Non-repeatable test failures in Github cron job

[rbt]

Starting about 3 days ago a different MySQL test, using subtests, fails with a message like the below. Rerunning it by hand seems to work okay. The version of MySQL and Raku changes from run to run.

I suspect the cronjob is scheduled during a busy time on the github servers and something is happening to the connection which isn't throwing a nicely caught error.

t/24-mysql-types.rakutest ............ All 5 subtests passed
...
 t/24-mysql-types.rakutest  (Wstat: 11 Tests: 0 Failed: 0)
Non-zero wait status: 11
  Parse errors: Bad plan.  You planned 5 tests but ran 0.

[rbt]

Types again today on 2020.12

[rbt]

Interesting. I don't recall seeing the "corrupted double-linked list" message before.

I also have no idea where it came from. Feels Java'ish and I don't see that message in Rakudo, TAP, or DBIish code bases.

t/24-mysql-types-json.rakutest ....... ok
corrupted double-linked list
1..5
    ok 1 - Table created
    ok 2 - Add value: 100 chars
    ok 3 - Add value: 8191 chars
    ok 4 - Add value: 8192 chars
    ok 5 - Add value: 8193 chars
    ok 6 - Add value: 10000 chars
    ok 7 - Add value: 16383 chars
    ok 8 - 6 row
    ok 9 - The object is-a 'Str'
    ok 10 - Value: 100 chars
    ok 11 - The object is-a 'Str'
    ok 12 - Value: 8191 chars
    ok 13 - The object is-a 'Str'
    ok 14 - Value: 8192 chars
    ok 15 - The object is-a 'Str'
    ok 16 - Value: 8193 chars
t/24-mysql-types.rakutest ............ All 5 subtests passed