Selecting the first or last possible date can result in error upon reopening the dialog

[chabad360]

Bug Description

The Picker reuses the time portion of a given DateTime if a use doesn't select a time. This can cause it to return an invalid DateTime if the user selected the earliest or latest possible date. Upon attempting to reopen the picker, the picker will crash, complaining that the _selectedDateTime is before or after the specified minimum or maximum DateTime.

Reproduction Steps

1. Set DateTime.now().subtract(Duration(days: 7)) as the minimumDateTime.
2. Set DateTime.now().subtract(Duration(minutes: 10)) as the initialDateTime.
3. Select the earliest possible day (7 days ago) in the picker.
4. Reopen the picker.
5. Error.

Supposed solution

Picker should either disallow selecting an invalid DateTime or constrain the selection to be within the minimum and maximum.

[philip-soft]

Hello! I couldn't reproduce this case. Did I do everything right?

  Future<DateTime?> onCalendarWidgetTap(BuildContext context) async {
    final RenderBox? renderBox = context.findRenderObject() as RenderBox?;

    return showCupertinoCalendarPicker(
      context,
      widgetRenderBox: renderBox,
      maximumDateTime: _maximumDateTime,
      minimumDateTime: DateTime.now().subtract(const Duration(days: 7)),
      initialDateTime: DateTime.now().subtract(const Duration(minutes: 10)),
      mode: CupertinoCalendarMode.dateTime,
      timeLabel: 'Ends',
      onDateTimeChanged: _onDateTimeChanged,
    );
  }

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2025-07-20.at.07.28.21.mp4

[chabad360]

No, when you re-show the picker, the initialDateTime is not the same as the _selectedDateTime because it's set dynamically. If you use the CupertinoCalendarPickerButton the initialDateTime is ignored once the user uses it.