Alright! This was fixed. Bisectable points at the merge of “better-sched” branch, which happen right after 2017.09 release. See https://github.com/rakudo/rakudo/commit/61a77e60a7d936415503d8916fcc7546569e9135
Zoffix++ found some tests: https://github.com/perl6/roast/commit/ae3eea8a8b43d9c6b1be6b0f825f696df346a457 However, these tests are not enough to resolve this ticket. We'd need a stress test that does it in a loop several times, just like it is described in the OP. In any case, this is no longer ANNOYING and is simply TESTNEEDED. On 2017-07-17 21:34:25, alex.jakime...@gmail.com wrote: > Code: > > sub get-output() { > my $proc = Proc::Async.new: ‘echo’, ‘test’; > react { > #whenever $proc.stdout { } # ←↙ these work > #whenever $proc.stderr { } # > whenever $proc { } # ← this doesn't > whenever $proc.start { } > } > say $++; > } > > loop { get-output } > > > > > The result depends on your luck. Sometimes it gets stuck on the second > execution, sometimes it manages to do it over 20 times and then gets > stuck. > > According to this it is supposed to work: > https://irclog.perlgeek.de/perl6-dev/2017-07-12#i_14862898 > > I don't know if there's any trap I'm getting into, or if it's just a > bug. Anyway, I hope a ticket won't hurt.