sha1_name: don't resolve refs when core.warnambiguousrefs is false
commit832cf74c0792a58c9c28e32a8fe5dbb694f0cce6
authorBrodie Rao <brodie@sf.io>
Tue, 7 Jan 2014 03:32:01 +0000 (6 19:32 -0800)
committerJunio C Hamano <gitster@pobox.com>
Tue, 7 Jan 2014 17:51:56 +0000 (7 09:51 -0800)
tree3b6a5b33ce61f80d935028818c65f5a160ec8921
parentc90d3dbe7db37f298e7ce858cfc4c494113f8945
sha1_name: don't resolve refs when core.warnambiguousrefs is false

When seeing a full 40-hex object name, get_sha1_basic()
unconditionally checks if the string can also be interpreted as a
refname, but the result will not be used unless warn_ambiguous_refs
is in effect.

Omitting this unnecessary ref resolution provides a substantial
performance improvement, especially when passing many hashes to a
command (like "git rev-list --stdin") and core.warnambiguousrefs is
set to false.  The check incurs 6 stat()s for every hash supplied,
which can be costly over NFS.

Signed-off-by: Brodie Rao <brodie@sf.io>
Acked-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
sha1_name.c