httpd/async: set O_NONBLOCK correctly

While Perl tie is nice for some things, getting
IO::Handle->blocking to work transparently with it doesn't
seem possible at the moment.

Add some examples in t/spawn.t for future hackers.

Fixes: 22e51bd9da476fa9 ("qspawn: switch to ProcessPipe via popen_rd")

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/PublicInbox/HTTPD/Async.pm b/lib/PublicInbox/HTTPD/Async.pm
index bd1fd8fa..1de9501d 100644
--- a/lib/PublicInbox/HTTPD/Async.pm
+++ b/lib/PublicInbox/HTTPD/Async.pm
@@ -37,7 +37,8 @@ sub new {
                 arg => $arg, # arg for $cb
                 end_obj => $end_obj, # like END{}, can ->event_step
         }, $class;
-        IO::Handle::blocking($io, 0);
+        my $pp = tied *$io;
+        $pp->{fh}->blocking(0) // die "$io->blocking(0): $!";
         $self->SUPER::new($io, EPOLLIN | EPOLLET);
 }