The bundled selectors library which is used by the local and ssh
connection plugins had a bug which caused a traceback in a cornercase.
If selectors were in use and a syscall was interrupted, selectors would
attempt to restart the syscall after the interrupt was processed. if
the attempt determined that the timeout for running the syscall had
already expired, the code attempted to raise OSError. The raise was
using a Python3-ism and needed to be ported to work on Python2.
Fixes#41630
At the moment, this change will use EPoll on Linux, KQueue on *BSDs,
etc, so it should alleviate problems with too many open file
descriptors.
* Bundle a copy of selectors2 so that we have the selectors API everywhere.
* Add licensing information to selectors2 file so it's clear what the
licensing terms and conditions are.
* Exclude the bundled copy of selectors2 from our boilerplate code-smell test
* Rewrite ssh_run tests to attempt to work around problem with mocking
select on shippable
Fixes#14143
Toshio Kuratomi
Dag Wieers