Fix crash if menu is deleted while menu is open (SGR #3503).

This can happen if a menu widget (e.g. Fl_Choice) is deleted in a
timer callback while the menu is open (pulldown active).

1 files changed, 8 insertions, 1 deletions

diff --git a/src/Fl_Menu.cxx b/src/Fl_Menu.cxx
index 1d7f47672..b3e1f5c65 100644
--- a/src/Fl_Menu.cxx
+++ b/src/Fl_Menu.cxx
@@ -867,6 +867,10 @@ const Fl_Menu_Item* Fl_Menu_Item::pulldown(
     int menubar) const {
   Fl_Group::current(0); // fix possible user error...
 
+  // track the Fl_Menu_ widget to make sure we notice if it gets
+  // deleted while the menu is open (STR #3503)
+  Fl_Widget_Tracker wp((Fl_Widget *)pbutton);
+
   button = pbutton;
   if (pbutton && pbutton->window()) {
     for (Fl_Window* w = pbutton->window(); w; w = w->window()) {
@@ -903,7 +907,8 @@ const Fl_Menu_Item* Fl_Menu_Item::pulldown(
   initial_item = pp.current_item;
   if (initial_item) goto STARTUP;
 
-  // the main loop, runs until p.state goes to DONE_STATE:
+  // the main loop: runs until p.state goes to DONE_STATE or the menu
+  // widget is deleted (e.g. from a timer callback, see STR #3503):
   for (;;) {
 
     // make sure all the menus are shown:
@@ -920,6 +925,8 @@ const Fl_Menu_Item* Fl_Menu_Item::pulldown(
     {
       const Fl_Menu_Item* oldi = pp.current_item;
       Fl::wait();
+      if (wp.deleted()) // menu widget has been deleted (STR #3503)
+	break;
       if (pp.state == DONE_STATE) break; // done.
       if (pp.current_item == oldi) continue;
     }