Reverting Flatpaks

Today, I learned a lot about Flatpak, motivated by Thunderbird giving me an error at startup.  The error message said that I had used the profile with “a newer version of Thunderbird,” and now it was not compatible.  It gave me the choice of creating a new profile, or quitting.  This was incredibly confusing, since I simply ran flatpak update as usual this morning, and took whatever was there.

That turned out to have been 115.13.0.  By the end of the day, it was “resolved” in the sense that a new version was published on Flathub (128.0esr) and that version was capable of opening my profile.

In the meantime, I learned more commands:

flatpak history

flatpak history produces a list of install/update activity, but it does not have version information at all. We can at least get the commit by asking for it specifically:

flatpak history --columns time,change,app,commit

Or with a sufficiently large terminal window (1920+ pixels wide), try using --columns all.

flatpak remote-info --log

It turns out that the remote can—and Flathub in particular does—keep older versions around for “a while.”  We can get these older versions, with their full commit IDs, by using flatpak remote-info with the repository and the package name.

flatpak remote-info --log flathub \
    org.mozilla.Thunderbird | less

(Line wrapped for readability on mobile; remove the backslash and put it all on one line.)

This prints out some nice header information, then the commit, followed by History.  For Thunderbird in particular, as I write this, the top 3 are:

• Commit: 2131b9d618… on 2024-07-17 16:26:34 +0000
• Commit: c2e09fc595… on 2024-07-16 18:58:52 +0000 (this is the one I installed this morning, about 2024-07-17 13:00:00 +0000.)
• Commit: 2151b1e101… on 2024-07-11 18:18:41 +0000 (which I installed 2024-07-12)

I opened a second terminal window, so I could copy and paste the full commit IDs between them, while experimenting.

sudo flatpak update --commit

Now that we have our old version, how do we install it?  Let’s assume the most-recent version wasn’t published yet, and I just wanted to roll back to my version from 2024-07-12.  We’ll pass its hash to the update command, and run it with root privileges:

sudo flatpak update --commit=2151b1e101… \
    org.mozilla.Thunderbird

Of course I did it without sudo at first, but after confirming, it failed, stating I needed root privileges.  I guess it makes sense (they don’t want someone who doesn’t know my password to downgrade to a known-vulnerable app and then exploit it) but I’m also miffed that it couldn’t tell me this before confirmation.

Anyway, one quick test later, I had my email again.

Versions in Flatpak

After the rollback, I checked the Thunderbird version through Help → About: it was “128.0esr, Mozilla Flatpak version 1.0”.

I followed up with a plain flatpak update org.mozilla.Thunderbird to get the latest 128.0esr build, and verified that was able to access my email as well.  I checked the version again in Help → About: it was “128.0esr, Mozilla Flatpak version 1.0”.

That’s why flatpak update and flatpak history don’t have version numbers at all.  They don’t have any guarantees of clarity or accuracy.

What I didn’t learn

I might have been able to give the short commit ID (from flatpak history) directly to flatpak update without going through flatpak remote-info --log in between.  I didn’t actually try it.

I kept trying to find information about branches, to see if there was a Thunderbird beta branch I could try since stable was broken, but I never did find any information about that.  There’s some build-related documentation about how to specify the branch during build, but absolutely nothing about listing available branches.

I also didn’t find anything about this situation in web searches.  How did version 115.x get pushed after 128.x?  Why did it take 21 hours to get it fixed?  Where would I find out whether Mozilla even knew about the problem?  I discovered it around 15:00, and couldn’t tell if anyone else was having the issue!

There’s a “Subject” in the flatpak remote-info --log data for each commit, but it is invariably “Export org.mozilla.Thunderbird”, so that didn’t add any signal, either.