715474 - Successive zombie compartments with add-on "Screengrab (fix version)" 0.96.3c

Status: RESOLVED FIXED

(Firefox :: Untriaged, defect)

Description

[Loic]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0a1) Gecko/20120104 Firefox/12.0a1
Build ID: 20120104031035

Steps to reproduce:

It's a bug report just for the record because the relevant add-on is reported as EOL by its author and reported as incompatible with FF9+ (but major functions work).

The leaky add-on is Screengrab 0.96.3 (see https://addons.mozilla.org/en-US/firefox/addon/1146 ) that allows you to take a snapshot (selection, visible portion, complete page, window) of the webpage you're visiting.

STR:
1) Create a new profile and enable the add-on bar
2) Install Screengrab 0.96.3 from https://addons.mozilla.org/en-US/firefox/addon/screengrab/ (Add-on Compatibility Reporter is eventually necessary to force the compatibility of Screengrab in FF9+)
3) Open about:memory?verbose
4) Open http://my.yahoo.com/ (heavy JS website) in another tab
5) Click on Screengrab icon, select "Save > Visible portion..." and save the snapshot as PNG image
6) Close the tab http://my.yahoo.com/
7) Return to about:memory?verbose, hit the "minimize memory usage" button few times and wait for 5 min to observe the zombie compartment:

│  ├───6,643,432 B (14.68%) -- compartment(http://my.yahoo.com/)
│  │   ├──4,358,144 B (09.63%) -- gc-heap
│  │   │  ├──2,028,304 B (04.48%) -- arena
│  │   │  │  ├──2,001,488 B (04.42%) -- unused
│  │   │  │  ├─────17,024 B (00.04%) -- headers
│  │   │  │  └──────9,792 B (00.02%) -- padding
│  │   │  ├──1,039,136 B (02.30%) -- objects
│  │   │  │  ├────707,328 B (01.56%) -- non-function
│  │   │  │  └────331,808 B (00.73%) -- function
│  │   │  ├────551,920 B (01.22%) -- shapes
│  │   │  │    ├──269,352 B (00.60%) -- dict
│  │   │  │    ├──227,496 B (00.50%) -- tree
│  │   │  │    └───55,072 B (00.12%) -- base
│  │   │  ├────360,496 B (00.80%) -- strings
│  │   │  ├────287,856 B (00.64%) -- scripts
│  │   │  └─────90,432 B (00.20%) -- type-objects
│  │   ├────533,728 B (01.18%) -- script-data
│  │   ├────528,032 B (01.17%) -- shapes-extra
│  │   │    ├──361,472 B (00.80%) -- tree-tables
│  │   │    ├───98,272 B (00.22%) -- dict-tables
│  │   │    ├───47,680 B (00.11%) -- tree-shape-kids
│  │   │    └───20,608 B (00.05%) -- compartment-tables
│  │   ├────457,504 B (01.01%) -- object-slots
│  │   ├────327,680 B (00.72%) -- mjit-code
│  │   ├────157,496 B (00.35%) -- type-inference
│  │   │    ├──121,296 B (00.27%) -- object-main
│  │   │    └───36,200 B (00.08%) -- tables
│  │   ├────141,312 B (00.31%) -- analysis-temporary
│  │   └────139,536 B (00.31%) -- string-chars

8) Open https://bugzilla.mozilla.org/ (low JS website) in another tab
9) Click on Screengrab icon, select "Save > Visible portion..." and save the snapshot as PNG image
10) Close the tab https://bugzilla.mozilla.org/
11) Return to about:memory?verbose, hit the "minimize memory usage" button few times and wait for 5 min to observe the new zombie compartment succeeding to the previous one:

│  ├─────222,256 B (00.50%) -- compartment(https://bugzilla.mozilla.org/)
│  │     ├──143,360 B (00.33%) -- gc-heap
│  │     │  ├──125,272 B (00.28%) -- arena
│  │     │  │  ├──124,344 B (00.28%) -- unused
│  │     │  │  ├──────560 B (00.00%) -- headers
│  │     │  │  └──────368 B (00.00%) -- padding
│  │     │  ├───10,712 B (00.02%) -- shapes
│  │     │  │   ├───3,816 B (00.01%) -- dict
│  │     │  │   ├───3,680 B (00.01%) -- base
│  │     │  │   └───3,216 B (00.01%) -- tree
│  │     │  ├────6,032 B (00.01%) -- objects
│  │     │  │    ├──5,024 B (00.01%) -- function
│  │     │  │    └──1,008 B (00.00%) -- non-function
│  │     │  ├──────768 B (00.00%) -- type-objects
│  │     │  └──────576 B (00.00%) -- scripts
│  │     ├───65,536 B (00.15%) -- mjit-code
│  │     ├────6,784 B (00.02%) -- shapes-extra
│  │     │    ├──4,416 B (00.01%) -- compartment-tables
│  │     │    ├──2,016 B (00.00%) -- dict-tables
│  │     │    ├────256 B (00.00%) -- tree-shape-kids
│  │     │    └─────96 B (00.00%) -- tree-tables
│  │     ├────5,120 B (00.01%) -- object-slots
│  │     ├────1,344 B (00.00%) -- type-inference
│  │     │    └──1,344 B (00.00%) -- tables
│  │     └──────112 B (00.00%) -- script-data


