Crash on deletion of QScriptEngine object

**The_Fallen** · 10th March 2010, 21:05

Hi,

on start of my app I create a new QScriptEngine object, use it for a lot of stuff and destroy it before quitting the app. Unfortunately the app crashes when coming to the line with the delete.
I do so many things with the object during its lifetime, and I don't have any clue, what could be the reason for this. That's also why I can't post any source code here... Any ideas anybody? Thanks.

Cheers,
Tim

**wysota** · 11th March 2010, 07:55

Please post the stack backtrace from the debugger.

**The_Fallen** · 11th March 2010, 09:05

Qt Code:

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0	~QObject	qobject.cpp	954	0x6a20d95b	
1	~MainWindow	mainwindow.cpp	166	0x00402d25	
2	~QObjectDelegate	qscriptqobject.cpp	1156	0x0a5d2f70	
3	~Data	qscriptobject.cpp	42	0x0a5cadea	
4	~QScriptObject	qscriptobject.cpp	52	0x0a5caf11	
5	QTJSC::Heap::sweep<(QTJSC::HeapType)0>	Collector.cpp	1156	0x0a614e8f	
6	QTJSC::Heap::destroy	Collector.cpp	199	0x0a5530f7	
7	~QScriptEnginePrivate	qscriptengine.cpp	838	0x0a5b6277	
8	QScopedPointerDeleter<QObjectData>::cleanup	qscopedpointer.h	62	0x6a267efe	
9	~QScopedPointer	qscopedpointer.h	100	0x6a25e701	
10	~QObject	qobject.cpp	992	0x6a20cfd0	
11	~QScriptEngine	qscriptengine.cpp	1488	0x0a5b8d94	
12	~MainWindow	mainwindow.cpp	166	0x00402a75	
13	qMain	main.cpp	9	0x0040140d	
14	WinMain@16	qtmain_win.cpp	131	0x0046da72	
15	main		0	0x0046d798

0	~QObject	qobject.cpp	954	0x6a20d95b	
1	~MainWindow	mainwindow.cpp	166	0x00402d25	
2	~QObjectDelegate	qscriptqobject.cpp	1156	0x0a5d2f70	
3	~Data	qscriptobject.cpp	42	0x0a5cadea	
4	~QScriptObject	qscriptobject.cpp	52	0x0a5caf11	
5	QTJSC::Heap::sweep<(QTJSC::HeapType)0>	Collector.cpp	1156	0x0a614e8f	
6	QTJSC::Heap::destroy	Collector.cpp	199	0x0a5530f7	
7	~QScriptEnginePrivate	qscriptengine.cpp	838	0x0a5b6277	
8	QScopedPointerDeleter<QObjectData>::cleanup	qscopedpointer.h	62	0x6a267efe	
9	~QScopedPointer	qscopedpointer.h	100	0x6a25e701	
10	~QObject	qobject.cpp	992	0x6a20cfd0	
11	~QScriptEngine	qscriptengine.cpp	1488	0x0a5b8d94	
12	~MainWindow	mainwindow.cpp	166	0x00402a75	
13	qMain	main.cpp	9	0x0040140d	
14	WinMain@16	qtmain_win.cpp	131	0x0046da72	
15	main		0	0x0046d798

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Looking at this again I had an idea...
As you can see, the destructor of MainWindow appears twice in the stack backtrace. Then I realized that I'm wrapping the MainWindow object in a ScriptValue:

Qt Code:

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QScriptValue scriptMainWnd = engine->newQObject(mainWnd, QScriptEngine::ScriptOwnership);

QScriptValue scriptMainWnd = engine->newQObject(mainWnd, QScriptEngine::ScriptOwnership);

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Does the destructor of QScriptEngine also delete all the objects connected to its QScriptValues? Then of course this would make perfect sense, since the destruction of the QScriptEngine would yield the destruction of the MainWindow. But that's just a wild guess...

Cheers,
Tim