[tz] Issues with pre-1970 information in TZDB
eggert at cs.ucla.edu
Thu Sep 23 16:47:09 UTC 2021
On 9/22/21 11:31 AM, Brooks Harris via tz wrote:
> Indeed the changes would have significant consequences to my current (in
> development) tzdb parser which reads the source files directly with no
> modifications to accumulate all time zones that have existed.
If the goal is to accumulate all timezones that have ever existed in
tzdb, the parser should read 'backzone', as 'backzone' has for some time
been the repository for entries that were formerly Zones but are now
Links in the default database.
If the parser reads 'backzone', you shouldn't notice effects due to the
recent alike-since-1970 changes. Otherwise the parser should be changed
to read 'backzone', regardless of whether the recent alike-since-1970
changes are present.
Even 'backzone' won't suffice to achieve the goal I mentioned, as I
vaguely recall some deleted Zones never made it to backzone way back
when. I don't recall the details, unfortunately. You can get most of the
details by looking at the Git history, I expect, but it'd be a bit of a
job. If you find out anything from that search, please let us know, as I
expect these old deleted Zones should be put into 'backzone' though this
is low priority.
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