On 18 September 2013 02:32, Russ Allbery <rra@stanford.edu> wrote:
David Patte ₯ <dpatte@relativedata.com> writes:
Maybe I am misunderstanding, but doesn't this proposal, in effect, removes the ability of us documenting improved transition dates in areas outside of the active regions?
No, any zone that's turned into a link can be trivially turned back into a zone with its own rules with no user-visible impact.
On 18 September 2013 09:19, Guy Harris <guy@alum.mit.edu> wrote:
I'm saying that if we were to get rid of that transition information (if, for example, we have little confidence in it), and make some tzdb zones Links to another zone when, with the removal of the transition information, they have the same information, that does not prevent us from later putting the transition information back in (if, for example, we get more reliable information) and making those tzdb zones separate again. Removing the transition information would, obviously, mean that it would not currently be in the database, but it would *NOT* mean that we could never put it back in.
Both these comments are perfectly reasonable. A Link can, in technical terms, be converted back to a Zone if additional researched/reliable data is found. However, it is my understanding of Paul's comments that he will refuse to do so: Me: None of the above should stop existing Zone and Link entries from being expanded with researched historic data. ie. pre-1970 data for the existing set of IDs should remain in the main files... http://article.gmane.org/gmane.comp.time.tz/7171 Paul: That doesn't follow. If the main files currently have a link, and we want to turn this into a zone only because of pre-1970 data, we want to keep it a link in the main file, so that we can support existing implementations that are based on the typical current practice. http://article.gmane.org/gmane.comp.time.tz/7175 Me: Furthermore, had someone provided detailed pre-1970 data for America/Aruba a year ago, I think you would have accepted it. Yet you are arguing that now you've made it a Link you can no longer accept it. I would suggest that isn't logical or best practice. http://article.gmane.org/gmane.comp.time.tz/7178 Paul: No, we've excluded similar pre-1970 data in the past, e.g.,Europe/Zagreb. http://article.gmane.org/gmane.comp.time.tz/7181 Based on this I infer that the conversion from Zone to Link is not temporary, but permanent. There will be no way to reinsert the data into the main tzdb (it might be reinsertable into a secondary/extended/pre-1970 file, but not the main data set as currently designed). As such and from my perspective, the changes under discussion result in a permanently worse set of data for source code consumers like Java and PHP which rely on accurate data for each ID (and don't care about the Link vs Zone or zic compiled data size). My strong preference is to retain this kind of data (reverting the deletions) until there is some alternate means of representing it and a long enough period for source code data consumers to adapt their parsers (ie. at least 6 months). Stephen