[PATCH 5/6] checkout-index: disallow "--no-stage" option

[Jeff King <peff@peff.net>]

We do not really expect people to use "--no-stage", but if
they do, git currently segfaults. We could instead have it
undo the effects of a previous "--stage", but this gets
tricky around the "to_tempfile" flag. We cannot simply reset
it to 0, because we don't know if it was set by a previous
"--stage=all" or an explicit "--temp" option.

We could solve this by setting a flag and resolving
to_tempfile later, but it's not worth the effort. Nobody
actually wants to use "--no-stage"; we are just trying to
fix a potential segfault here.

While we're in the area adding a translated string, let's
mark the other possible error message in this function as
translatable.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/checkout-index.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/builtin/checkout-index.c b/builtin/checkout-index.c
index f8179a7..7a9b561 100644
--- a/builtin/checkout-index.c
+++ b/builtin/checkout-index.c
@@ -133,6 +133,8 @@ static struct lock_file lock_file;
 static int option_parse_stage(const struct option *opt,
 			      const char *arg, int unset)
 {
+	if (unset)
+		return error(_("--stage cannot be negated"));
 	if (!strcmp(arg, "all")) {
 		to_tempfile = 1;
 		checkout_stage = CHECKOUT_ALL;
@@ -141,7 +143,7 @@ static int option_parse_stage(const struct option *opt,
 		if ('1' <= ch && ch <= '3')
 			checkout_stage = arg[0] - '0';
 		else
-			die("stage should be between 1 and 3 or all");
+			die(_("stage should be between 1 and 3 or all"));
 	}
 	return 0;
 }
-- 
2.7.0.489.g6faad84