remote: use remote_is_configured() for add and renametg/git-remote

Both remote add and remote rename use a slightly different hand-rolled
check if the remote exits.  The hand-rolled check may have some subtle
cases in which it might fail to detect when a remote already exists.
One such case was fixed in fb86e32 ("git remote: allow adding remotes
agreeing with url.<...>.insteadOf").  Another case is when a remote is
configured as follows:

  [remote "foo"]
    vcs = bar

If we try to run `git remote add foo bar` with the above remote
configuration, git segfaults.  This change fixes it.

In addition, git remote rename $existing foo with the configuration for
foo as above silently succeeds, even though foo already exists,
modifying its configuration.  With this patch it fails with "remote foo
already exists".

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index f1d073f1ba..94079a0e63 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -157,6 +157,21 @@ test_expect_success 'rename errors out early when deleting non-existent branch'
 	)
 '
 
+test_expect_success 'add existing foreign_vcs remote' '
+	test_config remote.foo.vcs bar &&
+	echo "fatal: remote foo already exists." >expect &&
+	test_must_fail git remote add foo bar 2>actual &&
+	test_i18ncmp expect actual
+'
+
+test_expect_success 'add existing foreign_vcs remote' '
+	test_config remote.foo.vcs bar &&
+	test_config remote.bar.vcs bar &&
+	echo "fatal: remote bar already exists." >expect &&
+	test_must_fail git remote rename foo bar 2>actual &&
+	test_i18ncmp expect actual
+'
+
 cat >test/expect <<EOF
 * remote origin
   Fetch URL: $(pwd)/one