QFuture: the result type doesn't have to be a default-constructible

Added asserts to insure the invariant declared in the documentation.
Canceled future object is not valid, hence we don't need to handle
this case separately.

Fixes: QTBUG-83389
Change-Id: Ib0653ef40cd3135574a91740e4ce2c6dc4da8a71
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 2 insertions, 13 deletions

diff --git a/src/corelib/thread/qfutureinterface.h b/src/corelib/thread/qfutureinterface.h
index 04828609ba..02f854e0de 100644
--- a/src/corelib/thread/qfutureinterface.h
+++ b/src/corelib/thread/qfutureinterface.h
@@ -339,13 +339,8 @@ inline QList<T> QFutureInterface<T>::results()
 template<typename T>
 T QFutureInterface<T>::takeResult()
 {
-    if (isCanceled()) {
-        exceptionStore().throwPossibleException();
-        return {};
-    }
+    Q_ASSERT(isValid());
 
-    if (!isValid())
-        return {};
     // Note: we wait for all, this is intentional,
     // not to mess with other unready results.
     waitForResult(-1);
@@ -362,13 +357,7 @@ T QFutureInterface<T>::takeResult()
 template<typename T>
 std::vector<T> QFutureInterface<T>::takeResults()
 {
-    if (isCanceled()) {
-        exceptionStore().throwPossibleException();
-        return {};
-    }
-
-    if (!isValid())
-        return {};
+    Q_ASSERT(isValid());
 
     waitForResult(-1);
     std::vector<T> res;