httpx 0.19.0 with eventlet causes RecursionError

[bobh66]

This is really an eventlet issue, which I will document in that repo, but I wanted to mention it here in case anyone sees the same problem.

When running httpx==0.19.0 with eventlet, the eventlet monkey_patch() replaces the SSLContext object with a GreenSSLContext object which does not handle setting the minimum TLS version correctly and results in RecursionErrors when creating an httpx Client.

For example, if you run:

from eventlet import monkey_patch
import ssl
monkey_patch()
from httpx import Client

x = Client()

with httpx==0.19.0 it results in:

Traceback (most recent call last):
  File "eventletfoo.py", line 5, in <module>
    x = Client()
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_client.py", line 648, in __init__
    self._transport = self._init_transport(
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_client.py", line 696, in _init_transport
    return HTTPTransport(
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_transports/default.py", line 129, in __init__
    ssl_context = create_ssl_context(verify=verify, cert=cert, trust_env=trust_env)
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_config.py", line 50, in create_ssl_context
    return SSLConfig(
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_config.py", line 74, in __init__
    self.ssl_context = self.load_ssl_context()
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_config.py", line 86, in load_ssl_context
    return self.load_ssl_context_verify()
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_config.py", line 123, in load_ssl_context_verify
    context = self._create_default_ssl_context()
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_config.py", line 158, in _create_default_ssl_context
    set_minimum_tls_version_1_2(context)
  File "/home/bobh/PyCharmProjects/python-backend/.tox/dev/lib/python3.8/site-packages/httpx/_compat.py", line 37, in set_minimum_tls_version_1_2
    context.minimum_version = ssl.TLSVersion.TLSv1_2
  File "/usr/lib/python3.8/ssl.py", line 586, in minimum_version
    super(SSLContext, SSLContext).minimum_version.__set__(self, value)
  File "/usr/lib/python3.8/ssl.py", line 586, in minimum_version
    super(SSLContext, SSLContext).minimum_version.__set__(self, value)
  File "/usr/lib/python3.8/ssl.py", line 586, in minimum_version
    super(SSLContext, SSLContext).minimum_version.__set__(self, value)
  [Previous line repeated 490 more times]
  File "/usr/lib/python3.8/ssl.py", line 584, in minimum_version
    if value == TLSVersion.SSLv3:
RecursionError: maximum recursion depth exceeded while calling a Python object

because the GreenSSLContext does not handle the minimum_version property of SSLContext properly.

It works fine with 0.18.2

I will open an issue with eventlet, they have the same problem with other SSLContext properties, but I wanted to make this info available here so others don't have to spend the time debugging.

[bobh66]

I opened eventlet/eventlet#726 and pushed a PR to resolve this in eventlet

[bobh66]

The eventlet patch eventlet/eventlet#727 is merged and should be included in the next release