Broken subtest under forkprove in version 1.301001_022 and newer

[kocoureasy]

Hello,
I found that is broken subtest run in forkprove when I use Test::More in version 1.301001_022 and newer.
This is test file as forkprove.t:

#!/bin/env perl

use strict;
use warnings;

use Test::More tests => 1;

subtest 'no compile-time warnings' => sub {
    my @warnings;
    local $SIG{'__WARN__'} = sub { push @warnings, $_[0] };

    require Test::More;;

    is_deeply(\@warnings, [], 'no warnings');
  }

I run this test script with this command forkprove -MTest::More forkprove.t

In version 1.301001_021 and oder worked properly.

Regards
Igor

[exodist]

Hmm, Test2, whcih Test::More uses under the hood has some advanced support for preload+fork harnesses. Unfortunately I am not sure how to make forkprove support them.

They are not documented, but here is a reference
https://metacpan.org/release/EXODIST/Test-Simple-1.302210/source/lib/Test2/API.pm#L215

A preloading tool should call start_preload, and then post-fork call stop_preload.

I had to add these because of a bugfix which is what broke forkprove. There were issues where if a test loaded Test::More, but did NOTHING after that, it would not fail. Which meant if your test loaded a module that resulted in exit(0) you would have a false-pass. This broke the protections of done_testing and similar. Preloading Test::More in one process, then having tests in the child processes results in the parent essentially doing the same thing, it loads Test::More, then exits without running any tests.

Unfortunately there is no good solution to letting forkprove load Test::More while also protecting against false-passes when you load it in a test and do nothing.

One option would be to have forkprove call POSIX::_exit($exit) from the parent when it is done. Or it can be intelligent and preload Test2::API and use the advanced preloading tools I mentioned above.

I do not see a solution to this that does not mean a change to forkprove, even if the solution is Test::More looking for an env-var to tell it to do the right thing.

Even if we were to go back to the pre-test2 days any solution to the 'Load Test::More, but exit doing nothing' problem would result in this issue.