1327027 - For the first time the gif is shown, last part of the gif is repeated randomly

Status: NEW

(Core :: Graphics: ImageLib, defect, P3)

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509
STR_1:
0. Open page http://example.org/
1. Open devtools -> options, enable "disable HTTP cache". Don't close devtools
2. Open http://i.imgur.com/rAX0Suq.gif in that tab
3. Watch until the gif starts looping

AR:  For the first time, the last part of the gif (~0.8s) is repeated twice. See "screencast 1"
ER:  Browser shouldn't randomly repeat any parts of gif. It should loop in a normal way

Notes:
1) Reload the page to get the same effect again. Step 2 only required not to store gif in cache
2) I think the right component is image lib

Comment 1

[Timothy Nikkel (:tnikkel)]

(In reply to arni2033 [Please stop 'improving' Firefox] from comment #0)
> >>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509

Are you really using a 7 month old nightly? Please update! The animated gif code has specifically had fixes in 2016 that could be very applicable to this situation.

> STR_1:
> 0. Open page http://example.org/
> 1. Open devtools -> options, enable "disable HTTP cache". Don't close
> devtools
> 2. Open http://i.imgur.com/rAX0Suq.gif in that tab
> 3. Watch until the gif starts looping
> 
> AR:  For the first time, the last part of the gif (~0.8s) is repeated twice.

Couldn't reproduce this in Aurora (2016-12-26).

> See "screencast 1"

No screencast attached or linked that I can see.

Comment 2

[arni2033]

Attachment: screencast 1 - gif strangely renders.webm

Comment 3

[Timothy Nikkel (:tnikkel)]

Is that in a current nightly? I pretty sure I've specifically fixed a bug in the animated gif code that would cause exactly that effect.

Comment 4

[arni2033]

> Are you really using a 7 month old nightly? Please update! The animated gif code has specifically
> had fixes in 2016 that could be very applicable to this situation.
Huh... I was not using 7 month old nightly at the moment I wrote this report (~2016-08-10).
I won't update until I document all noticeable bugs on Nightly 2016-05-26 that are also present on
latest versions. Yes, some of the bugs I reported today may already be fixed, but most of them aren't

> Is that in a current nightly? I pretty sure I've specifically fixed a bug in
> the animated gif code that would cause exactly that effect.
> 
> Couldn't reproduce this in Aurora (2016-12-26).
The video is recorded with reported version(!). Doing otherwise is just bad.
I don't need to explain that your testing doesn't exclude false-positive results, but if you're so sure, mark this as "worksforme", but not "verified". (I'm pressed on time a bit, so I won't test it).

Comment 5

[Timothy Nikkel (:tnikkel)]

I tried the 2016-05-26 nightly and I was able to reproduce. Since the bug appears to be fixed for me I bisected to determine what fixed this and I got

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=2f8e2b313b7aee4466c2e71e034ac203807f330e&tochange=70369395b75433f29f313b7426681c2bd7ec4bc1

Which makes a lot of sense.

If you get some more time I'd appreciate if you could re-test.