`webbrowser::open` returns `Ok(())` even when the web browser doesn't open

[mfreeborn]

I'm on Ubuntu 24.04 and my default browser is Firefox which was installed by default using snap.

I somehow got into the position where the snapd.apparmor service had exited, which didn't seem otherwise seem to affect my usage of my computer, including Firefox, outside of this issue.

In this state, calling webbrowser::open, returned Ok(()), but the browser didn't open (nor would it create a new tab if the browser was already open at the time of the call).

I managed to get some logging output by setting BrowserOptions::with_suppress_output(false), and the following was printed to my terminal:

snap-confine is packaged without necessary permissions and cannot continue required permitted capability cap_dac_override not found in current capabilities

Restarting the snapd.apparmor process fixed the problem, but I would have expected webbrowser to return an Err(_) rather than silently fail.

[amodm]

Can you share the full browser command that was logged, if there's nothing too sensitive in it?

[mfreeborn]

Hmm, I actually can't reproduce this if I now manually set the apparmor service to active (exited), so there must have been more to it than that...

The only additional output that followed the quote in the original post was to list the current capabilities, which looked something like:

current capabilities:
(
=
)

i.e. basically blank.

I'm not sure how much can be done about this without being able to reproduce it.

[amodm]

No problem. I'm going to play around with a few scenarios to see if I can reproduce this over the next few days.