We do not like "HEAD" as a new branch name

[git.git] / sha1_name.c

diff --git a/sha1_name.c b/sha1_name.c
index cc320d3..bf8f0f0 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -203,6 +203,31 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
        return NULL;
 }
 
+static int ambiguous_path(const char *path, int len)
+{
+       int slash = 1;
+       int cnt;
+
+       for (cnt = 0; cnt < len; cnt++) {
+               switch (*path++) {
+               case '\0':
+                       break;
+               case '/':
+                       if (slash)
+                               break;
+                       slash = 1;
+                       continue;
+               case '.':
+                       continue;
+               default:
+                       slash = 0;
+                       continue;
+               }
+               return slash;
+       }
+       return slash;
+}
+
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 {
        static const char *prefix[] = {
@@ -213,17 +238,47 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
                NULL
        };
        const char **p;
+       int found = 0;
 
        if (len == 40 && !get_sha1_hex(str, sha1))
                return 0;
 
+       /* Accept only unambiguous ref paths. */
+       if (ambiguous_path(str, len))
+               return -1;
+
        for (p = prefix; *p; p++) {
                char *pathname = git_path("%s/%.*s", *p, len, str);
-               if (!read_ref(pathname, sha1))
-                       return 0;
-       }
 
-       return -1;
+               if (!read_ref(pathname, sha1)) {
+                       /* Must be unique; i.e. when heads/foo and
+                        * tags/foo are both present, reject "foo".
+                        */
+                       if (1 < found++)
+                               return -1;
+               }
+
+               /* We want to allow .git/description file and
+                * "description" branch to exist at the same time.
+                * "git-rev-parse description" should silently skip
+                * .git/description file as a candidate for
+                * get_sha1().  However, having garbage file anywhere
+                * under refs/ is not OK, and we would not have caught
+                * ambiguous heads and tags with the above test.
+                */
+               else if (**p && !access(pathname, F_OK)) {
+                       /* Garbage exists under .git/refs */
+                       return error("garbage ref found '%s'", pathname);
+               }
+       }
+       switch (found) {
+       case 0:
+               return -1;
+       case 1:
+               return 0;
+       default:
+               return error("ambiguous refname '%.*s'", len, str);
+       }
 }
 
 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
@@ -322,7 +377,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
        if (!o)
                return -1;
        if (!type_string) {
-               o = deref_tag(o);
+               o = deref_tag(o, name, sp - name - 2);
                if (!o || (!o->parsed && !parse_object(o->sha1)))
                        return -1;
                memcpy(sha1, o->sha1, 20);