check if the regexps exist before trying to use them (lots of "None"s being highlighted because of no checking)"

mitterlib/ui/helpers/gtk_messagegrid.py

@@ -187,25 +187,28 @@ class MessageGrid(gtk.ScrolledWindow, gobject.GObject):
                 message_values['message'])
 
         # highlight users
-        user_mask = '(%s)' % (data.user_regexp)
-        user_re = re.compile(user_mask, re.I)
-        mask = r'<span foreground="%s">\1</span>' % (self.user_color)
-        message_values['message'] = user_re.sub(mask,
-                message_values['message'])
+        if data.user_regexp:
+            user_mask = '(%s)' % (data.user_regexp)
+            user_re = re.compile(user_mask, re.I)
+            mask = r'<span foreground="%s">\1</span>' % (self.user_color)
+            message_values['message'] = user_re.sub(mask,
+                    message_values['message'])
 
         # highlight groups
-        group_mask = '(%s)' % (data.group_regexp)
-        group_re = re.compile(group_mask, re.I)
-        mask = r'<span foreground="%s">\1</span>' % (self.group_color)
-        message_values['message'] = group_re.sub(mask,
-                message_values['message'])
+        if data.group_regexp:
+            group_mask = '(%s)' % (data.group_regexp)
+            group_re = re.compile(group_mask, re.I)
+            mask = r'<span foreground="%s">\1</span>' % (self.group_color)
+            message_values['message'] = group_re.sub(mask,
+                    message_values['message'])
 
         # highlight tags
-        tag_mask = '(%s)' % (data.tag_regexp)
-        tag_re = re.compile(tag_mask, re.I)
-        mask = r'<span foreground="%s">\1</span>' % (self.tag_color)
-        message_values['message'] = tag_re.sub(mask,
-                message_values['message'])
+        if data.tag_regexp:
+            tag_mask = '(%s)' % (data.tag_regexp)
+            tag_re = re.compile(tag_mask, re.I)
+            mask = r'<span foreground="%s">\1</span>' % (self.tag_color)
+            message_values['message'] = tag_re.sub(mask,
+                    message_values['message'])
 
         # use a different highlight for the current user
         # TODO: How to handle this with several networks?