pip-compile doesn't clean up its temporary directories, generates warnings with PYTHONDEVMODE=1

[si14]

When run with PYTHONDEVMODE=1 pip-compile emits a bunch of warnings like this:

/usr/local/lib/python3.8/tempfile.py:819: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpfrhhtu6jbuild'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/local/lib/python3.8/tempfile.py:819: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmp0o5twtbvsource'>

Quick skim through the sources reveals that temporary directories are created without explicit cleanup. Probably the easiest way to fix it is to use them as context managers.

Environment Versions

1. OS Type: any
2. Python version: 3.8
3. pip version: 20.0.2
4. pip-tools version: 5.3.1

Steps to replicate

1. run PYTHONDEVMODE=1 pip-compile ... on a nontrivial list of dependencies
2. see the warnings

Expected result

No warnings

Actual result

A bunch of warnings

[atugushev]

Hello @si14,

Thanks for the issue. It's fixed in #1233.

[si14]

Thanks a lot!