send-email: fix missing error message regression

Fix a regression with the "the editor exited uncleanly, aborting
everything" error message going missing after my
d21616c0394 (git-send-email: refactor duplicate $? checks into a
function, 2021-04-06).

I introduced a $msg variable, but did not actually use it. This caused
us to miss the optional error message supplied by the "do_edit"
codepath. Fix that, and add tests to check that this works.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/git-send-email.perl b/git-send-email.perl
index 175da07d94..170f42fe21 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -219,8 +219,18 @@ sub system_or_msg {
 	my $exit_code = $? >> 8;
 	return unless $signalled or $exit_code;
 
+	my @sprintf_args = ($args->[0], $exit_code);
+	if (defined $msg) {
+		# Quiet the 'redundant' warning category, except we
+		# need to support down to Perl 5.8, so we can't do a
+		# "no warnings 'redundant'", since that category was
+		# introduced in perl 5.22, and asking for it will die
+		# on older perls.
+		no warnings;
+		return sprintf($msg, @sprintf_args);
+	}
 	return sprintf(__("fatal: command '%s' died with exit code %d"),
-		       $args->[0], $exit_code);
+		       @sprintf_args);
 }
 
 sub system_or_die {