1045616 - Starting the inspector for the Camera app freezes Firefox

Status: VERIFIED FIXED

(DevTools Graveyard :: WebIDE, defect)

Description

[Paul Rouget [:paul]]

Debugging the camera app, starting the toolbox (inspector being the default tool) freezes Firefox. At least on mac and linux.

Comment 1

[Paul Rouget [:paul]]

This happens only with the inspector, and it happens both with the simulator and the device.

Comment 2

[Paul Rouget [:paul]]

Not a problem with Aurora.

Comment 3

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

I can reproduce this issue.  It seems to only affect 2.1, as 2.0 and 1.4 simulators did not show the problem.

Comment 4

[Paul Rouget [:paul]]

bug 1040697 is the problem.

Comment 5

[Paul Rouget [:paul]]

Mike, I need some help here.
bug 1040697 introduced a for loop:

> for (let prop of subProps)

In the case of the camera app, at some point, subProps has more than 6000 keys, and going though all the keys take a lot of time. And Firefox freeze.

Comment 6

[Paul Rouget [:paul]]

I'm not sure exactly what's going on. I added:

> console.log("PAUL " + Object.keys(subProps).length);

And I see "6398" being printed around 50 times. Then Firefox freezes, and eventually I see:

> 2014-07-30 16:13:20: stackwalker.cc:125: INFO: Couldn't load symbols for: /home/paul/mozilla/src/obj.firefox/dist/bin/libxul.so|

And after some time, Firefox unfreezes.

Comment 7

[Paul Rouget [:paul]]

If I add a `return` right before the `try`, it doesn't freeze anymore.

Comment 8

[Mike Ratcliffe [:miker] [:mratcliffe] [:mikeratcliffe]]

Regression due to bug 1040697

Comment 9

[Paul Rouget [:paul]]

Ok - this is an issue with variable:

> console.log("PAUL " + this.name + " > " + Object.keys(subProps).length);


console.log: PAUL --color-brand-darkblue > 6398
console.log: PAUL --color-brand-blue > 6398
console.log: PAUL --color-brand-turquoise > 6398
console.log: PAUL --color-brand-darkorange > 6398
console.log: PAUL --color-brand-orange > 6398
console.log: PAUL --color-brand-yellow > 6398
console.log: PAUL --color-brand-violet > 6398
console.log: PAUL --color-brand-alpha > 6398
console.log: PAUL --color-brand-beta > 6398
console.log: PAUL --color-brand-gamma > 6398
console.log: PAUL --dim-micro > 6398
console.log: PAUL --dim-milli > 6398
console.log: PAUL --dim-small > 6398
console.log: PAUL --dim-medium > 6398
console.log: PAUL --dim-large > 6398
console.log: PAUL --dim-mega > 6398
console.log: PAUL --font-small > 6398
console.log: PAUL --font-medium > 6398
console.log: PAUL --font-large > 6398
console.log: PAUL --header-background > 6398
console.log: PAUL --header-nav-button-color > 6398
console.log: PAUL --header-nav-button-color-active > 6398
console.log: PAUL --header-button-background > 6398
console.log: PAUL --header-button-color-active > 6398
console.log: PAUL --header-button-color > 6398
console.log: PAUL --header-title-color > 6398
console.log: PAUL --button-background > 6398
console.log: PAUL --button-background-active > 6398
console.log: PAUL --button-color > 6398
console.log: PAUL --button-color-active > 6398
console.log: PAUL --button-transition > 6398

Comment 10

[Brian Grinstead [:bgrins]]

If it is truly a performance issue with the loop, try switching it to a traditional for loop.  `for of` isn't optimized and is significantly slower.

Comment 11

[Paul Rouget [:paul]]

Nope. The issue is:

Cc["@mozilla.org/inspector/dom-utils;1"].getService(Ci.inIDOMUtils).getSubpropertiesForCSSProperty("--foo")

This return a super huge array. It makes no sense. Platform issue.

Comment 12

[Paul Rouget [:paul]]

Found a fix. See bug 1046140.

Comment 13

[Paul Rouget [:paul]]

It works now. See bug 1046140.

Comment 14

[Petruta Horea [:phorea], Desktop QA]

Reproduced using Nightly 2014-07-29 with 2.1 and 2.2 simulators - freeze on Ubuntu 12.04 64-bit and Mac OSX 10.9.5 and crash under Win 7 64-bit.
The issue no longer occurs using latest Aurora 34.0a2 2014-10-09 and the simulators under all platforms.