Item14237: Merge commit '66d050726f5daac96d7f60e9b8d8eb9b97226935' in…

…to Item14237

* commit '66d050726f5daac96d7f60e9b8d8eb9b97226935':
  Item14152: Fixed attempt to use undef app attribute at cleanup.

core/lib/Foswiki/Aux/Callbacks.pm

@@ -98,14 +98,23 @@ around BUILD => sub {
 
 before DEMOLISH => sub {
     my $this = shift;
-
-    #$this->_traceMsg("Callbacks DEMOLISH");
+    my ($in_global) = @_;
 
     # Cleanup all callbacks registed by this object.
-    my $appHeap = $this->_getApp->heap;
-
-    foreach my $cbName ( keys %{ $appHeap->{_aux_registered_callbacks} } ) {
-        $this->deregisterCallback($cbName);
+    unless ($in_global) {
+        my $app = $this->_getApp;
+
+        # The application object could have been already destroyed at this
+        # moment. This is normal for auto-destruction.
+        if ( defined $app ) {
+            my $appHeap = $app->heap;
+
+            foreach
+              my $cbName ( keys %{ $appHeap->{_aux_registered_callbacks} } )
+            {
+                $this->deregisterCallback($cbName);
+            }
+        }
     }
 };