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Fix binding guard in property evaluation

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The comment for keepAlive means that it should be destroyed after the
updateGuard goes out of scope and restores its value. In this case
keepAlive should be actually created *before* updateGuard, not after it.

Pick-to: 6.2 6.2.0
Task-number: QTBUG-96303
Change-Id: I4f8e67b49c1d6579228e22111105fb936f1f94db
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
This commit is contained in:
Ivan Solovev 2021-09-09 17:01:14 +02:00
parent b5a23e88be
commit 248f0aad1c
1 changed files with 9 additions and 9 deletions
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18
src/corelib/kernel/qproperty_p.h
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@ -707,18 +707,18 @@ inline void QPropertyBindingPrivate::evaluateRecursive_inline(QBindingStatus *st
return;
}
QScopedValueRollback<bool> updateGuard(updating, true);
/*
* Evaluating the binding might lead to the binding being broken. This can
* cause ref to reach zero at the end of the function. However, the
* updateGuard's destructor will then still trigger, trying to set the
* updating bool to its old value
* To prevent this, we create a QPropertyBindingPrivatePtr which ensures
* that the object is still alive when updateGuard's dtor runs.
*/
* Evaluating the binding might lead to the binding being broken. This can
* cause ref to reach zero at the end of the function. However, the
* updateGuard's destructor will then still trigger, trying to set the
* updating bool to its old value
* To prevent this, we create a QPropertyBindingPrivatePtr which ensures
* that the object is still alive when updateGuard's dtor runs.
*/
QPropertyBindingPrivatePtr keepAlive {this};
QScopedValueRollback<bool> updateGuard(updating, true);
QtPrivate::BindingEvaluationState evaluationFrame(this, status);
auto bindingFunctor = reinterpret_cast<std::byte *>(this) +