QLineEdit: ignore key release events

Amends 55fe46fd58. Before that change,
key release events were ignored as the QLineEdit::event reimplementation
continued to call QWidget::event, and as QLineEdit didn't override
keyReleaseEvent, the default implementation in QWidget got called to
ignore the event.

Restore that behavior by explicitly calling the QWidget implementation
after updating QLineEdit-specific states, and add a test case.

Fixes: QTBUG-114654
Pick-to: 6.5 6.6
Change-Id: Ic8aa35a1c915b446aece47aaf03ef5cf1884b936
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

src/widgets/widgets/qlineedit.cpp

@@ -1747,12 +1747,13 @@ void QLineEdit::keyPressEvent(QKeyEvent *event)
 /*!
     \reimp
 */
-void QLineEdit::keyReleaseEvent(QKeyEvent *)
+void QLineEdit::keyReleaseEvent(QKeyEvent *e)
 {
     Q_D(QLineEdit);
     if (!isReadOnly())
         d->handleSoftwareInputPanel();
     d->control->updateCursorBlinking();
+    QWidget::keyReleaseEvent(e);
 }
 
 /*!

tests/auto/widgets/widgets/qlineedit/tst_qlineedit.cpp

@@ -292,6 +292,8 @@ private slots:
     void QTBUG_60319_setInputMaskCheckImSurroundingText();
     void testQuickSelectionWithMouse();
     void inputRejected();
+    void keyReleasePropagates();
+
 protected slots:
     void editingFinished();
 
@@ -5143,5 +5145,43 @@ void tst_QLineEdit::inputRejected()
     QCOMPARE(spyInputRejected.size(), 2);
 }
 
+void tst_QLineEdit::keyReleasePropagates()
+{
+    struct Dialog : QWidget
+    {
+        QLineEdit *lineEdit;
+        int releasedKey = {};
+
+        Dialog()
+        {
+            lineEdit = new QLineEdit;
+            QHBoxLayout *hbox = new QHBoxLayout;
+
+            hbox->addWidget(lineEdit);
+            setLayout(hbox);
+        }
+
+    protected:
+        void keyReleaseEvent(QKeyEvent *e)
+        {
+            releasedKey = e->key();
+        }
+    } dialog;
+
+    dialog.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&dialog));
+
+    QTest::keyPress(dialog.lineEdit, Qt::Key_A);
+    QTest::keyRelease(dialog.lineEdit, Qt::Key_A);
+
+    QCOMPARE(dialog.releasedKey, Qt::Key_A);
+
+    QTest::keyPress(dialog.lineEdit, Qt::Key_Alt);
+    QTest::keyRelease(dialog.lineEdit, Qt::Key_Alt);
+
+    QCOMPARE(dialog.releasedKey, Qt::Key_Alt);
+}
+
+
 QTEST_MAIN(tst_QLineEdit)
 #include "tst_qlineedit.moc"