I did blog this before, but I have this time around had a successful instance of using this, because in this instance the application concerned did have sufficient commits available to roll back a point release. This example is the beta edition of Gimp, which I have been testing on a computer for some months.
First thing is to find out what commits are available to roll back to. We do this with the command
flatpak remote-info –log flathub org.gimp.GIMP
This command form would be correct for the production version of Gimp. However since we are using the beta edition, the command is modified slightly to
flatpak remote-info –log flathub-beta org.gimp.GIMP
The results from running that include this entry:
Subject: Release GIMP 2.99.8. (908bf5b0)
Date: 2021-10-20 20:29:00 +0000
In this instance, we are rolling back Gimp Beta from 2.99.10 to 2.99.8. To achieve this, we give the following Flatpak command:
flatpak update –commit=3c5198b67b1163900c0b43a248495f10864300894da1047b org.gimp.GIMP (all on one line).
This works because the Gimp project has maintained sufficient commits in the repository to permit rollbacks. In real life, quite often applications don’t have many previous commits to roll back to, and so a rollback can’t be performed.
UPDATE 2022-06-01: The flatpak command above has some issues, and the following is correct. Note in particular the need for //beta on the end, especially if you have multiple flatpak versions of Gimp installed.
flatpak update –commit=3c5198b67b1163900c0b43a248495f10864300894da1047b68dc7a87ebf0fbd5 org.gimp.GIMP//beta
Also important to note, which has not always been rendered properly in some typefaces is the double dashes (e.g. –) which are needed for some parameters (Linux command parameters are usually either single dash or double dash, with the single dash prefixing a short form option such as a single letter, and the double dash prefixing a long form option such as a full command word). So in the above command, it is a double dash, even though you can’t see that, and the same in the command that lists the available updates, with the log parameter. When you paste the above command, you need to use the back arrow key to get back in the command line entry to delete the single dash and replace it with two dashes, so that the command is correctly entered.
The reason for rolling back is significant new issues existed in 2.99.10 edition of the Gimp beta, and it is essentially unusable for many people until the next beta hopefully addresses these issues.