[PATCH 13/13] eml: drop trailing blank line on missing epilogue

[Eric Wong <e@yhbt.net>]

This improves Email::MIME compatibility when running
xt/cmp-msgview.t on some GPG-signed messages.

Its usefulness is dubious in the long term and this patch
may be reverted down the line.
---
 lib/PublicInbox/Eml.pm | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/Eml.pm b/lib/PublicInbox/Eml.pm
index 1adaff04..4508bd84 100644
--- a/lib/PublicInbox/Eml.pm
+++ b/lib/PublicInbox/Eml.pm
@@ -131,8 +131,12 @@ sub mp_descend ($$) {
 	# Cut at the the first epilogue, not subsequent ones.
 	# *sigh* just the regexp match alone seems to bump RSS by
 	# length($$bdy) on a ~30M string:
-	$$bdy =~ /((?:\r?\n)?^--$bnd--[ \t]*\r?$)/gsm and
+	my $epilogue_missing;
+	if ($$bdy =~ /((?:\r?\n)?^--$bnd--[ \t]*\r?$)/gsm) {
 		substr($$bdy, pos($$bdy) - length($1)) = '';
+	} else {
+		$epilogue_missing = 1;
+	}
 
 	# *Sigh* split() doesn't work in-place and return CoW strings
 	# because Perl wants to "\0"-terminate strings.  So split()
@@ -150,6 +154,10 @@ sub mp_descend ($$) {
 
 	if (@parts) { # the usual path if we got this far:
 		undef $bdy; # release memory ASAP if $nr > 0
+
+		# compatibility with Email::MIME
+		$parts[-1] =~ s/\n\r?\n\z/\n/s if $epilogue_missing;
+
 		@parts = grep /[^ \t\r\n]/s, @parts; # ignore empty parts
 
 		# Keep "From: someone..." from preamble in old,