remote.c: return upstream name from stat_tracking_info

After calling stat_tracking_info, callers often want to
print the name of the upstream branch (in addition to the
tracking count). To do this, they have to access
branch->merge->dst[0] themselves. This is not wrong, as the
return value from stat_tracking_info tells us whether we
have an upstream branch or not. But it is a bit leaky, as we
make an assumption about how it calculated the upstream
name.

Instead, let's add an out-parameter that lets the caller
know the upstream name we found.

As a bonus, we can get rid of the unusual tri-state return
from the function. We no longer need to use it to
differentiate between "no tracking config" and "tracking ref
does not exist" (since you can check the upstream_name for
that), so we can just use the usual 0/-1 convention for
success/error.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 11 deletions

diff --git a/builtin/branch.c b/builtin/branch.c
index b7202b3..e4d184d 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -425,25 +425,19 @@ static void fill_tracking_info(struct strbuf *stat, const char *branch_name,
 	int ours, theirs;
 	char *ref = NULL;
 	struct branch *branch = branch_get(branch_name);
+	const char *upstream;
 	struct strbuf fancy = STRBUF_INIT;
 	int upstream_is_gone = 0;
 	int added_decoration = 1;
 
-	switch (stat_tracking_info(branch, &ours, &theirs)) {
-	case 0:
-		/* no base */
-		return;
-	case -1:
-		/* with "gone" base */
+	if (stat_tracking_info(branch, &ours, &theirs, &upstream) < 0) {
+		if (!upstream)
+			return;
 		upstream_is_gone = 1;
-		break;
-	default:
-		/* with base */
-		break;
 	}
 
 	if (show_upstream_ref) {
-		ref = shorten_unambiguous_ref(branch->merge[0]->dst, 0);
+		ref = shorten_unambiguous_ref(upstream, 0);
 		if (want_color(branch_use_color))
 			strbuf_addf(&fancy, "%s%s%s",
 					branch_get_color(BRANCH_COLOR_UPSTREAM),