If you're on 1.4 you have serious issues when moving between timezones (in this case the winter/summer time switch) see https://code.google.com/p/pharo/issues/detail?id=5919 and http://forum.world.st/Bug-in-DateAndTime-td2293749.html the problem is, that the reference point was not defined in a fixed time-zone but rather relative, which breaks under certain conditions!! On 2012-10-30, at 22:20, Paul DeBruicker <pdebruic@gmail.com> wrote:
I have an attribute "date" in a domain object. Last week, I created some objects with this attribute. Today I created objects again with the same date value in this attribute. When comparing the dates (=), the result is false.
Reason is, that in germany, we had a switch from Central European Summer Time (CEST) (Sommerzeit) to Daylight Saving Time (DST) this weekend.
Date has an attribute "start" which has an instance of DateAndTime. This DateAndTime object has another value depending on the CEST/DST
2012-10-02T00:00:00+
01:00
(DST) 2012-10-02T00:00:00+
02:00
(CEST)
When I create two Dates with same date, I expect that = evaluates to true, independent from the CEST/DST. But Date (Timespan) uses / = comparand ^ self class = comparand class and: [
self start = comparand start
Sabine Knöfel wrote * * * * * *
and: [ self duration = comparand duration ]]
/
What do you recommend? Create my own compare method? Did I miss something?
Localized dates and times are awful to mess with because the timing of the daylight savings transitions are political and vary from place to place and year to year.
This is good advice from Tom Rushworth on comparing dates: http://forum.world.st/Should-Dates-be-Timezone-specific-tp3647678p3649107.ht...
Also on Squeaksource the TimeZoneDatabase and Chronos packages have mechanisims for keeping up to date about when offsets should be changed in the image.
For me, my image's internal timezone is set to UTC. I use Chronos and store everything as UTC, use UTC values for every calculation, then convert it back to the local time only on display to a user.
-- View this message in context: http://forum.world.st/Problem-with-Date-comparing-summer-time-CEST-tp4653354... Sent from the Pharo Smalltalk mailing list archive at Nabble.com.