1241429 - blank items shown in context menu when Mozilla Archive Format enabled in Firefox 44

Status: RESOLVED WONTFIX

(Firefox :: Extension Compatibility, defect)

Description

[marvinhk]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0
Build ID: 20160118143821

Steps to reproduce:

install Mozilla Archive Format 3.1.1 with Firefox 43
open browser and right click page after upgrade to Firefox 44 betas
disable Mozilla Archive Format and restart Firefox


Actual results:

context menu is normal with Firefox 43
context menu shows a few blank ghost items which has no functions in Firefox 44
context menu is normal with Firefox 44 and addon disabled


Expected results:

no blank items should be shown

Comment 1

[YF (Yang)]

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=0814f2d30eda6175980be9318b8ed4a7fccaf435&tochange=733d3f5c161975dcd8ed476a7c923dad42c117eb


// This declaration is required for SeaMonkey compatibility.
let { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
TypeError: redeclaration of non-configurable global property Cc mafCommandsOverlay.js:39:16


[Tracking Requested - why for this release]:
An unexpected results, the changesets should not take effect for Fx44. I did not find out the cause of the problem, but it happens.

Comment 2

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

Olivier, is this something you can help investigate? Thanks!

Comment 3

[Olivier Yiptong [:oyiptong]]

ok. I'll take a look

Comment 4

[Olivier Yiptong [:oyiptong]]

Ok, I took a look with mconley and found the culprit and a solution. I actually set up a machine, but the solution lied in comment 1.

The error because of the assigned with let of Cc, Ci, Cu and Cr.

http://mxr.mozilla.org/mozilla-release/source/browser/base/content/browser.js?rev=c6b267589d0d#6

In the 44 version of browser.js, those variable names are assigned with the var keyword, as per bug 1202902.

Since those variables are already defined using var, the addon author could either:

1. wrap the variable declaration/assignments in a try/catch clause
2. use var instead of let on line 39 of mafCommandsOverlay.js

Comment 5

[Olivier Yiptong [:oyiptong]]

Looks like this hasn't been caught in bug 1213160. Will resolve WONTFIX here, since this was an intentional change, with mitigation strategies and instead add a comment on bug 1213160.

Comment 6

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

This is a wontfix with two possible workarounds mentioned in comment 4.