Cassidy’s Blog

Use Commit from Flatpak Both Inside and Outside of Toolbx

Is this terrible? Probably. But it works!

This one’s gonna be a short one, and is mostly for my own notes. :)

I like to use the Commit app as a visual editor when committing changes to a git repo; it’s a simple dialog that gives some niceties over using the CLI, like spell check, a visual indication of line length, graying out comments, etc. It’s nice!

Here are the instructions provided by Commit to edit your git config:

git config --global core.editor "flatpak run re.sonny.Commit"

Since I’m often in a toolbx container when developing, I can’t directly access my host’s Flatpaks (which makes sense!), and thus the provided instructions don’t work in this context.

Update: Just Install Flatpak in the Toolbx Container!

Thanks to Felipe and Sebastian in the comments, I learned Flatpak inside a toolbx container is actually smart, and will launch host Flatpaks on the host! So all you actually need to do is:

sudo dnf install flatpak

…or your toolbx container distro’s equivalent, then the instructions provided by Commit should Just Work™️.

If you get an error about unpacking rpm package flatpak, you may be on an older version of toolbx and need to work around a bug; just sudo umount /var/lib/flatpak, then install Flatpak, then restart your container exit it, then podman stop fedora-toolbox-39 (or your container name), then toolbox enter fedora-toolbox-39 (or your container name) again.

Edit the Git Config (Outdated!)

I could modify my git config to work in the container by using flatpak-spawn (which, despite its name, you can use to spawn things outside of toolbx containers as well as outside of flatpaks), but then it won’t work on the host, which I also need! So I have to dynamically handle both cases…

After a bit of trial and error, I came up with this kludge:

git config --global core.editor 'if [ -f /run/.toolboxenv ]; then prefix="flatpak-spawn --host"; fi && $prefix flatpak run re.sonny.Commit'

If all you wanted was for this to work for you, copy the above and you’re done. :)

How it works

Let’s step through it to better understand what’s going on. I’m going to break it into lines to make it easier to read; I know this can’t be parsed as-is by bash, but just bear with the visual:

git config --global core.editor '
  if [ -f /run/.toolboxenv ]; then 
    prefix="
      flatpak-spawn --host
    ";
  fi 
  && 
  $prefix flatpak run re.sonny.Commit
'

So the outer-most part is that we’re setting the core.editor variable globally with git config, just as Commit’s original instructions say. We’re using single-quotes (') here because we don’t want our $prefix to be interpreted as string replacement at the time we set the variable, which double-quotes (") would do; we just want to include that in the literal string (to be replaced when git runs it).

Next we have an if to check if the file /run/.toolboxenv exists; this exists in all toolbx containers, so it’s an easy way to know if we’re running in toolbx.

If we’re in toolbx, we set a new variable prefix to flatpak-spawn --host since we need to run the actual editor on the host, not in our container. We use double-quotes (") here since we’re inside of the single-quoted (') string.

After we successfully do the toolbx check and optionally set the prefix, && will tell the shell that’s calling the commit program to execute the next bit.

We include the actual original flatpak run re.sonny.Commit, this time prefixed by $prefix, which will either be string-replaced by a harmless empty string, or by our flatpak-spawn --host if we’re in a toolbx container.

We have to leave the command for the end of our kludged string because git will append the temporary filename of the commit message to the end of the whole core.editor string; if we included flatpak-span --host flatpak run re.sonny.Commit inside the if statement, it would never get the name of the file to edit, and wouldn’t work (ask me how I know…).

So there we are. It’s super ugly, but hey, it works. How would you solve this in a better way? Let me know on social media. :)