Crash when closing App : RemovePendingEventHandler

[jds210]

When closing an App, the wxApp instance is destroyed, but the destructor of wxEvtHandler (base class) may call RemovePendingEventHandler without checking if it is 'this'. 

If the wxEvtHandler is the App, then errors occur because members of the wxApp object have already been destroyed (notably the critical section objects). Maybe wxEvtHandler should not call RemovePendingEventHandler if the wxTheApp == this?

[jds210]

Proposed patch fixing #11525

[vadz]

I think this

src/common/appbase.cpp

@@ -154 +154 @@
 
 wxAppConsoleBase::~wxAppConsoleBase()
 {
+    // we're being destroyed and using this object from now on may not work or
+    // even crash so don't leave dangling pointers to it
+    ms_appInstance = NULL;
+
     delete m_traits;
 }
 

would be a better fix: if wxTheApp is non-NULL it should be valid.

Could you please test if it fixes your problem?

Thanks!

[jds210]

Your patch fixes it - Thanks.

[VZ]

(In [62813]) Reset wxTheApp when starting to destroy the object it points to.

Using wxTheApp when the corresponding object is already half destroyed can't
be a good idea so reset it to NULL as soon as possible.

Closes #11525.