Re: Creating remote branch called HEAD corrupts remote clones

On Wed, Apr 27, 2011 at 1:29 PM, Stephen Kelly [off-list ref] wrote:

On Wed, Apr 27, 2011 at 11:48 AM, Felipe Contreras
[off-list ref] wrote:

quoted

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) {