Firefox: Moving from the Debian package to the Flatpak app (long-term?)

Wed 03 April 2024

First, thanks to Samuel Henrique for giving notice of recent Firefox CVEs in Debian testing/unstable.

At the time I didn't want to upgrade my system (Debian Sid) due to the ongoing t64 transition transition, so I decided I could install the Firefox Flatpak app instead, and why not stick to it long-term?

This blog post details all the steps, if ever others want to go the same road.

Flatpak Installation

Disclaimer: this section is hardly anything more than a copy/paste of the official documentation, and with time it will get outdated, so you'd better follow the official doc.

First thing first, let's install Flatpak:

$ sudo apt update
$ sudo apt install flatpak

Then the next step is to add the Flathub remote repository, from where we'll get our Flatpak applications:

$ flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo

And that's all there is to it! Now come the optional steps.

For GNOME and KDE users, you might want to install a plugin for the software manager specific to your desktop, so that it can support and manage Flatpak apps:

$ which gnome-software  && sudo apt install gnome-software-plugin-flatpak
$ which plasma-discover && sudo apt install plasma-discover-backend-flatpak

And here's an additional check you can do, as it's something that did bite me in the past: missing xdg-portal-* packages, that are required for Flatpak applications to communicate with the desktop environment. Just to be sure, you can check the output of apt search '^xdg-desktop-portal' to see what's available, and compare with the output of dpkg -l | grep xdg-desktop-portal.

As you can see, if you're a GNOME or KDE user, there's a portal backend for you, and it should be installed. For reference, this is what I have on my GNOME desktop at the moment:

$ dpkg -l | grep xdg-desktop-portal | awk '{print $2}'
xdg-desktop-portal
xdg-desktop-portal-gnome
xdg-desktop-portal-gtk

Install the Firefox Flatpak app

This is trivial, but still, there's a question I've always asked myself: should I install applications system-wide (aka. flatpak --system, the default) or per-user (aka. flatpak --user)? Turns out, this questions is answered in the Flatpak documentation:

Flatpak commands are run system-wide by default. If you are installing applications for day-to-day usage, it is recommended to stick with this default behavior.

Armed with this new knowledge, let's install the Firefox app:

$ flatpak install flathub org.mozilla.firefox

And that's about it! We can give it a go already:

$ flatpak run org.mozilla.firefox

Data migration

At this point, running Firefox via Flatpak gives me an "empty" Firefox. That's not what I want, instead I want my usual Firefox, with a gazillion of tabs already opened, a few extensions, bookmarks and so on.

As it turns out, Mozilla provides a brief doc for data migration, and it's as simple as moving the Firefox data directory around!

To clarify, we'll be copying data:

from ~/.mozilla/ -- where the Firefox Debian package stores its data
into ~/.var/app/org.mozilla.firefox/.mozilla/ -- where the Firefox Flatpak app stores its data

Let's make sure that all Firefox instances are closed, then proceed:

# BEWARE! Below I'm erasing data!
$ rm -fr ~/.var/app/org.mozilla.firefox/.mozilla/firefox/
$ cp -a ~/.mozilla/firefox/ ~/.var/app/org.mozilla.firefox/.mozilla/

To avoid confusing myself, it's also a good idea to rename the old data directory:

$ mv ~/.mozilla/firefox ~/.mozilla/firefox.old.$(date --iso-8601=date)

At this point, flatpak run org.mozilla.firefox takes me to my "usual" everyday Firefox, with all its tabs opened, pinned, bookmarked, etc.

More integration?

After following all the steps above, I must say that I'm 99% happy. So far, everything works as before, I didn't hit any issue, and I don't even notice that Firefox is running via Flatpak, it's completely transparent.

So where's the 1% of unhappiness? The « Run a Command » dialog from GNOME, the one that shows up via the keyboard shortcut <Alt+F2>. This is how I start my GUI applications, and I usually run two Firefox instances in parallel (one for work, one for personal), using the firefox -p <profile> command.

Given that I ran apt purge firefox before (to avoid confusing myself with two installations of Firefox), now the right (and only) way to start Firefox from a command-line is to type flatpak run org.mozilla.firefox -p <profile>. Typing that every time is way too cumbersome, so I need something quicker.

Seems like the most straightforward is to create a wrapper script:

$ cat /usr/local/bin/firefox 
#!/bin/sh
exec flatpak run org.mozilla.firefox "$@"

And now I can just hit <Alt+F2> and type firefox -p <profile> to start Firefox with the profile I want, just as before. Neat!

Looking forward: system updates

I usually update my system manually every now and then, via the well-known pair of commands:

$ sudo apt update
$ sudo apt full-upgrade

The downside of introducing Flatpak, ie. introducing another package manager, is that I'll need to learn new commands to update the software that comes via this channel.

Fortunately, there's really not much to learn. From flatpak-update(1):

flatpak update [OPTION...] [REF...]

Updates applications and runtimes. [...] If no REF is given, everything is updated, as well as appstream info for all remotes.

Could it be that simple? Apparently yes, the Flatpak equivalent of the two apt commands above is just:

$ flatpak update

Going forward, my options are:

Teach myself to run flatpak update additionally to apt update, manually, everytime I update my system.
Go crazy: let something automatically update my Flatpak apps, in my back and without my consent.

I'm actually tempted to go for option 2 here, and I wonder if GNOME Software will do that for me, given that I installed gnome-software-plugin-flatpak, and that I checked « Software Updates -> Automatic » in the Settings.

However, I didn't find any documentation regarding what this setting really does, so I can't say if it will only download updates, or if it will also install it. I'd be happy if it automatically installs new version of Flatpak apps.