1593005 - Using Adblock Plus (installing/enabling) makes Firefox report discarded tabs as not discarded

Status: NEW

(WebExtensions :: General, defect, P3)

Description

[ariasuni]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0

Steps to reproduce:

1. Load a webpage in tab, and discard it with “Unload Tab from Context Menu”1
2. Check that our tab is discarded: the context menu entry of 1 is greyed out.
3. Install Adblock Plus
4. Check that the the context menu entry of 1 for our tab is not greyed out anymore. However, clicking on our tab loads it, proving that is was still discarded but reported by the WebExtensions API as not discarded.

Note that I also checked by hand with browser.tabs.query() and browser.tabs.get() so I’m sure it’s a bug of Firefox.

Actual results:

Firefox reports discarded tabs as not discarded.

Expected results:

Firefox continues to report discarded tabs as discarded.

Comment 1

[ariasuni]

Sorry, I forget to check if the link for the extension worked and forgot to put one for Adblock Plus. Links:

• Unload Tab from Context Menu
• Adblock Plus

Comment 2

[Alex Cornestean]

Hello,

I have managed to reproduce the issue based on the provided STR on the latest Nightly (72.0a1/20191103213857), Beta (71.0b6/20191031113544) and Release (70.0.1/20191030021342) under Windows 10 Pro 64-bit and MacOS Catalina 10.15.

Installing or enabling “Adblock Plus” will cause the previously greyed out “Unload Tab” option (due to the tab already being unloaded) to revert back to it’s active state.

Comment 3

[Shane Caraveo (:mixedpuppy)]

I verified that it is specific to something adblock is doing. ie. installing facebook container does not result in the same problem.

Discarded state depends on a linkedPanel existing (or not), so it seems that there is likely some internal api that is causing the panel to be recreated. I would think though that would also cause the browser to reload.

https://searchfox.org/mozilla-central/rev/d061ba55ac76f41129618d638f4ef674303ec103/browser/components/extensions/parent/ext-browser.js#781-783

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

The component has been changed since the backlog priority was decided, so we're resetting it.
For more information, please visit auto_nag documentation.

Comment 5

[ariasuni]

Bug still present in 73.0b11.

Comment 6

[ariasuni]

Why is this bug P3? An extension can break the WebExtensions API for other extensions.

Still present in 76.0b4.