Re: gtk_notebook_map bug

[Owen Taylor <otaylor redhat com>]

Damon Chaplin <damon@karuna.freeserve.co.uk> writes:

> gtk_notebook_map () doesn't check if the tab label is visible before
> mapping it (GTK+ 1.2.6):
> 
> 	  if (page->tab_label && 
> 	      GTK_WIDGET_VISIBLE (page->child) && 
> 	      !GTK_WIDGET_MAPPED (page->tab_label))
> 	    gtk_widget_map (page->tab_label);
> 
> This results in warnings when a notebook is used with tabs hidden:
> 
>    Gtk-CRITICAL **: file gtkwidget.c: line 1584 (gtk_widget_map):
>            assertion `GTK_WIDGET_VISIBLE (widget) == TRUE' failed.
> 
> 
> Maybe this would be better (though I'm not sure how GtkNotebook fits
> together):
> 
> 	  if (page->tab_label && 
> 	      GTK_WIDGET_VISIBLE (page->child) && 
>               GTK_WIDGET_VISIBLE (page->tab_label) &&
> 	      !GTK_WIDGET_MAPPED (page->tab_label))
> 	    gtk_widget_map (page->tab_label);

Do you have an example that could be used to determine the code path
that was causing this warning?

The original code is pretty clearly bogus but I can't actually
reproduce the warning.

There are various things going on here:

 a) There doesn't seem to be the proper check here for notebook->show_tabs
 b) The notebook shows and hides the tab labels as well mapping/unmapping 
    them.

So, a safe rewrite for this section of code would look a bit like:

      children = notebook->children;

      while (children)
	{
	  page = children->data;
	  children = children->next;

	  if (page->tab_label)
            {
              if (notebook->show_tabs && GTK_WIDGET_VISIBLE (page->child))
                {
                  if (GTK_WIDGET_VISIBLE (page->tab_label))
                    {
                      if (!GTK_WIDGET_MAPPED (page->tab_label))
                         gtk_widget_map (page->tab_label);
                    }
                  else
                    gtk_widget_show (page->tab_label);
                }
              else 
                {
                  if (GTK_WIDGET_VISIBLE (page->tab_label))
                    GTK_WIDGET_HIDE (page->tab_label);
                }
	    }
         }

That is probably overkill, since the show/hide is also going on in
gtk_widget_size_request, so perhaps your fix is sufficient.  But I'd
like to have a some idea of exactly how the problem is occurring
before I start changing stuff.

Regards,
                                            Owen