First of all many thanks for the responses.
And yes refs/heads/foo-g<hash> will be interpreted by "git checkout" as "git-describe" output, if there is no such branch. My current solution for the moment is to extract the commit-sha1 from the output of "git for-each-ref" and fail if there is no exact match otherwise git checkout will anyway do what I want, because it finds the branch.
Regards
Heiko
________________________________________
Von: Duy Nguyen [pclouds@xxxxxxxxx]
Gesendet: Dienstag, 25. Juni 2019 13:43
An: Junio C Hamano
Cc: Kyle Meyer; Boettger, Heiko; git@xxxxxxxxxxxxxxx
Betreff: Re: specifying revision - how to enforce matching a tag/branch-name or revision only
On Fri, Jun 21, 2019 at 10:16 PM Junio C Hamano <gitster@xxxxxxxxx> wrote:
>
> Kyle Meyer <kyle@xxxxxxxxxx> writes:
>
> >> git rev-parse "${BRANCH_NAME}" || git rev-parse "refs/remotes/${UPSTREAM}/${BRANCH_NAME}"
> >>
> >> Unfortunately somebody used the branch name "add-gcc10" and `git rev-parse` which didn't exist on one repository. However `git rev-parse`
> >> also supports to parse the `git-describe` format which resulted in checkout a commit starting with "cc10".
I wonder if something like refs/heads/foo-g<hash> could trip the
parser and mistake it as a `git-describe` output. Staring at
get_describe_name() alone the answer might be an unfortunate "yes".
But maybe something will kick in earlier and reject it.
> >
> > Can't you prepend "refs/heads/" to BRANCH_NAME to disambiguate?
>
> Yes, that is the kosher way for most commands.
Some commands always prepend refs/heads/ to the <branch> argument you
give it if I remember correctly. Or I think I accidentally made
refs/heads/refs/heads/something once with some command (then hell
ensued). If true, prepending refs/heads/ is not really foolproof.
> It gets a bit tricky for "checkout <branch-or-committish>" that
> changes its behaviour (a local branch is checked out and the next
> commit extends it, other committishes like tags and remote-tracking
> branch tips are checked out on a detached HEAD), and has special
> rules for a "${BRANCH_NAME}" that is both the name of a local branch
> and something else.
I think "git checkout --no-guess --no-detach <branch>" should only
accept a branch (i.e. ref: refs/heads/<branch>). Dropping --no-detach
should allow any ref, which interprets refs/heads/foo as an absolute
ref, not as refs/heads/refs/heads/foo.
> Hopefully (Duy Cc'ed) "git switch" would improve the situation.
"git switch" has slightly saner defaults, but with --guess being
default to be friendlier to interactive usage, it's still not that
much friendlier to scripts, unfortunately.
--
Duy
