[Cinnamon] Software Manager won't launch if Flatpak is removed

[spamegg1]

Describe the bug
If Flatpak is removed, and the system receives some updates through Update Manager, Software Manager does not launch.

To Reproduce
Steps to reproduce the behavior:

1. Remove Flatpak with apt remove flatpak.
2. Receive some updates from the Update Manager.
3. Launch Software Manager with mintinstall.
4. See error:

 ➜ mintinstall
MintInstall: Detected system architecture: 'x86_64'
Traceback (most recent call last):
  File "/usr/lib/linuxmint/mintinstall/mintinstall.py", line 635, in do_activate
    if self.installer.init_sync():
  File "/usr/lib/python3/dist-packages/mintcommon/installer/installer.py", line 154, in init_sync
    if self._fp_remotes_have_changed():
  File "/usr/lib/python3/dist-packages/mintcommon/installer/installer.py", line 229, in _fp_remotes_have_changed
    fp_remotes = self.list_flatpak_remotes()
  File "/usr/lib/python3/dist-packages/mintcommon/installer/installer.py", line 346, in list_flatpak_remotes
    return _flatpak.list_remotes()
  File "/usr/lib/python3/dist-packages/mintcommon/installer/_flatpak.py", line 810, in list_remotes
    fp_sys = get_fp_sys()
  File "/usr/lib/python3/dist-packages/mintcommon/installer/_flatpak.py", line 68, in get_fp_sys
    _fp_sys = Flatpak.Installation.new_system(None)
gi.repository.GLib.GError: g-io-error-quark: While opening repository /var/lib/flatpak/repo: opening repo: opendir(/var/lib/flatpak/repo): No such file or directory (1)
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 153, in apport_excepthook
    with os.fdopen(os.open(pr_filename,
FileNotFoundError: [Errno 2] No such file or directory: '/var/crash/_usr_lib_linuxmint_mintinstall_mintinstall.py.1000.crash'

Original exception was:
Traceback (most recent call last):
  File "/usr/lib/linuxmint/mintinstall/mintinstall.py", line 635, in do_activate
    if self.installer.init_sync():
  File "/usr/lib/python3/dist-packages/mintcommon/installer/installer.py", line 154, in init_sync
    if self._fp_remotes_have_changed():
  File "/usr/lib/python3/dist-packages/mintcommon/installer/installer.py", line 229, in _fp_remotes_have_changed
    fp_remotes = self.list_flatpak_remotes()
  File "/usr/lib/python3/dist-packages/mintcommon/installer/installer.py", line 346, in list_flatpak_remotes
    return _flatpak.list_remotes()
  File "/usr/lib/python3/dist-packages/mintcommon/installer/_flatpak.py", line 810, in list_remotes
    fp_sys = get_fp_sys()
  File "/usr/lib/python3/dist-packages/mintcommon/installer/_flatpak.py", line 68, in get_fp_sys
    _fp_sys = Flatpak.Installation.new_system(None)
gi.repository.GLib.GError: g-io-error-quark: While opening repository /var/lib/flatpak/repo: opening repo: opendir(/var/lib/flatpak/repo): No such file or directory (1)

Expected behavior
Software Manager should launch in all cases.

Hardware and mintUpdate

• Is your system all up-to-date ? YES.

Additional context
Here is the problem again:

1. Remove flatpak apt remove flatpak
2. Receive updates from Update Manager
3. Software Manager mintinstall fails to launch
   The following fixes the problem:
4. Now reinstall Flatpak apt install flatpak
5. Now Software Manager launches OK.
6. Now Flatpak can be removed again with apt remove flatpak.
7. Software Manager still launches OK.
8. When the next update is received from Update Manager, the issue comes back. It happened in this cycle 4-5 times so far. Every time, installing/removing Flatpak fixes the issue.

[Harry-W-Haines-III]

Confirming the failure is repeatable.

[mtwebster]

I can't reproduce this.

Receive updates from Update Manager

What does that mean?

Did you install some updates? Or did you just refresh and there are new updates available?

Was this done on a clean install immediately after installation? Or did you run mintinstall, then remove it, then try to run again?

What if you remove gir1.2-flatpak-1.0 along with flatpak?

[spamegg1]

Receive updates from Update Manager
What does that mean?

Sorry, I meant I installed some available updates.

Was this done on a clean install immediately after installation? Or did you run mintinstall, then remove it, then try to run again?

Yes, after a clean install of Mint 21 Beta I immediately removed flatpak. Then there were updates available in Update Manager, which I installed. Then running mintinstall gave the above error. I did not install/remove mintinstall itself.

Then I re-installed and re-removed flatpak. Everything OK. mintinstall launches. Few days later I installed some available updates from Update Manager again. Same problem again. And so on. This happened 4-5 times since the Beta started. Probably would happen more often but I wasn't paying attention (since I never use Flatpak or Software Manager).

What if you remove gir1.2-flatpak-1.0 along with flatpak?

I'll try that! Gotta wait until the next available update...

[Harry-W-Haines-III]

Did a quick fresh install, removed flatpak and gir1.2-flatpak-1.0, did some updates and then launched mintinstall from the command prompt.

mintinstall
MintInstall: Detected system architecture: 'x86_64'
No flatpak support, install flatpak and gir1.2-flatpak-1.0 and restart mintinstall to enable it.
Installer: Generating new pkgcache
Installer: Processing APT packages for cache took 1157.129 ms
Full installer startup took 1431.313 ms
MintInstall: Cannot open reviews cache: [Errno 2] No such file or directory: '/home/harry/.cache/mintinstall/reviews.json'
MintInstall: Deleting old screenshots
MintInstall: Downloaded new reviews

Will wait for the original poster to confirm.