[tz] Version in zoneinfo files?

[Guy Harris]

On Oct 25, 2015, at 10:55 AM, Paul G <paul at ganssle.io> wrote:

> I'm not suggesting that it be impossible to create a weird result when asking for the version, just that there's a standard place for the version to go, and preferably the standard default gives you something that you expected.

I.e., something that works most of the time is sufficient?

So what exactly is the intended use of this version field?

> As it is now, you're virtually guaranteed to have a lot of incompatibility because there's nothing you can point to that says, "This is the canonical way to store version information about zoneinfo files", and no standard has emerged on how to do this as is.
> 
> On 10/25/2015 01:51 PM, Guy Harris wrote:
>> 
>> On Oct 25, 2015, at 10:37 AM, Paul G <paul at ganssle.io> wrote:
>> 
>>> On 10/25/2015 01:35 PM, Guy Harris wrote:
>>> 
>>>> So where would zic get the version information to put into the binary files?
>>> 
>>> My understanding is that it's the VERSION= line of the Makefile in the tzdata tarballs.
>> 
>> I.e., you're proposing that the value of the VERSION value in the Makefile be passed as an argument to zic, and zic would put the value of that argument into a field in the files?
>> 
>> So, if the goal is to provide a "reliable way to get the version information in a cross-platform way", what would ensure that this field be set properly, for some value of "properly", everywhere that binary tzdata files are generated?
>> 
>> I.e., what is to guarantee that
>> 
>> 	1) nobody downstream change VERSION if they aren't changing the zic files from what's distributed
>> 
>> and
>> 
>> 	2) people change it "properly" if the files don't correspond to a particular version of files that were distributed (e.g., if some downstream supplier takes 2015q and adds some changes mentioned on the list to it before 2015r comes out with those changes plus other changes, they should call the resulting files something other than "2015q" or "2015r")?
>> 
>