QVariantList crashed when call destructor

OcaJLSA

I'm new to Qt
I have a strange crash when a QVariantList is destroyed.
I write a small code to reproduice it.
I use another methode to decode the json array, but I want to understand why.
Qt 5.5.1
Visual Sudio 2017
Windows 10 64bit

const char cFile[] = { "{\"Ids\":[0,1,2]}" };

void TestJson(void)
{
	QByteArray Doc = QByteArray::fromRawData(cFile, strlen(cFile));
	QJsonDocument jDoc = QJsonDocument::fromJson(Doc);
	QJsonValue jVal = jDoc.object().value("Ids");
	if (!jVal.isArray())
		return;
	QJsonArray jArr = jVal.toArray();
	QVariantList list = jArr.toVariantList();
	return;	// crash !!!!!!!!!
}	

int main(int argc, char *argv[])
{
	TestJson();
}

Call stack

ucrtbased.dll!free_dbg_nolock(void * const block=0x00a840d8, const int block_use=16) Ligne 908	C++
ucrtbased.dll!_free_dbg(void * block=0x00a840d8, int block_use=-1) Ligne 1030	C++
AcqV7.exe!operator delete(void * block=0x00a840d8) Ligne 17	C++
AcqV7.exe!operator delete(void * block=0x00a840d8, unsigned int __formal=16) Ligne 15	C++
AcqV7.exe!QVariant::`scalar deleting destructor'(unsigned int)	C++
>	AcqV7.exe!QList<QVariant>::node_destruct(QList<QVariant>::Node * from=0x00a87798, QList<QVariant>::Node * to=0x00a877a0) Ligne 463	C++
AcqV7.exe!QList<QVariant>::dealloc(QListData::Data * data=0x00a87788) Ligne 836	C++
AcqV7.exe!QList<QVariant>::~QList<QVariant>() Ligne 797	C++
AcqV7.exe!TestJson() Ligne 67	C++
AcqV7.exe!main(int argc=1, char * * argv=0x00a880e8) Ligne 76	C++

kshegunov

Could you try with:

QByteArray Doc(cFile);

J.Hilk

@OcaJLSA

your example does not crash for me, 5.9.1 with MSCV2015(32b).

Exact Copy main.cpp:

#include <QByteArray>
#include <QJsonArray>
#include <QJsonDocument>
#include <QJsonObject>
#include <QVariant>

const char cFile[] = { "{\"Ids\":[0,1,2]}" };

void TestJson(void)
{
    QByteArray Doc = QByteArray::fromRawData(cFile, strlen(cFile));
    QJsonDocument jDoc = QJsonDocument::fromJson(Doc);
    QJsonValue jVal = jDoc.object().value("Ids");
    if (!jVal.isArray())
        return;
    QJsonArray jArr = jVal.toArray();
    QVariantList list = jArr.toVariantList();
    return;	// crash !!!!!!!!!
}

int main(int argc, char *argv[])
{
    TestJson();
}

TestJson.pro

QT += core
QT -= gui

CONFIG += c++11

TARGET = TestJson
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

DEFINES += QT_DEPRECATED_WARNINGS

kshegunov

In light of what @J-Hilk reports, you should search for a bug in the tracker to confirm this for Qt 5.5 and upgrade your Qt version.

OcaJLSA

It's impossible to update the Qt version, because my program will run on a wince7 device.
QT 5.9.1 is not compatible.
I will try to build on an other computer with QT 5.8
Thanks

VRonin

Tested with Qt 5.8 and 5.5. both working

Taz742

@OcaJLSA
5.7 5.5 work