Commit 0bca165f authored by Jeff King's avatar Jeff King Committed by Junio C Hamano

validate_headref: use get_oid_hex for detached HEADs

If a candidate HEAD isn't a symref, we check that it
contains a viable sha1. But in a post-sha1 world, we should
be checking whether it has any plausible object-id.

We can do that by switching to get_oid_hex().

Note that both before and after this patch, we only check
for a plausible object id at the start of the file, and then
call that good enough.  We ignore any content _after_ the
hex, so a string like:

  0123456789012345678901234567890123456789 foo

is accepted. Though we do put extra bytes like this into
some pseudorefs (e.g., FETCH_HEAD), we don't typically do so
with HEAD. We could tighten this up by using parse_oid_hex(),
like:

  if (!parse_oid_hex(buffer, &oid, &end) &&
      *end++ == '\n' && *end == '\0')
          return 0;

But we're probably better to remain on the loose side. We're
just checking here for a plausible-looking repository
directory, so heuristics are acceptable (if we really want
to be meticulous, we should use the actual ref code to parse
HEAD).
Signed-off-by: default avatarJeff King <[email protected]>
Signed-off-by: default avatarJunio C Hamano <[email protected]>
parent 7eb4b9d0
......@@ -638,7 +638,7 @@ int validate_headref(const char *path)
struct stat st;
char buffer[256];
const char *refname;
unsigned char sha1[20];
struct object_id oid;
int fd;
ssize_t len;
......@@ -679,7 +679,7 @@ int validate_headref(const char *path)
/*
* Is this a detached HEAD?
*/
if (!get_sha1_hex(buffer, sha1))
if (!get_oid_hex(buffer, &oid))
return 0;
return -1;
......
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