Setting a timeSpec on QDateTimeEdit breaks the edit when only time is shown

Because of the time zone change we get an "overflow" in the min and max time.
For example min 00:00:00 becomes 01:00:00 and max 23:59:59 becomes 00:59:59
which is an invalid time span and the displayed time gets fixed to the newly
set min/max value.
Autotest included.

Task-number: QTBUG-12384
Reviewed-by: Gabriel

2 files changed, 31 insertions, 0 deletions

diff --git a/src/gui/widgets/qdatetimeedit.cpp b/src/gui/widgets/qdatetimeedit.cpp
index 61ae21e332..3284389692 100644
--- a/src/gui/widgets/qdatetimeedit.cpp
+++ b/src/gui/widgets/qdatetimeedit.cpp
@@ -890,7 +890,13 @@ void QDateTimeEdit::setDisplayFormat(const QString &format)
         const bool dateShown = (d->sections & DateSections_Mask);
         Q_ASSERT(dateShown || timeShown);
         if (timeShown && !dateShown) {
+            QTime time = d->value.toTime();
             setDateRange(d->value.toDate(), d->value.toDate());
+            if (d->minimum.toTime() >= d->maximum.toTime()) {
+                setTimeRange(QDATETIMEEDIT_TIME_MIN, QDATETIMEEDIT_TIME_MAX);
+                // if the time range became invalid during the adjustment, the time would have been reset
+                setTime(time);
+            }
         } else if (dateShown && !timeShown) {
             setTimeRange(QDATETIMEEDIT_TIME_MIN, QDATETIMEEDIT_TIME_MAX);
             d->value = QDateTime(d->value.toDate(), QTime(), d->spec);
@@ -1654,6 +1660,15 @@ void QDateTimeEditPrivate::updateTimeSpec()
     minimum = minimum.toDateTime().toTimeSpec(spec);
     maximum = maximum.toDateTime().toTimeSpec(spec);
     value = value.toDateTime().toTimeSpec(spec);
+
+    // time zone changes can lead to 00:00:00 becomes 01:00:00 and 23:59:59 becomes 00:59:59 (invalid range)
+    const bool dateShown = (sections & QDateTimeEdit::DateSections_Mask);
+    if (!dateShown) {
+        if (minimum.toTime() >= maximum.toTime()){
+            minimum = QDateTime(value.toDate(), QDATETIMEEDIT_TIME_MIN, spec);
+            maximum = QDateTime(value.toDate(), QDATETIMEEDIT_TIME_MAX, spec);
+        }
+    }
 }
 
 void QDateTimeEditPrivate::updateEdit()
diff --git a/tests/auto/qdatetimeedit/tst_qdatetimeedit.cpp b/tests/auto/qdatetimeedit/tst_qdatetimeedit.cpp
index ff2cdca963..5a50f3f156 100644
--- a/tests/auto/qdatetimeedit/tst_qdatetimeedit.cpp
+++ b/tests/auto/qdatetimeedit/tst_qdatetimeedit.cpp
@@ -273,6 +273,9 @@ private slots:
 
     void task196924();
     void focusNextPrevChild();
+
+    void taskQTBUG_12384_timeSpecShowTimeOnly();
+
 private:
     EditorDateEdit* testWidget;
     QWidget *testFocusWidget;
@@ -3420,7 +3423,20 @@ void tst_QDateTimeEdit::focusNextPrevChild()
     QCOMPARE(edit.currentSection(), QDateTimeEdit::MonthSection);
 }
 
+void tst_QDateTimeEdit::taskQTBUG_12384_timeSpecShowTimeOnly()
+{
+    QDateTime time = QDateTime::fromString("20100723 04:02:40", "yyyyMMdd hh:mm:ss");
+    time.setTimeSpec(Qt::UTC);
+
+    EditorDateEdit edit;
+    edit.setDisplayFormat("hh:mm:ss");
+    edit.setTimeSpec(Qt::UTC);
+    edit.setDateTime(time);
 
+    QCOMPARE(edit.minimumTime(), QTime(0, 0, 0, 0));
+    QCOMPARE(edit.maximumTime(), QTime(23, 59, 59, 999));
+    QCOMPARE(edit.time(), time.time());
+}
 
 QTEST_MAIN(tst_QDateTimeEdit)
 #include "tst_qdatetimeedit.moc"