(should) Fix #2175 ; prevent bugs caused by tab gaps

src/core.py

@@ -1012,6 +1012,10 @@ class Core(object):
         if config.get('create_gaps', 'false').lower() == 'true':
             if nb >= len(self.tabs) - 1:
                 self.tabs.remove(tab)
+                nb -= 1
+                while not self.tabs[nb]: # remove the trailing gaps
+                    self.tabs.pop()
+                    nb -= 1
             else:
                 self.tabs[nb] = tabs.GapTab()
         else:
@@ -1506,6 +1510,8 @@ class Core(object):
         self.current_tab().on_lose_focus()
         if isinstance(nb, int):
             if 0 <= nb < len(self.tabs):
+                if not self.tabs[nb]:
+                    return
                 self.current_tab_nb = nb
         else:
             for tab in self.tabs:

src/tabs.py

@@ -269,7 +269,7 @@ class Tab(object):
         """
         Called on each screen refresh (when something has changed)
         """
-        raise NotImplementedError
+        pass
 
     def get_name(self):
         """
@@ -389,6 +389,9 @@ class GapTab(Tab):
     def get_name(self):
         return ''
 
+    def refresh(self):
+        log.debug('WARNING: refresh() called on a gap tab, this should not happen')
+
 class ChatTab(Tab):
     """
     A tab containing a chat of any type.
@@ -611,7 +614,7 @@ class ChatTab(Tab):
             return self._text_buffer.messages
 
     def command_say(self, line):
-        raise NotImplementedError
+        pass
 
     def on_line_up(self):
         return self.text_win.scroll_up(1)