[mutter] keybindings: Check for a handler before using it

[Olivier Fourdan <ofourdan src gnome org>]

commit 0706e021f5bd82cf4c9b2c0d2916d272f3cba406
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Tue Sep 24 16:55:25 2019 +0200

    keybindings: Check for a handler before using it
    
    The `process_event()` would check for a existing keybinding handler and
    abort if there is none, however the test is done after the handler had
    been accessed, hence defeating the purpose of the check.
    
    Move the check to verify there is an existing keybinding handler before
    actually using it.
    
    https://gitlab.gnome.org/GNOME/mutter/issues/823

 src/core/keybindings.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
---
diff --git a/src/core/keybindings.c b/src/core/keybindings.c
index a5a60e8cd..b9377bfff 100644
--- a/src/core/keybindings.c
+++ b/src/core/keybindings.c
@@ -1955,6 +1955,9 @@ process_event (MetaDisplay          *display,
       (!window && binding->flags & META_KEY_BINDING_PER_WINDOW))
     goto not_found;
 
+  if (binding->handler == NULL)
+    meta_bug ("Binding %s has no handler\n", binding->name);
+
   if (display->focus_window &&
       !(binding->handler->flags & META_KEY_BINDING_NON_MASKABLE))
     {
@@ -1980,12 +1983,9 @@ process_event (MetaDisplay          *display,
       return TRUE;
     }
 
-  if (binding->handler == NULL)
-    meta_bug ("Binding %s has no handler\n", binding->name);
-  else
-    meta_topic (META_DEBUG_KEYBINDINGS,
-                "Running handler for %s\n",
-                binding->name);
+  meta_topic (META_DEBUG_KEYBINDINGS,
+              "Running handler for %s\n",
+              binding->name);
 
   /* Global keybindings count as a let-the-terminal-lose-focus
    * due to new window mapping until the user starts