On 2018-01-18 19:39:50 (-0500), Tom Lane wrote:
Zefram <zefram@fysh.org> writes:
There was indeed a significant chance of the negative SAVE value breaking alternate zic implementations, and now that that's turned out to be the case that's good cause to postpone this correction, or at least the expressing of it in this natural manner. The tzdb does have unusually high stability requirements. But that's not a reason to keep the database forever inaccurate.
I'm not sure that it's "inaccurate". The question is more about what is the meaning of tm_isdst = 1. It's clear from this discussion that an awful lot of code believes it means "local time is advanced now compared to what it is when tm_isdst = 0". Arguing that it should reflect a legalistic definition of DST, rather than an operational definition, is just an argument; it's not conclusive.
FWIW, I share the opinion that this change was misguided.
I'd go with "premature" rather than "misguided". Given the number of things this break, I would suggest backing the change out for now but pointing out in NEWS that it will come back say one year from now. Replace the actual change by a comment that the current data is inaccurate pending software being fixed. Philip -- Philip Paeps Senior Reality Engineer Ministry of Information