RE: Millisecond precision in timestamps?

["Jason Pyeron" <jpyeron@pdinc.us>]

> -----Original Message-----
> From: Jeff King
> Sent: Tuesday, November 27, 2012 20:18
> 
> On Tue, Nov 27, 2012 at 05:07:34PM -0800, Shawn O. Pearce wrote:
> 
> > On Tue, Nov 27, 2012 at 4:26 PM, Felipe Contreras 
> > <felipe.contreras@gmail.com> wrote:
> > > On Wed, Nov 28, 2012 at 1:12 AM, Eric S. Raymond 
> <esr@thyrsus.com> wrote:
> > >> Shawn Pearce <spearce@spearce.org>:
> > >>> Well... if we added a fractional seconds to a commit, older 
> > >>> versions of Git will scream loudly and refuse to work 
> with the new 
> > >>> commit. That would create a fork of Git.
> > >>
> > >> So much for that idea, I guess.
> > >>
> > >> Unless..I don't know how git's database representations 
> work.  Are 
> > >> they version-stamped in any way?  If so, some slightly painful 
> > >> hackery would get around that problem.
> > >
> > > % git cat-file -p HEAD
> > >
> > > You'll see exactly how git stores commits. Changing anything in 
> > > there must be done carefully.
> > 
> > Apparently there is no room to change in these fields 
> without breaking 
> > compatibility with all current versions of Git. So its not 
> just done 
> > carefully... its deciding to make Git 2.0 that is not 
> compatible with 
> > any Git 1.x release.
> 
> There is room for new headers, and older versions of git will 
> ignore them. You could add a new "committer-timestamp" field 
> that elaborates on the timestamp included on the committer 
> line. Newer versions of git would respect it, and older 
> versions would fall back to using the committer timestamp.

Suggestion add a ms offset field. Ex:

jpyeron@black /projects/git/git
$ git cat-file -p HEAD
tree 1e24acfbfcc05aa57e8cb2cfe3ffe01cb100961d
parent e98fa647aa5673cc95b6e9be1fdc13c0afa2cb37
author Junio C Hamano <gitster@pobox.com> 1350495361 -0700
committer Junio C Hamano <gitster@pobox.com> 1350495402 -0700
mstimestamps author 0 committer 1234

Git 1.7.12.4

Signed-off-by: Junio C Hamano <gitster@pobox.com>


> 
> But I really wonder if anybody actually cares about adding 
> sub-second timestamp support, or if it is merely "because SVN has it".

Not because subversion has it but because date != git(precisedate) and some
automation using git in a larger enterprise workflow may assume that date
1354065991.1234 going in should be the same when queried.

-Jason



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