push: use remote.$name.push as a refmap

Since f2690487 (fetch: opportunistically update tracking refs,
2013-05-11), we stopped taking a non-storing refspec given on the
command line of "git fetch" literally, and instead started mapping
it via remote.$name.fetch refspecs.  This allows

    $ git fetch origin master

from the 'origin' repository, which is configured with

    [remote "origin"]
        fetch = +refs/heads/*:refs/remotes/origin/*

to update refs/remotes/origin/master with the result, as if the
command line were

    $ git fetch origin +master:refs/remotes/origin/master

to reduce surprises and improve usability.  Before that change, a
refspec on the command line without a colon was only to fetch the
history and leave the result in FETCH_HEAD, without updating the
remote-tracking branches.

When you are simulating a fetch from you by your mothership with a
push by you into your mothership, instead of having:

    [remote "satellite"]
        fetch = +refs/heads/*:refs/remotes/satellite/*

on the mothership repository and running:

    mothership$ git fetch satellite

you would have:

    [remote "mothership"]
        push = +refs/heads/*:refs/remotes/satellite/*

on your satellite machine, and run:

    satellite$ git push mothership

Because we so far did not make the corresponding change to the push
side, this command:

    satellite$ git push mothership master

does _not_ allow you on the satellite to only push 'master' out but
still to the usual destination (i.e. refs/remotes/satellite/master).

Implement the logic to map an unqualified refspec given on the
command line via the remote.$name.push refspec.  This will bring a
bit more symmetry between "fetch" and "push".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 38 insertions, 2 deletions

diff --git a/builtin/push.c b/builtin/push.c
index 76e4400c4a..857f76d85a 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -35,9 +35,38 @@ static void add_refspec(const char *ref)
 	refspec[refspec_nr-1] = ref;
 }
 
-static void set_refspecs(const char **refs, int nr)
+static const char *map_refspec(const char *ref,
+			       struct remote *remote, struct ref *local_refs)
 {
+	struct ref *matched = NULL;
+
+	/* Does "ref" uniquely name our ref? */
+	if (count_refspec_match(ref, local_refs, &matched) != 1)
+		return ref;
+
+	if (remote->push) {
+		struct refspec query;
+		memset(&query, 0, sizeof(struct refspec));
+		query.src = matched->name;
+		if (!query_refspecs(remote->push, remote->push_refspec_nr, &query) &&
+		    query.dst) {
+			struct strbuf buf = STRBUF_INIT;
+			strbuf_addf(&buf, "%s%s:%s",
+				    query.force ? "+" : "",
+				    query.src, query.dst);
+			return strbuf_detach(&buf, NULL);
+		}
+	}
+
+	return ref;
+}
+
+static void set_refspecs(const char **refs, int nr, const char *repo)
+{
+	struct remote *remote = NULL;
+	struct ref *local_refs = NULL;
 	int i;
+
 	for (i = 0; i < nr; i++) {
 		const char *ref = refs[i];
 		if (!strcmp("tag", ref)) {
@@ -56,6 +85,13 @@ static void set_refspecs(const char **refs, int nr)
 				die(_("--delete only accepts plain target ref names"));
 			strbuf_addf(&delref, ":%s", ref);
 			ref = strbuf_detach(&delref, NULL);
+		} else if (!strchr(ref, ':')) {
+			if (!remote) {
+				/* lazily grab remote and local_refs */
+				remote = remote_get(repo);
+				local_refs = get_local_heads();
+			}
+			ref = map_refspec(ref, remote, local_refs);
 		}
 		add_refspec(ref);
 	}
@@ -487,7 +523,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 
 	if (argc > 0) {
 		repo = argv[0];
-		set_refspecs(argv + 1, argc - 1);
+		set_refspecs(argv + 1, argc - 1, repo);
 	}
 
 	rc = do_push(repo, flags);