[PATCH 5/5] cache: make oidcpy always copy GIT_MAX_RAWSZ bytes
Martin Ă…gren
Junio C Hamano
brian m. carlson
See Also
Prev Ref 1
2019-01-10 04:25:51 UTC
There are some situations in which we want to store an object ID into
struct object_id without the_hash_algo necessarily being set correctly.
One such case is when cloning a repository, where we must read refs from
the remote side without having a repository from which to read the
preferred algorithm.

In this cases, we may have the_hash_algo set to SHA-1, which is the
default, but read refs into struct object_id that are SHA-256. When
copying these values, we will want to copy them completely, not just the
first 20 bytes. Consequently, make sure that oidcpy copies the maximum
number of bytes at all times, regardless of the setting of

Since oidcpy and hashcpy are no longer functionally identical, remove
the Cocinelle object_id transformations that convert from one into the

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
 cache.h                            |  2 +-
 contrib/coccinelle/object_id.cocci | 30 ------------------------------
 2 files changed, 1 insertion(+), 31 deletions(-)

diff --git a/cache.h b/cache.h
index ca36b44ee0..8b8c6a1a2a 100644
--- a/cache.h
+++ b/cache.h
@@ -1072,7 +1072,7 @@ static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
 static inline void oidcpy(struct object_id *dst, const struct object_id *src)
-	hashcpy(dst->hash, src->hash);
+	memcpy(dst->hash, src->hash, GIT_MAX_RAWSZ);
 static inline struct object_id *oiddup(const struct object_id *src)
diff --git a/contrib/coccinelle/object_id.cocci b/contrib/coccinelle/object_id.cocci
index 6a7cf3e02d..3e536a9834 100644
--- a/contrib/coccinelle/object_id.cocci
+++ b/contrib/coccinelle/object_id.cocci
@@ -86,36 +86,6 @@ struct object_id OID;
 - hashcmp(OID.hash, OIDPTR->hash)
 + oidcmp(&OID, OIDPTR)
-struct object_id OID1, OID2;
-- hashcpy(OID1.hash, OID2.hash)
-+ oidcpy(&OID1, &OID2)
-identifier f != oidcpy;
-struct object_id *OIDPTR1;
-struct object_id *OIDPTR2;
-  f(...) {<...
-- hashcpy(OIDPTR1->hash, OIDPTR2->hash)
-+ oidcpy(OIDPTR1, OIDPTR2)
-  ...>}
-struct object_id *OIDPTR;
-struct object_id OID;
-- hashcpy(OIDPTR->hash, OID.hash)
-+ oidcpy(OIDPTR, &OID)
-struct object_id *OIDPTR;
-struct object_id OID;
-- hashcpy(OID.hash, OIDPTR->hash)
-+ oidcpy(&OID, OIDPTR)
 struct object_id *OIDPTR1;
 struct object_id *OIDPTR2;