with "-X dev": ResourceWarning: unclosed <ssl.SSLSocket fd=4 ...

❓ I’m submitting a …

• 🐞 bug report
• 🐣 feature request
• ❓ question about the decisions made in the repository

🐞 Describe the bug. What is the current behavior? With python3 -X dev -X tracemalloc=5 on cheroot code with SSL, python gives a ResourceWarning

❓ What is the motivation / use case for changing the behavior?

A python ResourceWarning is an good indication code can be improved: it’s not closing a resource. It generates warnings in other code (SABnzbd) this is using cherrypy / cheroot (when running that code with -X dev), which makes cleaning up own code more difficult.

💡 To Reproduce

$ python3 -X dev -X tracemalloc=5 cheroot_only.py 
/usr/lib/python3.8/threading.py:870: ResourceWarning: unclosed <ssl.SSLSocket fd=4, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
  self._target(*self._args, **self._kwargs)
Object allocated at (most recent call last):
  File "/usr/lib/python3.8/threading.py", lineno 932
    self.run()
  File "/usr/lib/python3.8/threading.py", lineno 870
    self._target(*self._args, **self._kwargs)
  File "/home/sander/.local/lib/python3.8/site-packages/cheroot/ssl/builtin.py", lineno 68
    target=lambda: context.wrap_socket(
  File "/usr/lib/python3.8/ssl.py", lineno 500
    return self.sslsocket_class._create(
  File "/usr/lib/python3.8/ssl.py", lineno 1003
    self = cls.__new__(cls, **kwargs)
/home/sander/.local/lib/python3.8/site-packages/cheroot/ssl/builtin.py:75: ResourceWarning: unclosed <ssl.SSLSocket fd=3, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
  return context.wrap_socket(
Object allocated at (most recent call last):
  File "/home/sander/.local/lib/python3.8/site-packages/cheroot/ssl/builtin.py", lineno 198
    _parse_cert(certificate, private_key, self.certificate_chain),
  File "/home/sander/.local/lib/python3.8/site-packages/cheroot/ssl/builtin.py", lineno 94
    return _loopback_for_cert(certificate, private_key, certificate_chain)
  File "/home/sander/.local/lib/python3.8/site-packages/cheroot/ssl/builtin.py", lineno 75
    return context.wrap_socket(
  File "/usr/lib/python3.8/ssl.py", lineno 500
    return self.sslsocket_class._create(
  File "/usr/lib/python3.8/ssl.py", lineno 1003
    self = cls.__new__(cls, **kwargs)

with this code:

#!/usr/bin/python3

from cheroot import wsgi
def my_crazy_app(environ, start_response):
    status = '200 OK'
    response_headers = [('Content-type','text/plain')]
    start_response(status, response_headers)
    return [b'Hello world!']
addr = '0.0.0.0', 8070
server = wsgi.Server(addr, my_crazy_app)

# the SSL stuff:
from cheroot.server import get_ssl_adapter_class
server.ssl_adapter = get_ssl_adapter_class(name='builtin')('./server.cert', './server.key')

server.start()

💡 Expected behavior No ResourceWarning

📋 Details See above

📋 Environment

• Cheroot version: 8.3.0
• CherryPy version: 18.5.0
• Python version: 3.8
• OS: Ubuntu 20.04
• Browser: not involved to get ResourceWarning

📋 Additional context

Related to https://github.com/sabnzbd/sabnzbd/issues/1489

[webknjaz]

@mxii-ca @sanderjo yeah, I know that Python tracks resources like that, and even though this leakage is minor, I’d like to have it closed correctly. So a PR would be appreciated.

[webknjaz]

Mind updating the issue at the top with the new repro?