Emit the highlighted signal if the model changes.

The bug is that the connection to emit that signal can be made
obsolete if the connection is made too early and the model is replaced.
In the bug report, the connection is made by calling view() early (thereby
causing the creation of a view and a QItemSelectionModel which operates on
the built-in QItemSelectionModel, and then connecting to that
QItemSelectionModel), and then when QComboBox::setModel() is called later
the built-in view creates a new QItemSelectionModel for it. The bug was
that that new QItemSelectionModel is not connected to. This patch fixes that
bug.

Task-number: QTBUG-4454
Change-Id: Ibbdb8731f16ab071008b4a19dc2cc7ae03cebc84
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
index ba3cf13271..eaf44d93cd 100644
--- a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
+++ b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
@@ -158,6 +158,7 @@ private slots:
     void task_QTBUG_1071_changingFocusEmitsActivated();
     void maxVisibleItems();
     void task_QTBUG_10491_currentIndexAndModelColumn();
+    void highlightedSignal();
 
 protected slots:
     void onEditTextChanged( const QString &newString );
@@ -2565,5 +2566,33 @@ void tst_QComboBox::task_QTBUG_10491_currentIndexAndModelColumn()
     QCOMPARE(QModelIndex(d->currentIndex), model.index(2, comboBox.modelColumn()));
 }
 
+void tst_QComboBox::highlightedSignal()
+{
+    QComboBox comboBox;
+
+    QSignalSpy spy(&comboBox, SIGNAL(highlighted(int)));
+    QVERIFY(spy.isValid());
+
+    // Calling view() before setting the model causes the creation
+    // of a QComboBoxPrivateContainer containing an actual view, and connecting to
+    // the selectionModel to generate the highlighted signal. When setModel is called
+    // further down, that selectionModel is obsolete. We test that the highlighted
+    // signal is emitted anyway as the bug fix. (QTBUG-4454)
+    comboBox.view();
+    QItemSelectionModel *initialItemSelectionModel = comboBox.view()->selectionModel();
+
+
+    QStandardItemModel model;
+    for (int i = 0; i < 5; i++)
+        model.appendRow(new QStandardItem(QString::number(i)));
+    comboBox.setModel(&model);
+
+    comboBox.view()->selectionModel()->setCurrentIndex(model.index(0, 0), QItemSelectionModel::Current);
+
+    QVERIFY(initialItemSelectionModel != comboBox.view()->selectionModel());
+
+    QCOMPARE(spy.size(), 1);
+}
+
 QTEST_MAIN(tst_QComboBox)
 #include "tst_qcombobox.moc"