[squeak-dev] DateAndTimeLeapTest>>testAsSeconds is broken

Chris Muller asqueaker at gmail.com
Sun Dec 4 00:05:05 UTC 2016

On Sat, Dec 3, 2016 at 5:12 PM, David T. Lewis <lewis at mail.msen.com> wrote:
> On Sat, Dec 03, 2016 at 04:06:10PM -0600, Chris Muller wrote:
>> Hmm..  Magma used DateAndTime>>#asSeconds to store the integral
>> representation of the timestamp of its commit-log records..  however,
>> as the commit-log records are rarely consumed at all, I think this
>> should be okay.
> Think about what would happen if someone was actively using a Magma
> database during a "fall back" daylight savings time transition period.

Unless I'm missing something, that example does not relate to this.
The timestamps in the logs would merely reflect the local time, which
would retrace itself by one hour.  A similar retracement would still
occur even after we fixed this, right?  The only impact I can think of
is if someone wanted to restore the database to a prior point in time
*within* that retraced period; in which their time specification would
be ambiguous as it naturally is in the real world anyway in a fallback
DST change..

>> Does anyone else have any major impacts?  Dave, you mentioned objects
>> in the snapshot.bin files, needing a "format" conversion, what is
>> that?
> That is a separate topic. In UTCDateAndTime I changed the instance variables
> in DateAndTime, which requires considering what to do with "old format"
> instances that may be stored in a snapshot.bin and need to be materialized
> while processing the Monticello update stream that I prepared for UTCDateAndTime.
> I added the necessary support recently, but I will need to rebuild the update
> stream is there is interest in using it.

I am still interested, I just have to take the time and care to convert.

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