Make sure heads/foo and tags/foo do not confuse things.

When both heads/foo and tags/foo exist, get_sha1_basic("foo")
picked up the tag without complaining, which is quite confusing.
Make sure we require unambiguous form, "heads/foo" or "tags/foo"
in such cases.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/sha1_name.c b/sha1_name.c
index be1755a..faac158 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -236,6 +236,7 @@ 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;
@@ -246,10 +247,20 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 
        for (p = prefix; *p; p++) {
                char *pathname = git_path("%s/%.*s", *p, len, str);
-               if (!read_ref(pathname, sha1))
-                       return 0;
+               if (!read_ref(pathname, sha1)) {
+                       /* Must be unique; i.e. when heads/foo and
+                        * tags/foo are both present, reject "foo".
+                        * Note that read_ref() eventually calls
+                        * get_sha1_hex() which can smudge initial
+                        * part of the buffer even if what is read
+                        * is found to be invalid halfway.
+                        */
+                       if (1 < found++)
+                               return -1;
+               }
        }
-
+       if (found == 1)
+               return 0;
        return -1;
 }
 

diff --git a/show-branch.c b/show-branch.c
index 631336c..d8808ee 100644 (file)
--- a/show-branch.c
+++ b/show-branch.c
@@ -313,9 +313,16 @@ static int append_ref(const char *refname, const unsigned char *sha1)
 
 static int append_head_ref(const char *refname, const unsigned char *sha1)
 {
-       if (strncmp(refname, "refs/heads/", 11))
+       unsigned char tmp[20];
+       int ofs = 11;
+       if (strncmp(refname, "refs/heads/", ofs))
                return 0;
-       return append_ref(refname + 11, sha1);
+       /* If both heads/foo and tags/foo exists, get_sha1 would
+        * get confused.
+        */
+       if (get_sha1(refname + ofs, tmp) || memcmp(tmp, sha1, 20))
+               ofs = 5;
+       return append_ref(refname + ofs, sha1);
 }
 
 static int append_tag_ref(const char *refname, const unsigned char *sha1)
@@ -470,7 +477,7 @@ int main(int ac, char **av)
                if (MAX_REVS <= num_rev)
                        die("cannot handle more than %d revs.", MAX_REVS);
                if (get_sha1(ref_name[num_rev], revkey))
-                       usage(show_branch_usage);
+                       die("'%s' is not a valid ref.\n", ref_name[num_rev]);
                commit = lookup_commit_reference(revkey);
                if (!commit)
                        die("cannot find commit %s (%s)",