Subject: Re: [PATCH 06/18] version-gen: remove redundant check

From: Felipe Contreras <[email-masked]>
Date: Fri, 14 Apr 2023 13:32:43 -0600

Todd Zullinger wrote:
> Felipe Contreras wrote:
> > Todd Zullinger wrote:
> >> Felipe Contreras wrote:
> >>> If we are not in a git repository `git describe` will fail anyway.
> >> 
> >> The parent directory may be a git repository though.  The
> >> current code ensures that we're running `git describe` in
> >> the proper repository.
> > 
> > How exactly does it do that?
> > 
> > The current code expects the cwd to be the git repo, run it in any other
> > directory and it will generate GIT-VERSION-FILE in that directory, which is
> > clearly not intended.
> 
> Whether it's fool proof isn't really my point.  It did
> attempt to check that .git was a file or directory.  Not
> checking at all isn't necessarily an improvement, was my
> concern.
> 
> >> If we drop this, aren't we breaking things for someone
> >> building a git tarball which is in a subdirectory of a git
> >> repository?
> > 
> > How exactly would this hypothetical person build such a tarball?
> > 
> >   git init /tmp/foo
> >   mkdir -p /tmp/foo/bar
> >   cd /tmp/foo/bar
> >   make -C ~/dev/git dist
> 
> If I have a git repo, say ~/fedora/git which contains the
> fedora packaging (spec file, etc.) and extract a git archive
> in this directory, the describe will now pick up the data
> from the parent git directory, won't it?
> 
>     $ git -C ~/fedora clone https://src.fedoraproject.org/rpms/git.git
>     $ cd ~/fedora/git
>     $ git -C ~/upstream/git archive --format=tar --prefix=git/ HEAD | tar xf -
>     $ cd git
>     $ make GIT-VERSION-GEN
>     $ cat GIT-VERSION-FILE 
>     GIT_VERSION = 

I don't think this is a realistic use-case, but supposing it is, what would be
the desired outcome in this case?

 GIT_VERSION = 2.40.GIT

?

> The version file in the tarballs prevents this from
> happening in the most common case, but it still feels like
> this is loosening things a little more than it should.

If we care about this, the same behavior can be achieved with GIT_CEILING_DIRECTORIES:

 GIT_CEILING_DIRECTORIES=$(cd .. && pwd) git describe ...

-- 
Felipe Contreras