Remove return type of QState::addTransition(QAbstractTransition*)

Returning the input argument in a function can lead to confusion and
serves no purpose here. Instead, we'll mirror the API from
QMenu::addAction() overloads, where the overload that takes a
preconstructed object has a void return type.

Reviewed-by: Kent Hansen

3 files changed, 36 insertions, 23 deletions

diff --git a/src/corelib/statemachine/qstate.cpp b/src/corelib/statemachine/qstate.cpp
index bcd8364..ea20619 100644
--- a/src/corelib/statemachine/qstate.cpp
+++ b/src/corelib/statemachine/qstate.cpp
@@ -286,15 +286,14 @@ void QState::setErrorState(QAbstractState *state)
 
 /*!
   Adds the given \a transition. The transition has this state as the source.
-  This state takes ownership of the transition. If the transition is successfully
-  added, the function will return the \a transition pointer. Otherwise it will return null.
+  This state takes ownership of the transition. 
 */
-QAbstractTransition *QState::addTransition(QAbstractTransition *transition)
+void QState::addTransition(QAbstractTransition *transition)
 {
     Q_D(QState);
     if (!transition) {
         qWarning("QState::addTransition: cannot add null transition");
-        return 0;
+        return ;
     }
 
     transition->setParent(this);
@@ -303,18 +302,17 @@ QAbstractTransition *QState::addTransition(QAbstractTransition *transition)
         QAbstractState *t = targets.at(i).data();
         if (!t) {
             qWarning("QState::addTransition: cannot add transition to null state");
-            return 0;
+            return ;
         }
         if ((QAbstractStatePrivate::get(t)->machine() != d->machine())
             && QAbstractStatePrivate::get(t)->machine() && d->machine()) {
             qWarning("QState::addTransition: cannot add transition "
                      "to a state in a different state machine");
-            return 0;
+            return ;
         }
     }
     if (machine() != 0 && machine()->configuration().contains(this))
         QStateMachinePrivate::get(machine())->registerTransitions(this);
-    return transition;
 }
 
 /*!
@@ -379,7 +377,8 @@ QAbstractTransition *QState::addTransition(QAbstractState *target)
         return 0;
     }
     UnconditionalTransition *trans = new UnconditionalTransition(target);
-    return addTransition(trans);
+    addTransition(trans);
+    return trans;
 }
 
 /*!
diff --git a/src/corelib/statemachine/qstate.h b/src/corelib/statemachine/qstate.h
index 7a47447..781382d 100644
--- a/src/corelib/statemachine/qstate.h
+++ b/src/corelib/statemachine/qstate.h
@@ -76,7 +76,7 @@ public:
     QAbstractState *errorState() const;
     void setErrorState(QAbstractState *state);
 
-    QAbstractTransition *addTransition(QAbstractTransition *transition);
+    void addTransition(QAbstractTransition *transition);
     QSignalTransition *addTransition(QObject *sender, const char *signal, QAbstractState *target);
     QAbstractTransition *addTransition(QAbstractState *target);
     void removeTransition(QAbstractTransition *transition);
diff --git a/tests/auto/qstatemachine/tst_qstatemachine.cpp b/tests/auto/qstatemachine/tst_qstatemachine.cpp
index 31ab3af..fb6567a 100644
--- a/tests/auto/qstatemachine/tst_qstatemachine.cpp
+++ b/tests/auto/qstatemachine/tst_qstatemachine.cpp
@@ -286,8 +286,8 @@ void tst_QStateMachine::transitionToRootState()
     machine.addState(initialState);
     machine.setInitialState(initialState);
 
-    QAbstractTransition *trans = initialState->addTransition(new EventTransition(QEvent::User, &machine));
-    QVERIFY(trans != 0);
+    QAbstractTransition *trans = new EventTransition(QEvent::User, &machine);
+    initialState->addTransition(trans);
     QCOMPARE(trans->sourceState(), initialState);
     QCOMPARE(trans->targetState(), static_cast<QAbstractState *>(&machine));
 
@@ -310,7 +310,7 @@ void tst_QStateMachine::transitionFromRootState()
     QState *root = &machine;
     QState *s1 = new QState(root);
     EventTransition *trans = new EventTransition(QEvent::User, s1);
-    QCOMPARE(root->addTransition(trans), static_cast<QAbstractTransition *>(trans));
+    root->addTransition(trans);
     QCOMPARE(trans->sourceState(), root);
     QCOMPARE(trans->targetState(), static_cast<QAbstractState *>(s1));
 }
@@ -1155,7 +1155,7 @@ void tst_QStateMachine::stateEntryAndExit()
         QCOMPARE(t->targetState(), (QAbstractState*)s2);
         QCOMPARE(t->targetStates().size(), 1);
         QCOMPARE(t->targetStates().at(0), (QAbstractState*)s2);
-        QCOMPARE(s1->addTransition(t), (QAbstractTransition*)t);
+        s1->addTransition(t);
         QCOMPARE(t->sourceState(), (QState*)s1);
         QCOMPARE(t->machine(), &machine);
 
@@ -1173,7 +1173,7 @@ void tst_QStateMachine::stateEntryAndExit()
             s2->removeTransition(trans);
             QCOMPARE(trans->sourceState(), (QState*)0);
             QCOMPARE(trans->targetState(), (QAbstractState*)s3);
-            QCOMPARE(s2->addTransition(trans), trans);
+            s2->addTransition(trans);
             QCOMPARE(trans->sourceState(), (QState*)s2);
         }
 
