If the viewcvs.conf file contains in invalid setting of 'default_root',

viewcvs issues a very poor error message.  I've tried to improve that by
adding a simple print statement.

Ted Hobson wrote to the viewcvs users mailing list:
> Hi, I'm hoping I could get a little help here. I've installed viewcvs
[...]
> viewcvs.cgi and was returned the following error messages.
>
>       Python Exception Occurred
>
> Traceback (innermost last):
[...]
> in __init__
>     self.cvsroot = cfg.general.cvs_roots[self.cvsrep]
> KeyError: Development
>
> The lines of code it points to don't really help me at all. Could
> somebody explain what these lines are doing and what may be wrong?


git-svn-id: http://viewvc.tigris.org/svn/viewvc/trunk@226 8cb11bc2-c004-0410-86c3-e597b4017df7

lib/viewcvs.py

@@ -168,7 +168,12 @@ class Request:
 
     # set up the CVS repository to use
     self.cvsrep = query_dict.get('cvsroot', cfg.general.default_root)
-    self.cvsroot = cfg.general.cvs_roots[self.cvsrep]
+    try:
+      self.cvsroot = cfg.general.cvs_roots[self.cvsrep]
+    except KeyError:
+      print "To the administrator: Probably the settings of 'cvs_roots' and "
+      print "'default_root' are misconfigured in the viewcvs.conf file."
+      raise
 
     self.full_name = self.cvsroot + '/' + where