send-email: validate patches before sending anything

We try to catch errors early so that we don't end up sending
half of a broken patch series. Right now the only validation
is checking that line-lengths are under the SMTP-mandated
limit of 998.

The validation parsing is very crude (it just checks each
line length without understanding the mailbox format) but
should work fine for this simple check.

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

1 files changed, 17 insertions, 0 deletions

diff --git a/git-send-email.perl b/git-send-email.perl
index 7a86977ef1..4e62c3f0e7 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -332,6 +332,11 @@ for my $f (@ARGV) {
 	}
 }
 
+foreach my $f (@files) {
+	my $error = validate_patch($f);
+	$error and die "fatal: $f: $error\nwarning: no patches were sent\n";
+}
+
 if (@files) {
 	unless ($quiet) {
 		print $_,"\n" for (@files);
@@ -837,3 +842,15 @@ sub unique_email_list(@) {
 	}
 	return @emails;
 }
+
+sub validate_patch {
+	my $fn = shift;
+	open(my $fh, '<', $fn)
+		or die "unable to open $fn: $!\n";
+	while (my $line = <$fh>) {
+		if (length($line) > 998) {
+			return "$.: patch contains a line longer than 998 characters";
+		}
+	}
+	return undef;
+}