Correctly update QComboBox appearance on editable change

The updateDelegate() function checks isEditable() which in
turn checks if d->lineEdit != 0, so we need to make the
call after the lineEdit has actually been set/unset, otherwise
the change to the delegate will not come until the next time
you update the delegate.

[ChangeLog][QComboBox] Fixed updating appearance of popup menu
when changing the editable state of the combo box.

Change-Id: Ib32f36cabd53c2c30d6256484a1eae131419960a
Task-number: QTBUG-33537
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
index f6928f0b35..ac32ee4968 100644
--- a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
+++ b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
@@ -160,6 +160,7 @@ private slots:
     void task_QTBUG_31146_popupCompletion();
     void keyboardSelection();
     void setCustomModelAndView();
+    void updateDelegateOnEditableChange();
 };
 
 class MyAbstractItemDelegate : public QAbstractItemDelegate
@@ -3049,5 +3050,32 @@ void tst_QComboBox::keyboardSelection()
     QCOMPARE(comboBox.currentText(), list.at(1));
 }
 
+void tst_QComboBox::updateDelegateOnEditableChange()
+{
+
+    QComboBox box;
+    box.addItem(QStringLiteral("Foo"));
+    box.addItem(QStringLiteral("Bar"));
+    box.setEditable(false);
+
+    QComboBoxPrivate *d = static_cast<QComboBoxPrivate *>(QComboBoxPrivate::get(&box));
+
+    {
+        bool menuDelegateBefore = qobject_cast<QComboMenuDelegate *>(box.itemDelegate()) != 0;
+        d->updateDelegate();
+        bool menuDelegateAfter = qobject_cast<QComboMenuDelegate *>(box.itemDelegate()) != 0;
+        QCOMPARE(menuDelegateAfter, menuDelegateBefore);
+    }
+
+    box.setEditable(true);
+
+    {
+        bool menuDelegateBefore = qobject_cast<QComboMenuDelegate *>(box.itemDelegate()) != 0;
+        d->updateDelegate();
+        bool menuDelegateAfter = qobject_cast<QComboMenuDelegate *>(box.itemDelegate()) != 0;
+        QCOMPARE(menuDelegateAfter, menuDelegateBefore);
+    }
+}
+
 QTEST_MAIN(tst_QComboBox)
 #include "tst_qcombobox.moc"