Re: Issue 802: menubar-x.c assertion failure
On Wed, Jan 16, 2013 at 6:58 PM, Stephen J. Turnbull <stephen(a)xemacs.org> wrote:
The problem with this simple patch is that you may just be pushing
the
crash around. There's another call to compute_menubar_data later in
menubar-x.c at line 596; make sure it is similarly protected if
necessary. Grep says those are the only calls (it's static so all
calls are in menubar-x.c).
There probably also should be a comment on compute_menubar_data
warning that it can return NULL.
I wonder if it *should* be able to return NULL, or if there's a bug
elsewhere.
I believe that returning NULL is all it can do if it is handed a
broken menu specification. Ben's error wrapping stuff is right in the
middle of the call stack, so probably this code used to (unsafely)
throw Lisp errors right past compute_menubar_data, so the assert was
correct. With the current code structure, though, we need to keep
unraveling the stack upwards until we reach a point where the delayed
error can be rethrown and handled properly (by displaying it in
*Warnings*).
I think. At least it seems to work that way when handed the broken
ESS menu specification.
Try this patch on for size:
diff -r 8b5bdc8aebfd src/ChangeLog
--- a/src/ChangeLog Sat Jan 05 02:11:23 2013 +0900
+++ b/src/ChangeLog Fri Jan 18 15:14:06 2013 -0700
＠＠ -1,3 +1,9 ＠＠
+2013-01-16 Jerry James <james(a)xemacs.org>
+
+ * menubar-x.c (set_frame_menubar): when a menubar specification has an
+ error, don't fail an assert() and bring XEmacs down. Instead, return
+ 0 to just skip the faulty menu and show any errors in *Warnings*.
+
2013-01-04 Stephen J. Turnbull <stephen(a)xemacs.org>
* XEmacs 21.5.33 "horseradish" is released.
diff -r 8b5bdc8aebfd src/menubar-x.c
--- a/src/menubar-x.c Sat Jan 05 02:11:23 2013 +0900
+++ b/src/menubar-x.c Fri Jan 18 15:14:06 2013 -0700
＠＠ -516,6 +516,9 ＠＠
}
}
+/* Returns the converted menubar, or NULL if an error is encountered while
+ * converting the Lisp menu specification.
+ */
static widget_value *
compute_menubar_data (struct frame *f, Lisp_Object menubar, int deep_p)
{
＠＠ -573,7 +576,8 ＠＠
menubar_visible = !NILP (w->menubar_visible_p);
data = compute_menubar_data (f, menubar, deep_p);
- assert (data && (data->next || data->contents));
+ if (!data || (!data->next && !data->contents))
+ return 0;
if (!FRAME_X_MENUBAR_ID (f))
FRAME_X_MENUBAR_ID (f) = new_lwlib_id ();
＠＠ -594,6 +598,8 ＠＠
{
free_popup_widget_value_tree (data);
data = compute_menubar_data (f, menubar, 1);
+ if (!data || (!data->next && !data->contents))
+ return 0;
}
--
Jerry James
http://www.jamezone.org/
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