1410642 - Async scripts from webextensions loaded on Facebook can't access global variables

Status: RESOLVED DUPLICATE of bug 1408996

(WebExtensions :: General, defect)

Description

[mrmr1993]

Attachment: ff_variable_optimised_out.zip

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:56.0) Gecko/20100101 Firefox/56.0
Build ID: 20171003101344

Steps to reproduce:

Load the attached extension, which loads 2 content scripts on any URL:

content_script1.js:
window.test = {"test": "test"};

content_script2:js
window.addEventListener("DOMContentLoaded", function() {
  try {
    console.log(test.test);
  }
  catch (e) {
    console.log("Access failed:", e);
  }
});


Open facebook.com, logged in. (The extension seems to work as expected on all other URLs).


Actual results:

The console logs "Access failed: ReferenceError: test is not defined".


Expected results:

The console should log "test".


This issue affects Vimium-ff[0], specifically as (part of) [1], and so the extension doesn't work on Facebook for our Firefox users.

[0]: https://addons.mozilla.org/en-US/firefox/addon/vimium-ff/
[1]: https://github.com/philc/vimium/issues/2675

Comment 1

[mrmr1993]

Some more failing URLs from another issue filed against Vimium[0]:

https://support.microsoft.com/en-us/help/12445/windows-keyboard-shortcuts
https://support.microsoft.com/en-us/help/13805/windows-keyboard-shortcuts-in-apps