validate_headref: tighten ref-matching to just branches

When we are trying to determine whether a directory contains
a git repository, one of the tests we do is to check whether
HEAD is either a symlink or a symref into the "refs/"
hierarchy, or a detached HEAD.

We can tighten this a little more, though: a non-detached
HEAD should always point to a branch (since checking out
anything else should result in detachment), so it is safe to
check for "refs/heads/".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/path.c b/path.c
index a074aea..108d9e9 100644 (file)
--- a/path.c
+++ b/path.c
@@ -154,7 +154,7 @@ int validate_headref(const char *path)
        /* Make sure it is a "refs/.." symlink */
        if (S_ISLNK(st.st_mode)) {
                len = readlink(path, buffer, sizeof(buffer)-1);
-               if (len >= 5 && !memcmp("refs/", buffer, 5))
+               if (len >= 11 && !memcmp("refs/heads/", buffer, 11))
                        return 0;
                return -1;
        }
@@ -178,7 +178,7 @@ int validate_headref(const char *path)
                len -= 4;
                while (len && isspace(*buf))
                        buf++, len--;
-               if (len >= 5 && !memcmp("refs/", buf, 5))
+               if (len >= 11 && !memcmp("refs/heads/", buf, 11))
                        return 0;
        }