send-email: be more lenient and just catch obvious mistakes.

This cleans up the pattern matching subroutine by introducing
two variables to hold regexp to approximately match local-part
and domain in the e-mail address.  It is meant to catch obvious
mistakes with a cheap check.

The patch also moves "scalar" to force Email::Valid->address()
to work in !wantarray environment to extract_valid_address;
earlier it was in the caller of the subroutine, which was way
too error prone.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-send-email.perl

@@ -312,16 +312,18 @@ sub expand_aliases {
 
 sub extract_valid_address {
 	my $address = shift;
+	my $local_part_regexp = '[^<>"\s@]+';
+	my $domain_regexp = '[^.<>"\s@]+\.[^<>"\s@]+';
 
 	# check for a local address:
-	return $address if ($address =~ /^([\w\-.]+)$/);
+	return $address if ($address =~ /^($local_part_regexp)$/);
 
 	if ($have_email_valid) {
-		return Email::Valid->address($address);
+		return scalar Email::Valid->address($address);
 	} else {
 		# less robust/correct than the monster regexp in Email::Valid,
 		# but still does a 99% job, and one less dependency
-		$address =~ /([\w\-.]+@[\w\-.]+)/;
+		$address =~ /($local_part_regexp\@$domain_regexp)/;
 		return $1;
 	}
 }
@@ -384,7 +386,7 @@ sub send_message
 		defined $pid or die $!;
 		if (!$pid) {
 			exec($smtp_server,'-i',
-			     map { scalar extract_valid_address($_) }
+			     map { extract_valid_address($_) }
 			     @recipients) or die $!;
 		}
 		print $sm "$header\n$message";