Lua events not propagating to event handlers outside of the wxLuaState itself

[Zekkers]

I recently merged up to the latest wxLua and noticed that I was no longer getting events like wxEVT_LUA_ERROR which I capture to log and display.

I checked the diff of the merge and noticed the changes from commit bde906e39b19f5179c66c44c9b681f40bf4475e0 . I reverted just that commit in my own repo, and the events started working again.

The frame in question is largely based on the wxLuaStandaloneApp with respect to the event handling.

Looks like wxDEFINE_EVENT calls in wxlstate.h could be executed multiple times if included by different modules, so the event IDs are not matching.

[pkulchenko]

@Zekkers, thank you for the report; this is interesting. I'm not sure why it would behave this way, as there is definitely #ifndef _WXLSTATE_H_ check at the top of wxlstate.h file, so it should only be processed once. I wonder if it makes any difference for you if you move the lines in the offending change to the end of the file, as is shown in the following diff:

diff --git a/wxLua/modules/wxlua/wxlstate.h b/wxLua/modules/wxlua/wxlstate.h
index eff8a51..405edba 100644
--- a/wxLua/modules/wxlua/wxlstate.h
+++ b/wxLua/modules/wxlua/wxlstate.h
@@ -792,18 +792,6 @@ public:
     lua_Debug *m_lua_Debug;
 };
 
-#if wxCHECK_VERSION(3,0,0)
-wxDEFINE_EVENT(wxEVT_LUA_CREATION, wxLuaEvent);
-wxDEFINE_EVENT(wxEVT_LUA_PRINT, wxLuaEvent);
-wxDEFINE_EVENT(wxEVT_LUA_ERROR, wxLuaEvent);
-wxDEFINE_EVENT(wxEVT_LUA_DEBUG_HOOK, wxLuaEvent);
-#else
-DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_CREATION)
-DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_PRINT)
-DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_ERROR)
-DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_DEBUG_HOOK)
-#endif
-
 #if wxCHECK_VERSION(3,0,0)
 // A wxLuaState is being created, sent at the end of
 //   wxLuaState(wxEvtHandler, win id) or Create(wxEvtHandler, win id)
@@ -843,4 +831,16 @@ typedef void (wxEvtHandler::*wxLuaEventFunction)(wxLuaEvent&);
 #define EVT_LUA_ERROR(id, fn)      wx__DECLARE_WXLUAEVT(wxEVT_LUA_ERROR,      id, fn)
 #define EVT_LUA_DEBUG_HOOK(id, fn) wx__DECLARE_WXLUAEVT(wxEVT_LUA_DEBUG_HOOK, id, fn)
 
+#if wxCHECK_VERSION(3,0,0)
+wxDEFINE_EVENT(wxEVT_LUA_CREATION, wxLuaEvent);
+wxDEFINE_EVENT(wxEVT_LUA_PRINT, wxLuaEvent);
+wxDEFINE_EVENT(wxEVT_LUA_ERROR, wxLuaEvent);
+wxDEFINE_EVENT(wxEVT_LUA_DEBUG_HOOK, wxLuaEvent);
+#else
+DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_CREATION)
+DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_PRINT)
+DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_ERROR)
+DEFINE_LOCAL_EVENT_TYPE(wxEVT_LUA_DEBUG_HOOK)
+#endif
+
 #endif // _WXLSTATE_H_

[pkulchenko]

@Zekkers, BTW, do you have a code sample to test this (when it's working or not working)?

[pkulchenko]

@Zekkers, do you have any update on this or a sample I can use to test this? Thanks!

[Zekkers]

Sorry. I'll try and put something together tomorrow. Completely forgot about this!

[Zekkers]

So, under MSVC, trying to move the definitions to the end of the wxlstate.h file results in linker warnings for libraries, and errors for binaries.

For library linking, it comes back with warnings:

14:18:14:335	6>LuaHttpRequest.obj : warning LNK4006: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_CREATION" (?wxEVT_LUA_CREATION@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in LuaHttpResponse.obj; second definition ignored
14:18:14:335	6>LuaHttpRequest.obj : warning LNK4006: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_PRINT" (?wxEVT_LUA_PRINT@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in LuaHttpResponse.obj; second definition ignored
14:18:14:335	6>LuaHttpRequest.obj : warning LNK4006: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_ERROR" (?wxEVT_LUA_ERROR@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in LuaHttpResponse.obj; second definition ignored
14:18:14:335	6>LuaHttpRequest.obj : warning LNK4006: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_DEBUG_HOOK" (?wxEVT_LUA_DEBUG_HOOK@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in LuaHttpResponse.obj; second definition ignored

and for binary linking, comes back with:

14:23:07:407	1>wxLua.lib(wxlua_bind.obj) : error LNK2005: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_CREATION" (?wxEVT_LUA_CREATION@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in App.obj
14:23:07:407	1>wxLua.lib(wxlua_bind.obj) : error LNK2005: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_PRINT" (?wxEVT_LUA_PRINT@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in App.obj
14:23:07:407	1>wxLua.lib(wxlua_bind.obj) : error LNK2005: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_ERROR" (?wxEVT_LUA_ERROR@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in App.obj
14:23:07:407	1>wxLua.lib(wxlua_bind.obj) : error LNK2005: "class wxEventTypeTag<class wxLuaEvent> const wxEVT_LUA_DEBUG_HOOK" (?wxEVT_LUA_DEBUG_HOOK@@3V?$wxEventTypeTag@VwxLuaEvent@@@@B) already defined in App.obj

Even though the definitions are in an include guard, including the file still implies that you're using the contents. So the compiler will still 'do' what was in there. It just doesn't have to re-parse. So, because wxDEFINE_EVENT generates a public variable wxEventTypeTag<wxLuaEvent> wxEVT_LUA_DEBUG_HOOK for example, its doing the same for every inclusion of this file.

I recompiled with the definitions before the declarations, and checked the map file. It shows multiple initialisers, apparently one for each translation unit:

0003:000007e0       ?wxEVT_LUA_CREATION$initializer$@@3P6AXXZEA 00000001428f47e0     App.obj
0003:00000a08       ?wxEVT_LUA_CREATION$initializer$@@3P6AXXZEA 00000001428f4a08     LuaConsole.obj
0003:00000a48       ?wxEVT_LUA_CREATION$initializer$@@3P6AXXZEA 00000001428f4a48     LuaInstanceWindow.obj
etc. etc.

So, to the best of my knowledge, events created in different translation units do not match the ones in the interested party.

[valid-ptr]

This commit: bde906e breaks static linking and must be reverted.

Definitions (wxDEFINE_EVENT) must be in cpp files -> object files -> static archives.

[solemnwarning]

Had to revert this in my project too, opened a PR for it: #140