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Bug
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Resolution: Unresolved
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P2: Important
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None
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6.10.0 RC
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None
As the title says, QFuture::cancelChain cancels the chain but it doesn't propagate the info down the chain.
The canceled info down the chain is very important as it's the only way to cancel the pending operation.
Here is a simple unit test to show the problem.
void MyTest::testQFuture_cancelChain()
{
QSemaphore start;
QSemaphore cont;
auto futureBuilder = [&](bool canceledB4, bool canceledAfter) {
return QtConcurrent::run(
[&](QPromise<void> &promise, bool canceledB4, bool canceledAfter) {
QCOMPARE(promise.isCanceled(), canceledB4);
start.release(1);
cont.acquire(1);
QCOMPARE(promise.isCanceled(), canceledAfter);
},
canceledB4, canceledAfter);
};
// 1st chain cancel
{
auto future = futureBuilder(false, true)
.then([] { QVERIFY(false); })
.onCanceled([] { QVERIFY(true); });
start.acquire(1);
future.cancelChain();
cont.release(1);
future.waitForFinished();
}
// 2nd chain cancel
{
auto future = futureBuilder(false, false)
.then([&](const QFuture<void> &innerFuture) {
QCOMPARE(innerFuture.isCanceled(), false);
start.release(1);
// should be canceled by "future.cancelChain()" below
cont.acquire(1);
QCOMPARE(innerFuture.isCanceled(), true);
})
.onCanceled([] { QVERIFY(false); })
.then([] { QVERIFY(false); })
.onCanceled([] { QVERIFY(true); });
start.acquire(1);
cont.release(1);
start.acquire(1);
future.cancelChain(); // should cancel the innerFuture from first ".then"
cont.release(1);
future.waitForFinished();
}
// Wrapped chain cancel
{
auto future = futureBuilder(false, false)
.then([&]() {
// This "wrapped future" should be canceled by "future.cancelChain()" below
return futureBuilder(false, true);
})
.unwrap()
.then([] { QVERIFY(false); })
.onCanceled([] { QVERIFY(true); });
start.acquire(1);
cont.release(1);
start.acquire(1);
future.cancelChain(); // should cancel the "wrapped" future from first ".then"
cont.release(1);
future.waitForFinished();
}
}