---
All my old tests work well with the following code, so I've fixed on it

use IPC::Run3;
...
eval {run3
  [
    'cmd',
    'without subshell',
    'and with any complex params 1<>2()[]{*}'
  ],
  'and/now/I/can',
  'redirect/child/streams',
  'from/to/my/files'
};
retcode_full_test_copypasted_from_perldoc_f_system;
if ($@) {
  die("run3 failed but retcode_full_test passed: $@")
}
...
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