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 <[email protected]> wrote: > Sabine Knöfel 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 > * >> 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.html > > 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-tp4653354p4653383.html > Sent from the Pharo Smalltalk mailing list archive at Nabble.com. >
