* Move retry logic into _ssh_retry decorator, and apply to exec_command, put_file and fetch_file
* Update tests to reflect change
* Move _ssh_retry to _run, and update tests to reflect
* piped should use exec_command instead of removed _exec_command
* Rework tests to support selectors instead of select.select
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
* Replace pipes.quote for shlex_quote
* More migration of pipes.quote to shlex_quote
Note that we cannot yet move module code over. Modules have six-1.4
bundled which does not have shlex_quote. This shouldn't be a problem as
the function is still importable from pipes.quote. It's just that this
has become an implementation detail that makes us want to import from
shlex instead.
Once we get rid of the python2.4 dependency we can update to a newer
version of bundled six module-side and then we're free to use
shlex_quote everywhere.
