I'm finding something strange with a site I'm building in SS. I have a Date field in the $db static on a DataObject. To the user, it appears as a CalendarDateField managed via the ModelAdmin. With the nature of the DataObject (the dates relate to people's birth dates and death dates), there will be lots of dates before 1970. When I enter a date before 1970 and save the DataObject, it gets set to 1/1/1970. No bueno.
Interestingly, when I edit the field manually in the database via phpMyAdmin, I can set the date to any of the acceptable MySQL date range values (i.e. 1000-01-01 at the earliest). Also of interest is that when I reload the DataObject in the admin after editing the DB directly, the field will show up with the pre-1970 date I enter. Upon saving, it reverts back to 1970 whether I edit it or not. So, this means the switcheroo is happening in the save routine, but I haven't found it yet.
I've been digging for a few minutes and thought I ought to post here about it to see if anyone else had encountered this as a issue. If I figure it out, I'll post back with the solution.
My workarounds were generally forcing whatever was inputting dates to use date('Y-m-d') before passing it back for saving. On forms it was pre-parsing the return and transforming it. For the Datepicker it was hacking the JS, per the above post I referenced.
onBeforeWrite() is also an option. None are an elegant solution. Unfortunately its all hacks right now. I think I've seen several open bugs that are prioritized for 2.4, but no code has been checked in or patches provided yet.