[Pkg-mozext-maintainers] Bug#971693: webext-ublock-origin-firefox not compatible with non-empty user.js file

[Pascal Dormeau]

On Mon, 5 Oct 2020 21:02:09 +0200
Markus Koschany <apo at debian.org> wrote:

> Hello,
Hello Markus,
Thanks for replying.

> I have searched for a solution for this kind of problem but the more I
> dig into it the more I come to the conclusion that this kind of
> behavior is intentional. If you normally install addons via Firefox'
> addon feature, Firefox will tell you to restart the browser when you
> make an upgrade. It is comparable to Debian upgrades, some of them
> may require a restart and it can't be avoided.
> 
> Regarding the user.js file: I have just created one in my profile
> directory with a single line to change a setting, but I couldn't
> reproduce this problem on Firefox 78.3 with uBo 1.30.0 in stable. My
> workaround would be: save all your uBo settings (if you have made any
> changes, better safe than sorry), shut down Firefox, then remove
> user.js. Then restart Firefox and try to enable/disable the addon
> again. Afterwards you can readd your custom user.js file.
If I do this with my current profile, it fails, even before
re-enabling the custom user.js file.

If I create a fresh new profile, uBo is active. Then I close the browser
and copy the preferences I need directly to the pref.js file at the
end (instead of user.js), and restart the browser:
- the preferences are accepted (checked in about:config),
- and uBo remains active.
But if after I create a user.js file with one only single preference,
even with a default one like browser.cache.disk.enable (set to true),
it fails. And surprisingly, it fails again after removing  the user.js
file.

It seems to be related to the user.js file whatever the preferences
inside. And is irreversible. It can be circumvented by adding all
custom preferences to the pref.js only (and saving the most
important one elsewhere) without creating a user.js file.

> 
> If you send me your user.js file I can try to reproduce the problem in
> unstable tomorrow.
Any preference triggers the problem and one is enough. You can test
this one for example (I gave another example above):
user_pref("browser.tabs.tabMinWidth", 80);
If you do this, consider to use a fresh new profile.

> 
> There is also an addon debug mode for Firefox. This one allows you to
> skip restarts and you can make modifications to Firefox and your addon
> which get instantly applied.
I will try that, but the most likely, I will stick to the normal addon
from the addon firefox feature.
Just one more remark: I met the same problem with
webext-keepassxc-browser since 81.0 firefox version.

Best regards
Pascal