@@ -3117,7 +3117,9 @@ void tst_QStateMachine::twoAnimatedTransitions()
     QState *s2 = new QState(&machine);
     s2->assignProperty(object, "foo", 5.0);
     QPropertyAnimation *fooAnimation = new QPropertyAnimation(object, "foo", s2);
-    s1->addTransition(new EventTransition(QEvent::User, s2))->addAnimation(fooAnimation);
+    EventTransition *trans = new EventTransition(QEvent::User, s2);
+    s1->addTransition(trans);
+    trans->addAnimation(fooAnimation);
 
     QState *s3 = new QState(&machine);
     QObject::connect(s3, SIGNAL(entered()), QCoreApplication::instance(), SLOT(quit()));
@@ -3126,7 +3128,9 @@ void tst_QStateMachine::twoAnimatedTransitions()
     QState *s4 = new QState(&machine);
     s4->assignProperty(object, "foo", 2.0);
     QPropertyAnimation *fooAnimation2 = new QPropertyAnimation(object, "foo", s4);
-    s3->addTransition(new EventTransition(QEvent::User, s4))->addAnimation(fooAnimation2);
+    trans = new EventTransition(QEvent::User, s4);
+    s3->addTransition(trans);
+    trans->addAnimation(fooAnimation2);
 
     QState *s5 = new QState(&machine);
     QObject::connect(s5, SIGNAL(entered()), QApplication::instance(), SLOT(quit()));
@@ -3161,7 +3165,9 @@ void tst_QStateMachine::playAnimationTwice()
     QState *s2 = new QState(&machine);
     s2->assignProperty(object, "foo", 5.0);
     QPropertyAnimation *fooAnimation = new QPropertyAnimation(object, "foo", s2);
-    s1->addTransition(new EventTransition(QEvent::User, s2))->addAnimation(fooAnimation);
+    EventTransition *trans = new EventTransition(QEvent::User, s2);
+    s1->addTransition(trans);
+    trans->addAnimation(fooAnimation);
 
     QState *s3 = new QState(&machine);
     QObject::connect(s3, SIGNAL(entered()), QCoreApplication::instance(), SLOT(quit()));
@@ -3169,7 +3175,9 @@ void tst_QStateMachine::playAnimationTwice()
 
     QState *s4 = new QState(&machine);
     s4->assignProperty(object, "foo", 2.0);
-    s3->addTransition(new EventTransition(QEvent::User, s4))->addAnimation(fooAnimation);
+    trans = new EventTransition(QEvent::User, s4);
+    s3->addTransition(trans);
+    trans->addAnimation(fooAnimation);
 
     QState *s5 = new QState(&machine);
     QObject::connect(s5, SIGNAL(entered()), QApplication::instance(), SLOT(quit()));
@@ -3213,14 +3221,16 @@ void tst_QStateMachine::nestedTargetStateForAnimation()
 
     QState *s2Child2 = new QState(s2);
     s2Child2->assignProperty(object, "bar", 11.0);
-    QAbstractTransition *at = s2Child->addTransition(new EventTransition(QEvent::User, s2Child2));
+    QAbstractTransition *at = new EventTransition(QEvent::User, s2Child2);
+    s2Child->addTransition(at);
 
     QPropertyAnimation *animation = new QPropertyAnimation(object, "bar", s2);
     animation->setDuration(2000);
     connect(animation, SIGNAL(finished()), &counter, SLOT(slot()));
     at->addAnimation(animation);
 
-    at = s1->addTransition(new EventTransition(QEvent::User, s2));
+    at = new EventTransition(QEvent::User, s2);
+    s1->addTransition(at);
 
     animation = new QPropertyAnimation(object, "foo", s2);
     connect(animation, SIGNAL(finished()), &counter, SLOT(slot()));
@@ -3299,7 +3309,8 @@ void tst_QStateMachine::animatedGlobalRestoreProperty()
     QState *s4 = new QState(&machine);
     QObject::connect(s4, SIGNAL(entered()), QCoreApplication::instance(), SLOT(quit()));
 
-    QAbstractTransition *at = s1->addTransition(new EventTransition(QEvent::User, s2));
+    QAbstractTransition *at = new EventTransition(QEvent::User, s2);
+    s1->addTransition(at);
     QPropertyAnimation *pa = new QPropertyAnimation(object, "foo", s2);
     connect(pa, SIGNAL(finished()), &counter, SLOT(slot()));
     at->addAnimation(pa);
@@ -3341,7 +3352,9 @@ void tst_QStateMachine::specificTargetValueOfAnimation()
 
     QPropertyAnimation *anim = new QPropertyAnimation(object, "foo");
     anim->setEndValue(10.0);
-    s1->addTransition(new EventTransition(QEvent::User, s2))->addAnimation(anim);
+    EventTransition *trans = new EventTransition(QEvent::User, s2);
+    s1->addTransition(trans);
+    trans->addAnimation(anim);
 
     QState *s3 = new QState(&machine);
     QObject::connect(s3, SIGNAL(entered()), QCoreApplication::instance(), SLOT(quit()));
@@ -3495,7 +3508,8 @@ void tst_QStateMachine::overrideDefaultAnimationWithSpecific()
     QState *s3 = new QState(&machine);
     QObject::connect(s3, SIGNAL(entered()), QCoreApplication::instance(), SLOT(quit()));
 
-    QAbstractTransition *at = s1->addTransition(new EventTransition(QEvent::User, s2));
+    QAbstractTransition *at = new EventTransition(QEvent::User, s2);
+    s1->addTransition(at);
 
     QPropertyAnimation *defaultAnimation = new QPropertyAnimation(object, "foo");
     connect(defaultAnimation, SIGNAL(stateChanged(QAbstractAnimation::State, QAbstractAnimation::State)), &counter, SLOT(slot()));