git-remote rename: migrate from remotes/ and branches/

Remote definition that came from $GIT_DIR/remotes/nick and
$GIT_DIR/branches/nick are migrated to [remotes "nick"] section in the
configuration file.

Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin-remote.c b/builtin-remote.c
index 1ca6cdb..3af1876 100644
--- a/builtin-remote.c
+++ b/builtin-remote.c
@@ -359,6 +359,38 @@
 	return 0;
 }
 
+static int migrate_file(struct remote *remote)
+{
+	struct strbuf buf = STRBUF_INIT;
+	int i;
+	char *path = NULL;
+
+	strbuf_addf(&buf, "remote.%s.url", remote->name);
+	for (i = 0; i < remote->url_nr; i++)
+		if (git_config_set_multivar(buf.buf, remote->url[i], "^$", 0))
+			return error("Could not append '%s' to '%s'",
+					remote->url[i], buf.buf);
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "remote.%s.push", remote->name);
+	for (i = 0; i < remote->push_refspec_nr; i++)
+		if (git_config_set_multivar(buf.buf, remote->push_refspec[i], "^$", 0))
+			return error("Could not append '%s' to '%s'",
+					remote->push_refspec[i], buf.buf);
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "remote.%s.fetch", remote->name);
+	for (i = 0; i < remote->fetch_refspec_nr; i++)
+		if (git_config_set_multivar(buf.buf, remote->fetch_refspec[i], "^$", 0))
+			return error("Could not append '%s' to '%s'",
+					remote->fetch_refspec[i], buf.buf);
+	if (remote->origin == REMOTE_REMOTES)
+		path = git_path("remotes/%s", remote->name);
+	else if (remote->origin == REMOTE_BRANCHES)
+		path = git_path("branches/%s", remote->name);
+	if (path && unlink(path))
+		warning("failed to remove '%s'", path);
+	return 0;
+}
+
 static int mv(int argc, const char **argv)
 {
 	struct option options[] = {
@@ -381,6 +413,9 @@
 	if (!oldremote)
 		die("No such remote: %s", rename.old);
 
+	if (!strcmp(rename.old, rename.new) && oldremote->origin != REMOTE_CONFIG)
+		return migrate_file(oldremote);
+
 	newremote = remote_get(rename.new);
 	if (newremote && (newremote->url_nr > 1 || newremote->fetch_refspec_nr))
 		die("remote %s already exists.", rename.new);