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Test-More / test-more

Test2, Test::More, Test::Simple and Test::Builder Perl modules for writing tests
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Unclear error message #960

Open xenu opened 5 years ago

xenu commented 5 years ago 
use Test2::V0;

use threads;

threads->create(sub {
    ok 1, 'foo';
})->join;

The above script fails with Test2 must be fully loaded before you start a new thread! at a.pl line 7 thread 1.. It is not clear at all what "fully loaded" does mean, and this concept doesn't seem to exist in Test2 documentation.

It stops crashing when I either add use Test2::IPC; or call ok(1) before creating a new thread. Perhaps the error message should recommend doing that?

exodist commented 5 years ago

That is indeed confusing. Documentation (and the error message) should be corrected.

I will explain it here, but yeah docs and such also need to be updated.

Test2 has a lot of internal state that it delays setting until the last possible moment. These are things like "Are we using IPC", "What renderer is going to be used", "Do we need Test::Builder compatibility stuff in place", etc. Test2 is not considered fully loaded until these things all happen.

When does this normally happen? It usually happens when the very first event is generated (plan, assertion, note, diag, etc). When IPC is loaded there is an INIT block that forces it after BEGIN time as well to make threading/forking easier: https://github.com/Test-More/test-more/blob/master/lib/Test2/IPC.pm#L28

It might make sense to always have this init block, I am not sure.