Resolve ambiguity for permanent timezone changes #155
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`Biz::Time` already passes true as the `dst` parameter to `local_to_utc` to avoid the ambiguity of converting a local time that occurred twice due to daylight savings time. However if a local time occurs twice due to a permanent timezone change, the `dst` parameter doesn't help. `local_to_utc` can be given a block to handle this case: https://github.com/tzinfo/tzinfo/blob/v2.0.6/lib/tzinfo/timezone.rb#L613-L619 > The `dst` parameter will not be able to resolve an ambiguity resulting > from the clocks being set back without changing from daylight savings > time to standard time. In this case, if a block is specified, it will > be called to resolve the ambiguity. The block must take a single > parameter - an `Array` of {TimezonePeriod}s that need to be resolved. > The block can select and return a single {TimezonePeriod} or return > `nil` or an empty `Array` to cause an {AmbiguousTime} exception to be > raised.
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Biz::Timealready passes true as thedstparameter tolocal_to_utcto avoid the ambiguity of converting a local time that occurred twice due to daylight savings time.However if a local time occurs twice due to a permanent timezone change, the
dstparameter doesn't help.local_to_utccan be given a block to handle this case:https://github.com/tzinfo/tzinfo/blob/v2.0.6/lib/tzinfo/timezone.rb#L613-L619
I encountered this problem due to a recent timezone change in Kazakhstan:
https://mm.icann.org/pipermail/tz-announce/2024-February/000081.html
I used an older example in the test so that it doesn't require the latest tz database.