[Thomas Spura]

Recently slim doesn't create an ~/.Xauthority file by default, so the user is forced to do this on his/her own.
If not, e.g. gmixer is crashing...

Would it be possible to set reasonable default values, when there is no ~/.Xauthority file instead of crashing?

As a reference see:
https://bugzilla.redhat.com/show_bug.cgi?id=552491

Hmm, that's a tricky one - I'm not sure there is a sensible default as you (probably) need the cookie in order to connect. However, perhaps it's possible to get the cookie another way - if you run "xauth list" do you get something like:
machine.domain/unix:0 MIT-MAGIC-COOKIE-1 2d3c0359e1744ca68d2388d68aa14c52

If so, there's an old method to get the cookie using a system call to xauth that you could try. Edit Xlib/support/unix_connect.py and change the last line to "get_auth = old_get_auth". I've not tested it, but that should use the xauth list output instead of parsing ~/.Xauthority.

If that works, let me know and maybe we can add that as a last-resort fallback if Xauthority parsing fails.

The old method seems to work!

Quoting from the bugzilla url from above:
"This appears to have solved the problem."

This is the patch I applied (which should solve the problem completely), isn't it?
$ cat python-xlib-0.15rc1-xauthority.patch
Index: Xlib/support/unix_connect.py
===================================================================
--- Xlib/support/unix_connect.py
+++ Xlib/support/unix_connect.py 2010-09-03 00:49:15.066186229 +0200
@@ -112,7 +112,11 @@
family = xauth.FamilyLocal
addr = socket.gethostname()

- au = xauth.Xauthority()
+ try:
+ au = xauth.Xauthority()
+ except error.XauthError:
+ return old_get_auth(sock, dname, host, dno)
+
while 1:
try:
return au.get_best_auth(family, addr, dno)

sourceforge, seems to not like spaces, so here is the URL of the patch:
http://tomspur.fedorapeople.org/python-xlib-0.15rc1-xauthority.patch