Potential cache upgrade issue in 3.28 results in unable to install flatpakref due to remote already existing

[Andrew Hayzen]

What happened
1) Open your browser, navigate to flathub.org, find an app and click to install it
2) Open the resulting flatpakref in gnome-software.
3) Notice how the app info is correctly displayed
4) Try to click install, notice how now you get "cannot install source from https://dl.flathub.org/repo/: flatpak source flathub already exists"

Note that I have 3.27.92 installed first and then upgraded to 3.28. After removing all installed apps and remotes I have not been able to reproduce the issue. It has been suggested that it is an issue in cache cleanup between versions - probably within ~/.cache/gnome-software/flatpak/

Furthermore note the actual issue was likely fixed in 3.28, so this is upgrades from lower than 3.28 to 3.28 which will be affected by cache upgrade issues.

I have reported the bug upstream here https://gitlab.gnome.org/GNOME/gnome-software/issues/328

[Jeremy Bícha (jbicha)]

If you have time, could you try starting from Ubuntu 17.10, then upgrade to 18.04 and see if you can reproduce the issue? You're welcome to use a virtual machine to make testing easier.

[Andrew Hayzen (ahayzen)]

Sure, when I get a moment I'll firstly try to reproduce the issue with bionic by installing 3.27.92 and upgrading to 3.28 again. Then if I can confirm that the issue really does happen, I'll try an upgrade from artful (3.26.1). (I hope this was only an issue within the development branch and therefore not affect "real" users, but we'll see).

[Andrew Hayzen (ahayzen)]

I've not yet been able to reproduce this yet, but while investigating I've found that the cache folder for gnome-software (and therefore the gnome software flatpak plugin) has changed from 17.10 to 18.04 - so it might not be an issue for "real" users upgrading from 17.10?

Eg the flatpak plugin cache folder has changed in the following ways for me:
17.10 ~/.cache/gnome-software/3.26/flatpak
18.04 ~/.cache/gnome-software/flatpak

Although this does raise, why is the cache folder not ~/.cache/gnome-software/3.28 ? What will happen with 3.30 ?