Re: Creating remote branch called HEAD corrupts remote clones

[Erik Faye-Lund <kusmabite@gmail.com>]

On Wed, Apr 27, 2011 at 1:29 PM, Stephen Kelly <steveire@gmail.com> wrote:
> On Wed, Apr 27, 2011 at 11:48 AM, Felipe Contreras
> <felipe.contreras@gmail.com> wrote:
>> No problems here:
>
> I had another go.
>
> mkdir remote
> cd remote/
> git init --bare
> cd ../
> git clone remote/ alice
> cd alice/
> echo test >> file
> git add file
> git commit -am w
> git push origin master
> echo test >> file
> git commit -am w
> git branch HEAD

I'll stop you here. You reproduce the issue a lot simpler:

git init foo &&
cd foo &&
echo "foo" > bar &&
git add bar &&
git commit -m. &&
git branch HEAD &&
gitk

No need to involve remote branches. While remote branches makes the
issue worse, because you can get in a situation where gitk doesn't
when someone else made a nasty branch, and you fetched it.

The real problem is that "git rev-parse HEAD" outputs "warning:
refname 'HEAD' is ambiguous." to stderr (even if stderr is a non-tty),
and gitk does not like that.

This can be fixed by either doing "git -c core.warnambiguousrefs=0
rev-parse HEAD", which strikes me as ugly, or by making sure that we
don't issue this warning when not attached to a tty:

diff --git a/sha1_name.c b/sha1_name.c
index faea58d..c7e855e 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -391,7 +391,7 @@ static int get_sha1_basic(const char *str, int
len, unsigned char *sha1)
 	if (!refs_found)
 		return -1;

-	if (warn_ambiguous_refs && refs_found > 1)
+	if (warn_ambiguous_refs && refs_found > 1 && isatty(2))
 		warning(warn_msg, len, str);

 	if (reflog_len) {