[meld] Clean up undo handlers when closing a tab (closes bgo#678048)

[Kai Willadsen <kaiw src gnome org>]

commit 2348147babdf1b08361949add7645f2e07e303a3
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Thu Jun 14 07:41:36 2012 +1000

    Clean up undo handlers when closing a tab (closes bgo#678048)
    
    When the undo handling mechanisms were moved around in commit
    c8eb4d65c0bbbf3168250a2672c1f786e650cd67 the tab closing case wasn't
    dealt with.
    
    While tab removal does trigger a switch-out, and could theoretically
    be handled in the switch-page handler, there's no way to get at the
    page being switched from if that page has been removed. Therefore, we
    add a simple clean up of the signal handlers in try_remove_page.

 meld/meldwindow.py |   19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)
---
diff --git a/meld/meldwindow.py b/meld/meldwindow.py
index f393655..1bffda0 100644
--- a/meld/meldwindow.py
+++ b/meld/meldwindow.py
@@ -583,13 +583,20 @@ class MeldWindow(gnomeglade.Component):
         "See if a page will allow itself to be removed"
         response = page.on_delete_event(appquit)
         if response != gtk.RESPONSE_CANCEL:
-            self.scheduler.remove_scheduler( page.scheduler )
-            i = self.notebook.page_num( page.widget )
-            assert(i>=0)
-            # If the page we're removing is the current page, we need to trigger a switch out
-            if self.notebook.get_current_page() == i:
+            self.scheduler.remove_scheduler(page.scheduler)
+            page_num = self.notebook.page_num(page.widget)
+            assert page_num >= 0
+
+            # If the page we're removing is the current page, we need to
+            # disconnect and clear undo handlers, and trigger a switch out
+            if self.notebook.get_current_page() == page_num:
+                page.disconnect(self.diff_handler)
+                for handler in self.undo_handlers:
+                    page.undosequence.disconnect(handler)
+                self.undo_handlers = tuple()
                 page.on_container_switch_out_event(self.ui)
-            self.notebook.remove_page(i)
+
+            self.notebook.remove_page(page_num)
             if self.notebook.get_n_pages() == 0:
                 self.widget.set_title("Meld")
         return response