Apparent race condition with `done` and ultra-short Supply.interval

[p6rt]

Migrated from rt.perl.org#128991 (status was 'resolved')

Searchable as RT128991$

[p6rt]

From @zoffixznet

This code produces the following exception with Rakudo dd5c28. If interval is changed to a larger
value, the issue does not occur​:

react {
  whenever Supply.interval(.001) {
  done if $++ > 1000;
  }
}
sleep 1;

Unhandled exception in code scheduled on thread 4
Access denied to keep/break this Promise; already vowed
  in any at /home/zoffix/.rakudobrew/moar-nom/install/share/perl6/runtime/CORE.setting.moarvm line 1
  in sub THROW-NIL at /home/zoffix/.rakudobrew/moar-nom/install/share/perl6/runtime/CORE.setting.moarvm line 1
  in block at test.p6 line 4

[p6rt]

From @jnthn

On Fri, 19 Aug 2016 10​:06​:01 -0700, cpan@​zoffix.com wrote​:

This code produces the following exception with Rakudo dd5c28. If
interval is changed to a larger
value, the issue does not occur​:

react {
whenever Supply.interval(.001) {
done if $++ > 1000;
}
}
sleep 1;

Unhandled exception in code scheduled on thread 4
Access denied to keep/break this Promise; already vowed
in any at /home/zoffix/.rakudobrew/moar-
nom/install/share/perl6/runtime/CORE.setting.moarvm line 1
in sub THROW-NIL at /home/zoffix/.rakudobrew/moar-
nom/install/share/perl6/runtime/CORE.setting.moarvm line 1
in block at test.p6 line 4

Fixed (the fix should prevent a whole class of similar problems rather than just this specific instance). Tests in S17-supply/syntax.t.

/jnthn

[p6rt]

The RT System itself - Status changed from 'new' to 'open'

[p6rt]

@jnthn - Status changed from 'open' to 'resolved'