[PATCH 2/2] peel_onion(): teach $foo^{object} peeler
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Mar 31, 2013, 22:38 UTC
- Message-ID
- <7vy5d3nqik.fsf_-_@alter.siamese.dyndns.org>
- In-Reply-To
- <7vhajtpdtc.fsf@alter.siamese.dyndns.org>
A string that names an object can be suffixed with ^{type} peeler to say "I have this object name; peel it until you get this type. If you cannot do so, it is an error". v1.8.2^{commit} asks for a commit that is pointed at an annotated tag v1.8.2; v1.8.2^{tree} unwraps it further to the top-level tree object. A special suffix ^{} (i.e. no type specified) means "I do not care what it unwraps to; just peel annotated tag until you get something that is not a tag".
When you have a random user-supplied string, you can turn it to a bare 40-hex object name, and cause it to error out if such an object does not exist, with:
git rev-parse --verify "$userstring^{}"for most objects, but this does not yield the tag object name when $userstring refers to an annotated tag.
Introduce a new suffix, ^{object}, that only makes sure the given name refers to an existing object. Then
git rev-parse --verify "$userstring^{object}"becomes a way to make sure $userstring refers to an existing object.
This is necessary because the plumbing "rev-parse --verify" is only about "make sure the argument is something we can feed to get_sha1() and turn it into a raw 20-byte object name SHA-1" and is not about "make sure that 20-byte object name SHA-1 refers to an object that exists in our object store". When the given $userstring is already a 40-hex, by definition "rev-parse --verify $userstring" can turn it into a raw 20-byte object name. With "$userstring^{object}", we can make sure that the 40-hex string names an object that exists in our object store before "--verify" kicks in.
Signed-off-by: Junio C Hamano <gitster@pobox.com> --- sha1_name.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/sha1_name.c b/sha1_name.c index 45788df..85b6e75 100644 --- a/sha1_name.c +++ b/sha1_name.c @@ -594,7 +594,7 @@ struct object *peel_to_type(const char *name, int namelen, while (1) { if (!o || (!o->parsed && !parse_object(o->sha1))) return NULL; - if (o->type == expected_type) + if (expected_type == OBJ_ANY || o->type == expected_type) return o; if (o->type == OBJ_TAG) o = ((struct tag*) o)->tagged; @@ -645,6 +645,8 @@ static int peel_onion(const char *name, int len, unsigned char *sha1) expected_type = OBJ_TREE; else if (!strncmp(blob_type, sp, 4) && sp[4] == '}') expected_type = OBJ_BLOB; + else if (!prefixcmp(sp, "object}")) + expected_type = OBJ_ANY; else if (sp[0] == '}') expected_type = OBJ_NONE; else if (sp[0] == '/')
-- 1.8.2-441-g6e6f07b