[PATCH 3/3] branch: die when setting branch as own upstream

[Brian Gesiak <modocache@gmail.com>]

Branch set as own upstream using one of the following commands returns
immediately with an exit code of 0:

- `git branch --set-upstream-to foo refs/heads/foo`
- `git branch --force --track foo foo`

Since neither of these actions currently set the upstream, an exit code
of 0 is misleading. Instead, exit with a status code indicating failure
by using the die function.

Signed-off-by: Brian Gesiak <modocache@gmail.com>
---
 branch.c          | 9 ++-------
 t/t3200-branch.sh | 6 +++---
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/branch.c b/branch.c
index e163f3c..9bac8b5 100644
--- a/branch.c
+++ b/branch.c
@@ -54,13 +54,8 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
 	struct strbuf key = STRBUF_INIT;
 	int rebasing = should_setup_rebase(origin);
 
-	if (shortname
-	    && !strcmp(local, shortname)
-	    && !origin) {
-		warning(_("Not setting branch %s as its own upstream."),
-			local);
-		return;
-	}
+	if (shortname && !strcmp(local, shortname) && !origin)
+		die(_("Not setting branch %s as its own upstream."), local);
 
 	strbuf_addf(&key, "branch.%s.remote", local);
 	git_config_set(key.buf, origin ? origin : ".");
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 6164126..3ac493f 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -507,10 +507,10 @@ EOF
 	test_cmp expected actual
 '
 
-test_expect_success '--set-upstream-to shows warning if used to set branch as own upstream' '
-	git branch --set-upstream-to refs/heads/my13 my13 2>actual &&
+test_expect_success '--set-upstream-to fails if used to set branch as own upstream' '
+	test_must_fail git branch --set-upstream-to refs/heads/my13 my13 2>actual &&
 	cat >expected <<EOF &&
-warning: Not setting branch my13 as its own upstream.
+fatal: Not setting branch my13 as its own upstream.
 EOF
 	test_i18ncmp expected actual
 '
-- 
1.8.3.4 (Apple Git-47)