[SQUASH] msg_part_text: discover text in application/octet-stream

[Eric Wong <e@80x24.org>]

This simplifies the check and ensures returned text is Perl "utf8"
text (that is, Perl's internal "utf8" and not the strict "UTF-8".

diff --git a/lib/PublicInbox/MsgIter.pm b/lib/PublicInbox/MsgIter.pm
index e2819523..9c6581cc 100644
--- a/lib/PublicInbox/MsgIter.pm
+++ b/lib/PublicInbox/MsgIter.pm
@@ -90,12 +90,8 @@ sub msg_part_text ($$) {
 		# Try to see if it's printable text that we can index
 		# and display:
 		$s = $part->body;
-		if ($s =~ /[^\p{XPosixPrint}\s]/s) {
-			utf8::decode($s);
-			$s =~ /[^\p{XPosixPrint}\s]/s ? undef($s) : undef($err);
-		} else {
-			undef($err);
-		}
+		utf8::decode($s);
+		undef($s =~ /[^\p{XPosixPrint}\s]/s ? $s : $err);
 	}
 	($s, $err);
 }
diff --git a/t/msg_iter.t b/t/msg_iter.t
index 6c52eec8..ae3594da 100644
--- a/t/msg_iter.t
+++ b/t/msg_iter.t
@@ -121,6 +121,7 @@ EOM
 		push @parts, $s;
 	});
 	$expect =~ s/\n/\r\n/sg;
+	utf8::decode($expect); # aka "bytes2str"
 	is_deeply(\@parts, [ "blah\r\n", $expect ],
 		'fallback to application/octet-stream as UTF-8 text');