[PATCH] filter-branch: when dwim'ing a ref, only allow heads and tags

Previously, we matched all refs that had /$ref in them. And tried to verify the result as a ref. If more than one match was found, the result was not a ref, though.

So only allow tags and heads to be dwim'ed. If both a tag and a head with that name exist, it will be ignored again.

Caught by Johannes Sixt.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---

	On Tue, 24 Jul 2007, Johannes Sixt wrote:

	> Johannes Schindelin wrote:
	> > +# These refs should be updated if their heads were rewritten
	> > +
	> > +git rev-parse --revs-only --symbolic "$@" |
	> > +while read ref
	> > +do
	> > +       # normalize ref
	> > +       case "$ref" in
	> > +       HEAD)
	> > +               ref="$(git symbolic-ref "$ref")"
	> > +       ;;
	> > +       refs/*)
	> > +       ;;
	> > +       *)
	> > +               ref="$(git for-each-ref --format='%(refname)' |
	> > +                       grep /"$ref")"
	> > +       esac
	> > +
	> > +       git check-ref-format "$ref" && echo "$ref"
	> > +done > "$tempdir"/heads
	> 
	> This does not work as I'd expected it: I can't successfully say:
	> 
	>    git-filter-branch master
	> 
	> It tells me:
	> 
	>    Which ref do you want to rewrite?

	I tried that, and happily got the same.  The explanation: more 
	than one ref matched "/master".  My pattern was extremely borked.

	Thanks.

 git-filter-branch.sh     |    2 +-
 t/t7003-filter-branch.sh |    5 +++++
 2 files changed, 6 insertions(+), 1 deletions(-)