QProgressBar update in QThread quitting crashes - qt

Question

I have the following code that works as expected. It updates the progress bar value in each for loop. The only issue I have is when I'm done and call emit ProcessUserRowsFinished() in the method OnProcessUserRowsStarted the program crashes.
class UsersProcess: public QObject
{
Q_OBJECT
public:
UsersProcess(CTCore::DBConnect* db_context, UserSettingsMap user_settings_map);
void SetProgressBar(QProgressBar *progress_bar);
private:
QProgressBar *progressBar;
QSharedPointer<QList<CTCoreZen::User>> listUsers;
QScopedPointer<QThread> threadRowWorker;
signals:
void ProcessUserRowsFinished();
void ProgressBarSetValue(int value);
}
void UsersProcess::SetProgressBar(QProgressBar *progress_bar)
{
this->progressBar = progress_bar;
}
void UsersProcess::OnUserListSuccess(QList<CTCoreZen::User> *users)
{
this->listUsers.reset(users);
this->progressBar->setVisible(true);
this->progressBar->setTextVisible(true);
this->progressBar->setMinimum(0);
this->progressBar->setMaximum(this->listUsers->size());
this->progressBar->setValue(0);
this->threadRowWorker.reset(new QThread());
this->moveToThread(this->threadRowWorker.data());
connect(this->threadRowWorker.data(), &QThread::started, this, &UsersProcess::OnProcessUserRowsStarted);
connect(this, &UsersProcess::ProgressBarSetValue, this->progressBar, &QProgressBar::setValue);
connect(this, &UsersProcess::ProcessUserRowsFinished, this->threadRowWorker.data(), &QThread::quit);
connect(this, &UsersProcess::ProcessUserRowsFinished, this, &UsersProcess::deleteLater);
connect(this->threadRowWorker.data(), &QThread::finished, this->threadRowWorker.data(), &QThread::deleteLater);
this->threadRowWorker->start();
}
void UsersProcess::OnProcessUserRowsStarted()
{
int row = 0;
UsersData userData(this->dbContext);
int maxRows = this->listUsers->size();
for(auto iter = this->listUsers->begin(); iter != this->listUsers->end(); ++iter)
{
row++;
emit this->ProgressBarSetValue(row);
}
emit ProcessUserRowsFinished();
}

Answer 1

This is because of your thread has been deleted.
This call deletes the instance of class UsersProcess and QScopedPointer deletes the thread.
connect(this, &UsersProcess::ProcessUserRowsFinished, this, &UsersProcess::deleteLater);
But you also have this connections
connect(this, &UsersProcess::ProcessUserRowsFinished, this->threadRowWorker.data(), &QThread::quit);
connect(this->threadRowWorker.data(), &QThread::finished, this->threadRowWorker.data(), &QThread::deleteLater);
When one of this events fires the thread is already deleted.