Actual results:

Each time you take a snapshot, Screengrab 0.96.3 releases the memory of the previous zombie compartment and a new zombie compartment is created. Especially when the website is heavy in JS, the zombie compartment may be large.

Comment 1

[Dão Gottwald [:dao]]

Note that Screengrab doesn't officially support Firefox 4 and later.

Comment 2

[Justin Lebar (not reading bugmail)]

> It's a bug report just for the record because the relevant add-on is reported as EOL by its author 
> and reported as incompatible with FF9+ (but major functions work).

If the author no longer supports the add-on, then this is wontfix, right?

Comment 3

[Loic]

I emailed the author Andy Mutton, let's see if he will reply in 1 week or 2. Then close it as wontfix, I think.

Comment 4

[Justin Lebar (not reading bugmail)]

sgtm!

Comment 5

[Loic]

18 days after my email to author Andy Mutton, no reply. So I think you can close this bug as wontfix.

Comment 6

[Justin Lebar (not reading bugmail)]

Jorge, is this a candidate for a nag screen on AMO?

Comment 7

[Dão Gottwald [:dao]]

(In reply to Justin Lebar [:jlebar] from comment #6)
> Jorge, is this a candidate for a nag screen on AMO?

The addon isn't compatible with recent versions of Firefox. Nobody has investigated whether this bug exists with Firefox 3.6, as far as I can tell.

Comment 8

[Justin Lebar (not reading bugmail)]

> reported as incompatible with FF9+ (but major functions work).

Indeed; I forgot about this.  If it's incompatible then I don't care.

Comment 9

[Jorge Villalobos [:jorgev] (he/him)]

I just added Screengrab to the compatibility override list, so that Firefox 10 and above will flag it as incompatible.

Comment 10

[Dão Gottwald [:dao]]

Add-ons that are incompatible with Firefox 4 won't be considered compatible anyway.

Comment 11

[Jorge Villalobos [:jorgev] (he/him)]

It is marked as compatible with 6.* on AMO.

Comment 12

[Dão Gottwald [:dao]]

Huh, I thought I saw a max version of 3.6 when I checked this a few weeks ago. I either misread this, or Andy (CC'd to this bug, btw) is actually still active and updated the version range.

Comment 13

[Andy Mutton]

It doesn't work consistently on all platforms with any versions past 5 I think. 
Things changed and I don't have the time or inclination to keep messing with it to make it work.
If I ever start thinking about working on this again I'll look at this bug, but that is extremely unlikely.

There is, however, a version that someone is bumping the compatibility numbers on...
https://addons.mozilla.org/en-US/firefox/addon/screengrab-fix-version/

Whoever they are, they might care.

Comment 14

[Nicholas Nethercote [inactive]]

Let's reopen this for the "(fix version)" version.

I tried to find the new author's email but failed.

Comment 15

[Loic]

I think it's a trivial fork they did, only to bump the maxversion, not really a full maintenance of the previous add-on.

Comment 16

[Jorge Villalobos [:jorgev] (he/him)]

I sent a message to the developer of the fork.

Comment 17

[Leszek Zyczkowski]

I tested new 0.96.4c version and not observe zombie compartment.

Comment 18

[Loic]

Is the 0.96.4c version available on AMO?

Comment 19

[Jorge Villalobos [:jorgev] (he/him)]

I don't see it anywhere. Teo, where did you find this version?

Comment 20

[Leszek Zyczkowski]

(In reply to Jorge Villalobos [:jorgev] from comment #19)
> I don't see it anywhere. Teo, where did you find this version?

This version is here:
https://addons.mozilla.org/en-US/firefox/addon/screengrab-fix-version/versions/

Comment 21

[Jorge Villalobos [:jorgev] (he/him)]

Right. I forgot this was about the fork and not the original.

Comment 22

[Jorge Villalobos [:jorgev] (he/him)]

This is fixed in the "fix version" now, and the old version is marked incompatible in Firefox 10 and above.