refs outside refs/{heads,tags} match less strongly.

This changes the refname matching logic used to decide which ref
is updated with git-send-pack.  We used to error out when
pushing 'master' when the other end has both 'master' branch and
a tracking branch 'remotes/$name/master' but with this, 'master'
matches only 'refs/heads/master' when both and no other 'master'
exist.

Pushing 'foo' when both heads/foo and tags/foo exist at the
remote end is still considered an error and you would need to
disambiguate between them by being more explicit.

When neither heads/foo nor tags/foo exists at the remote,
pushing 'foo' when there is only remotes/origin/foo is not
ambiguous, while it still is ambiguous when there are more than
one such weaker match (remotes/origin/foo and remotes/alt/foo,
for example).

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

diff --git a/connect.c b/connect.c
index c55a20a..b9666cc 100644 (file)
--- a/connect.c
+++ b/connect.c
@@ -174,21 +174,58 @@ static int count_refspec_match(const char *pattern,
                               struct ref *refs,
                               struct ref **matched_ref)
 {
-       int match;
        int patlen = strlen(pattern);
+       struct ref *matched_weak = NULL;
+       struct ref *matched = NULL;
+       int weak_match = 0;
+       int match = 0;
 
-       for (match = 0; refs; refs = refs->next) {
+       for (weak_match = match = 0; refs; refs = refs->next) {
                char *name = refs->name;
                int namelen = strlen(name);
+               int weak_match;
+
                if (namelen < patlen ||
                    memcmp(name + namelen - patlen, pattern, patlen))
                        continue;
                if (namelen != patlen && name[namelen - patlen - 1] != '/')
                        continue;
-               match++;
-               *matched_ref = refs;
+
+               /* A match is "weak" if it is with refs outside
+                * heads or tags, and did not specify the pattern
+                * in full (e.g. "refs/remotes/origin/master") or at
+                * least from the toplevel (e.g. "remotes/origin/master");
+                * otherwise "git push $URL master" would result in
+                * ambiguity between remotes/origin/master and heads/master
+                * at the remote site.
+                */
+               if (namelen != patlen &&
+                   patlen != namelen - 5 &&
+                   strncmp(name, "refs/heads/", 11) &&
+                   strncmp(name, "refs/tags/", 10)) {
+                       /* We want to catch the case where only weak
+                        * matches are found and there are multiple
+                        * matches, and where more than one strong
+                        * matches are found, as ambiguous.  One
+                        * strong match with zero or more weak matches
+                        * are acceptable as a unique match.
+                        */
+                       matched_weak = refs;
+                       weak_match++;
+               }
+               else {
+                       matched = refs;
+                       match++;
+               }
+       }
+       if (!matched) {
+               *matched_ref = matched_weak;
+               return weak_match;
+       }
+       else {
+               *matched_ref = matched;
+               return match;
        }
-       return match;
 }
 
 static void link_dst_tail(struct ref *ref, struct ref ***tail)