From 0cd34a0c39bf443f1ea6f6868ac6fbc0fc2c9e6d Mon Sep 17 00:00:00 2001
From: Erik Verbruggen <erik.verbruggen@digia.com>
Date: Fri, 19 Jun 2015 11:11:31 +0200
Subject: StateMachine: remove initial state for parallel states.

A parallel state cannot have an initial state, as all children of the
parallel state will be entered. Setting such an initial state on a
QState marked as ParallelStates would already produce a warning and
ignore the initial state. Now any initial state that has been set before
changing the child-mode to ParallelStates will also produce a warning
and remove the previously set initial state.

Change-Id: Ie5fcd44b03516744f785f2d1880bf806918c44d4
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
---
 src/corelib/statemachine/qstate.cpp                |  8 ++++++
 .../corelib/statemachine/qstate/tst_qstate.cpp     | 31 ++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/src/corelib/statemachine/qstate.cpp b/src/corelib/statemachine/qstate.cpp
index 5abbbfd9ad..3b84230cb2 100644
--- a/src/corelib/statemachine/qstate.cpp
+++ b/src/corelib/statemachine/qstate.cpp
@@ -518,6 +518,14 @@ QState::ChildMode QState::childMode() const
 void QState::setChildMode(ChildMode mode)
 {
     Q_D(QState);
+
+    if (mode == QState::ParallelStates && d->initialState) {
+        qWarning("QState::setChildMode: setting the child-mode of state %p to "
+                 "parallel removes the initial state", this);
+        d->initialState = Q_NULLPTR;
+        emit initialStateChanged(QState::QPrivateSignal());
+    }
+
     if (d->childMode != mode) {
         d->childMode = mode;
         emit childModeChanged(QState::QPrivateSignal());
diff --git a/tests/auto/corelib/statemachine/qstate/tst_qstate.cpp b/tests/auto/corelib/statemachine/qstate/tst_qstate.cpp
index ac3374b6a3..c64d55671a 100644
--- a/tests/auto/corelib/statemachine/qstate/tst_qstate.cpp
+++ b/tests/auto/corelib/statemachine/qstate/tst_qstate.cpp
@@ -47,6 +47,7 @@ private slots:
     void historyInitialState();
     void transitions();
     void privateSignals();
+    void parallelStateAndInitialState();
 };
 
 class TestClass: public QObject
@@ -344,5 +345,35 @@ void tst_QState::privateSignals()
 
 }
 
+void tst_QState::parallelStateAndInitialState()
+{
+    QStateMachine machine;
+
+    { // setting an initial state on a parallel state:
+        QState a(QState::ParallelStates, &machine);
+        QState b(&a);
+        QVERIFY(!a.initialState());
+        const QString warning
+            = QString::asprintf("QState::setInitialState: ignoring attempt to set initial state of parallel state group %p", &a);
+        QTest::ignoreMessage(QtWarningMsg, qPrintable(warning));
+        a.setInitialState(&b); // should produce a warning and do nothing.
+        QVERIFY(!a.initialState());
+    }
+
+    { // setting the child-mode from ExclusiveStates to ParallelStates should remove the initial state:
+        QState a(QState::ExclusiveStates, &machine);
+        QState b(&a);
+        a.setInitialState(&b);
+        QCOMPARE(a.initialState(), &b);
+        const QString warning
+            = QString::asprintf("QState::setChildMode: setting the child-mode of state %p to "
+                                "parallel removes the initial state", &a);
+        QTest::ignoreMessage(QtWarningMsg, qPrintable(warning));
+        a.setChildMode(QState::ParallelStates); // should produce a warning and remove the initial state
+        QVERIFY(!a.initialState());
+        QCOMPARE(a.childMode(), QState::ParallelStates);
+    }
+}
+
 QTEST_MAIN(tst_QState)
 #include "tst_qstate.moc"
-- 
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