On 2021-03-01 at 18:15:29, Junio C Hamano wrote:
> "brian m. carlson" <sandals@crustytoothpaste.net> writes:
> 
> >   The output of 'git archive' is guaranteed to be the same across
> >   versions of git, but the archive itself is not guaranteed to be
> >   bit-for-bit identical.
> 
> I do not quite get this; your original was clearer.  What does it
> mean to "be the same across versions of git but not identical" at
> the same time?  If output from Git version 1.0 and 2.0 are guranteed
> to be the same across versions, what more is there for the readers
> to worry about the format stability?
> 
> Perhaps you meant
> 
> 	... is guaranteed to be the same for any given version of
> 	Git across ports.
> 
> or something?  It would allow kernel.org's use of "Konstantin tells
> kernel.org users to use Git version X to run 'git archive' and
> create detached signature on the output, and upload only the
> signature.  The site uses the same Git version X to run 'git
> archive' to create a tarball and the detached signature magically
> matches, as the output on two places are bit-for-bit identical".

I think what I had intended was that Git produces deterministic output,
but I don't actually think that's true across ports.  If someone uses a
different version of zlib on a different OS, the output may differ.

I'll rephrase to avoid giving a misleading impression.

> >   The output of 'git archive' has changed
> >   in the past, and most likely will in the future.
> 
> That is correct as a statement of fact.  I feel that saying it is
> either redundant and insufficient at the same time.  If we want to
> tell them "do not depend on the output being bit-for-bit identical",
> we should say it more explicitly after this sentence, I would think.

I agree we should explicitly say that.
-- 
brian m. carlson (he/him or they/them)
Houston, Texas, US