nightly 43 after 42 branched.

Comment 6

[Boris Zbarsky [:bzbarsky]]

> Well, if we can find the bug that fixed this

I was going to guess bug 1162013, but that landed in 40...

Also, I can't reproduce this in 40 or 41 or 39, though at least in 39 I can describe how it _could_ happen (see bug 1162013).

Comment 7

[Till Schneidereit [:till]]

The affected versions are long gone, closing.