How to debug on GNOME Shell 3.6, 3.8 or newer

Question

I developed my own gnome-shell extension that worked on GNOME Shell 3.4 and GNOME Shell 3.6. It's not working on GNOME Shell 3.8 and I can't find out why because I don't know where to access to any logs.

On GNOME Shell 3.4, using Looking Glass, there was a 'Error' tab that was removed on the 3.6 and 3.8 version, and I can't see any errors. On the extensions tab, clicking on 'show the errors' says 'no errors'.

Launching the gnome-shell --replace for terminal doesn't show any errors either. But my extension is not displayed (the code is the same and works on GNOME 3.4 and 3.6).

How can I debug this in order to find what's wrong with my code?

Thanks!

The extension: https://github.com/Softcatala/TraductorGnomeShell

Answer 1

All output is redirected to stout/stderr this is captured in

.cache/gdm/session.log or .xsession-errors

Answer 2

Since Gnome 3.6+ the error message tab was removed from Looking Glass. On a Gnome 3.6+ system open a console and issue the command:

tail -f .xsession-errors

In your extension use the new logging syntax:

log('my message');

In your console you will then see:

JS LOG: my message

Answer 3

If you are using Fedora 19 log function mentioned in @mbokil answer writes to /var/log/messages

tail -f messages | grep 'localhost gnome-session'

will be your friend.