[RFC/largely untested/PATCH] sha1_name: interpret ~n as HEAD~n

From: Michael J Gruber <git@drmicha.warpmail.net>
Date: Apr 29, 2011, 15:53 UTC
Message-ID: <6c53916752bf79178113157291fd675ead0804c9.1304092338.git.git@drmicha.warpmail.net>

HEAD~n is often used for rebase invocations etc. Make it use the same default we use in other places, i.e. ~n == HEAD~n.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---
I haven't checked the side effects but find this super useful. Stop
me right now if this is a bad idea...

An alternative patch subject for this would have been:

sha1_name: We don't need no hg revision numbers, stupid!
---
 sha1_name.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/sha1_name.c b/sha1_name.c
index 69cd6c8..5d52eac 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -480,7 +480,10 @@ static int get_nth_ancestor(const char *name, int len,
 	struct commit *commit;
 	int ret;
 
-	ret = get_sha1_1(name, len, sha1);
+	if (len)
+		ret = get_sha1_1(name, len, sha1);
+	else
+		ret = get_sha1("HEAD", sha1);
 	if (ret)
 		return ret;
 	commit = lookup_commit_reference(sha1);

-- 
1.7.5.250.g4493b