1368170 - Remove unused Function.prototype.inherits methods

Status: RESOLVED FIXED

(Toolkit :: Safe Browsing, enhancement)

Description

[Andrew McCreight [:mccr8]]

content/moz/lang.js and nsUrlClassifierListManager.js both define a method named "inherits" on Function.prototype, which I guess is supposed to be some kind of class-based inheritance. However, as far as I can tell, these methods are never called. There are a few places that explicitly call a .inherits methods, but they define them right before their use, so hopefully this is okay.

I want to make this change because with JSM global sharing (bug 1186409) changing Function.prototype in this way affects all JSMs, including Services.jsm. Marionette code tries to serialize Services.appInfo, which has a field QueryInterface, which is a function. Because of the inherits field on Function.prototype, this serialization seems to result in infinite recursion. (Presumably because the inherits method is itself a function.)

Comment 1

[Andreas Tolfsen ❲:ato❳]

(In reply to Andrew McCreight [:mccr8] from comment #0)
> Marionette code tries to serialize Services.appInfo, which has
> a field QueryInterface, which is a function. Because of the inherits field
> on Function.prototype, this serialization seems to result in infinite
> recursion. (Presumably because the inherits method is itself a function.)

This seems like a bug.  Do you have a link to the exact location where we try to serialise Services.appInfo directly?  I Know we extract values from it, but we should not be trying to serialise Services.appInfo.

Comment 2

[Andrew McCreight [:mccr8]]

(In reply to Andreas Tolfsen ‹:ato› from comment #1)
> This seems like a bug.  Do you have a link to the exact location where we
> try to serialise Services.appInfo directly?  I Know we extract values from
> it, but we should not be trying to serialise Services.appInfo.

I don't exactly know where it was happening, but the script it was running was the same as the one here, which is returning Services.appinfo:
http://searchfox.org/mozilla-central/source/testing/marionette/harness/marionette_harness/runner/base.py#669

Comment 3

[Andrew McCreight [:mccr8]]

It looks like this test also returns it:
http://searchfox.org/mozilla-central/source/testing/marionette/harness/marionette_harness/tests/unit/test_capabilities.py#17

Comment 4

[Andrew McCreight [:mccr8]]

Attachment: Bug 1368170 - Remove unused Function.prototype.inherits methods.

These methods do not appear to be used.

When JSM global sharing is enabled, these methods contaminate the
global Function.prototype, which breaks Marionette object
serialization.

Review commit: https://reviewboard.mozilla.org/r/143514/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/143514/

Comment 5

[Andrew McCreight [:mccr8]]

try is green: https://treeherder.mozilla.org/#/jobs?repo=try&revision=b75560596a7f2af0dfb6550a369d6acade8f390d

Comment 6

[François Marier [:francois]]

Comment on attachment 8871978 [details]
Bug 1368170 - Remove unused Function.prototype.inherits methods.

https://reviewboard.mozilla.org/r/143514/#review147912

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0a56ccf2f145
Remove unused Function.prototype.inherits methods. r=francois

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/0a56ccf2f145