format-patch: fix two-argument special case, and make it easier to pick single commits

diff --git a/show-branch.c b/show-branch.c
index 631336cd9debb7f97b0e644c9ad51853c220aef4..d8808eefceae77f552a3a5a12c6dcc6159afbe0b 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)",