1903580 - browser.cache.disk.enable resets to true after Firefox update

Status: RESOLVED DUPLICATE of bug 1903615

(Toolkit :: Application Update, defect)

Description

[jonathan]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:127.0) Gecko/20100101 Firefox/127.0

Steps to reproduce:

I used to set browser.cache.disk.enable and browser.cache.disk_cache_ssl to false in about:config.

Actual results:

After upgrading Firefox to 127.0, both properties have been reverted to true.
I updated these two properties to false in about:config again.
After upgrading Firefox to 127.0.1, browser.cache.disk.enable has been reverted to true.

Expected results:

Firefox upgrades should keep browser.cache.disk.enable and browser.cache.disk_cache_ssl values.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Core::Networking: Cache' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Tried across an update of nightly, it didn't change.
Are you running any extensions that might modify the value? Note that no guarantees are made about direct modifications to about:config, only for things done via Preferences.

Comment 3

[jonathan]

I'm using µBlock Origin only. I can try to disable it and see what happens on next Firefox update.

Comment 4

[Kershaw Chang [:kershaw]]

I don't think this is a necko bug. Maybe related to Update?

Comment 6

[Nick Rishel [:nrishel]]

Confirmed in Windows Sandbox, update from Fx126->Fx127. Update shouldn't touch this code afaik. That said, I don't see any code that modifies this value in source at all, so I'm a bit perplexed.

STR
Install an older version of Firefox.
Flip browser.cache.disk.enable to false.
Update Firefox and restart.
Check the browser.cache.disk.enable value.

Comment 7

[BugBot [:suhaib / :marco]]

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

Comment 8

[Masatoshi Kimura [:emk]]

I guess the background task is the culprit.

Background task sets the default branch of browser.cache.disk.enable value to false.
https://searchfox.org/mozilla-central/rev/64ddb621a0d3905fc2e3df475517d4163d377b22/toolkit/components/backgroundtasks/defaults/backgroundtasks.js#16

Even if users set the browser.cache.disk.enable value to false, the user-set value will be lost because the default value (false here) is the same as user-set one.

Next time when Firefox launches normally, browser.cache.disk.enable value will be the default (that is, true).

Comment 9

[Nick Rishel [:nrishel]]

I noticed that too but ruled it out. Background tasks shouldn't touch user profiles; they only use temporary (ephemeral) or per-task (non-ephemeral) profiles.

Comment 10

[Masatoshi Kimura [:emk]]

Workaround:

user_pref("browser.cache.disk.enable", false);

I added this line to user.js.

Comment 11

[Masatoshi Kimura [:emk]]

I set test.backgroundtask_specific_pref.exitCode to 79 and run update. The pref disappeared. If I set the value to something other than 79, the pref survives the update.

So I believe Background tasks fiddle with user profiles somehow or backgroundtasks.js is erroeneously applied to regular Firefox launch on update.

Comment 12

[Masatoshi Kimura [:emk]]

Maybe dupe of bug 1903615.
https://bugzilla.mozilla.org/show_bug.cgi?id=1903615#c18

Comment 13

[Masatoshi Kimura [:emk]]

Confirmed that the problem no longer happens with 130.0b1 to 130.0b2 update.