Do not return a body for HEAD requests

lib/Starman/Server.pm

@@ -473,7 +473,7 @@ sub _finalize_response {
 
     if ( $protocol eq 'HTTP/1.1' ) {
         if ( !exists $headers{'content-length'} ) {
-            if ( $status !~ /^1\d\d|[23]04$/ ) {
+            if ( $status !~ /^1\d\d|[23]04$/ && $env->{REQUEST_METHOD} ne 'HEAD' ) {
                 DEBUG && warn "[$$] Using chunked transfer-encoding to send unknown length body\n";
                 push @headers, 'Transfer-Encoding: chunked';
                 $chunked = 1;

t/head_no_body.t

@@ -0,0 +1,43 @@
+use strict;
+use Test::TCP;
+use IO::Socket::INET;
+use HTTP::Request;
+use HTTP::Response;
+use Plack::Loader;
+use Test::More;
+
+$ENV{PLACK_SERVER} = 'Starman';
+
+test_tcp(
+    client => sub {
+        my $port = shift;
+
+        my $socket = IO::Socket::INET->new(
+            PeerAddr => 'localhost',
+            PeerPort => $port,
+            Proto => 'tcp'
+        ) or die "Failed to connect to server: $!";
+
+        my $request = HTTP::Request->new(
+            HEAD => '/', [ Host => 'localhost' ]
+        );
+        $request->protocol('HTTP/1.1');
+
+        $socket->send($request->as_string("\r\n"));
+
+        my $buf;
+        $socket->recv($buf, 1024);
+
+        my $res = HTTP::Response->parse($buf);
+
+        is $res->content, '';
+    },
+    server => sub {
+        my $port = shift;
+        my $server = Plack::Loader->auto(port => $port, host => '127.0.0.1');
+
+        $server->run(sub { return [ 200, [], [] ] });
+    }
+);
+
+done_testing;