Delete printer hangs

[tim-seoss]

Debian 11 (x86-64) with hplip-printer-app snap rev 788:

1. Create printer (USB attached LJ1015) via web UI.
2. Press "Delete Printer" button on web UI.
3. Press "Confirm Delete Printer" button

Process never returns, and web-UI is unresponsive. Can be recovered with snap restart hplip-printer-app - which completes after 70 seconds (maybe some sort of timeout).

Trying hplip-printer-app delete after the restart returns immediately, but then hplip-printer-app printers also hangs (returns with no output after 61 seconds).

Also tried removing and re-installing the snap, and same thing recurred...

[vsessink]

It's worse: hplip-printer-app printers stops functioning right after having clicked "remove printer" from the web interface. I.e. immediately after the web interface hangs, the printers will not show up.

Trying to stop the snap (snap stop hplip-printer-app) does the following:

2024-02-02T09:11:50+01:00 systemd[1]: Stopping Service for snap application hplip-printer-app.hplip-printer-app-server...
2024-02-02T09:13:00+01:00 systemd[1]: snap.hplip-printer-app.hplip-printer-app-server.service: State 'final-sigterm' timed out. Killing.
2024-02-02T09:13:00+01:00 systemd[1]: snap.hplip-printer-app.hplip-printer-app-server.service: Killing process 58436 (hplip-printer-a) with signal SIGKILL.
2024-02-02T09:13:00+01:00 systemd[1]: snap.hplip-printer-app.hplip-printer-app-server.service: Killing process 58563 (libusb_event) with signal SIGKILL.
2024-02-02T09:13:00+01:00 systemd[1]: snap.hplip-printer-app.hplip-printer-app-server.service: Failed with result 'timeout'.
2024-02-02T09:13:00+01:00 systemd[1]: Stopped Service for snap application hplip-printer-app.hplip-printer-app-server.
2024-02-02T09:13:00+01:00 systemd[1]: snap.hplip-printer-app.hplip-printer-app-server.service: Consumed 46.372s CPU time.

Using --edge (snap install hplip-printer-app --edge) seems to help, this installs 3.22.10-3 at time of writing. Please note that I'm absolutely positive that I did see the behaviour with this version, too. But unfortunately I'm unable to reproduce it.