creating/binding a socket in a fixture causes it to not close

Describe the bug While creating and binding a socket in a test and then closing it allows the same port to be reopened later in the test, if the socket was originally created and bound in a fixture then it fails claiming OSError: [Errno 98] Address already in use.

To Reproduce Complete input and output below, but the tl;dr is…

================================================= test session starts ==================================================
platform linux -- Python 3.9.5, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: /home/altendky/repos/chia-blockchain
plugins: monitor-1.6.3
collected 2 items                                                                                                      

x.py F.                                                                                                          [100%]

======================================================= FAILURES =======================================================
________________________________________________ test_a_socket[fixture] ________________________________________________

just_a_socket = ('fixture', <socket.socket [closed] fd=-1, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0>)

    def test_a_socket(just_a_socket):
        where, sock = just_a_socket
        if where == "test":
            print("creating and binding in test")
            sock = make_a_bound_socket()
    
        sock.close()
    
        sock2 = socket.socket()
>       sock2.bind(address)
E       OSError: [Errno 98] Address already in use

x.py:37: OSError
------------------------------------------------ Captured stdout setup -------------------------------------------------
creating and binding in fixture
=============================================== short test summary info ================================================
FAILED x.py::test_a_socket[fixture] - OSError: [Errno 98] Address already in use
============================================= 1 failed, 1 passed in 0.09s ==============================================

import socket
import subprocess

import pytest


address = ("127.0.0.1", 33125)

def make_a_bound_socket():
    sock = socket.socket()
    sock.bind(address)
    return sock


@pytest.fixture(params=["fixture", "test"])
def just_a_socket(request):
    where = request.param

    if where == "fixture":
        print("creating and binding in fixture")
        sock = make_a_bound_socket()
    else:
        sock = None

    yield where, sock


def test_a_socket(just_a_socket):
    where, sock = just_a_socket
    if where == "test":
        print("creating and binding in test")
        sock = make_a_bound_socket()

    sock.close()

    sock2 = socket.socket()
    sock2.bind(address)

https://gist.github.com/altendky/656bd59340288be28e8e3eb9a8d6f1b8

Copy/paste this into a terminal in an empty directory on a system with Python 3.9 available

cat > x.py << EOF
import socket
import subprocess

import pytest


address = ("127.0.0.1", 33125)

def make_a_bound_socket():
    sock = socket.socket()
    sock.bind(address)
    return sock


@pytest.fixture(params=["fixture", "test"])
def just_a_socket(request):
    where = request.param

    if where == "fixture":
        print("creating and binding in fixture")
        sock = make_a_bound_socket()
    else:
        sock = None

    yield where, sock


def test_a_socket(just_a_socket):
    where, sock = just_a_socket
    if where == "test":
        print("creating and binding in test")
        sock = make_a_bound_socket()

    sock.close()

    sock2 = socket.socket()
    sock2.bind(address)


def main():
    subprocess.run(["pytest", "--capture", "no", __file__], check=True)


# yuck
if __name__ == "__main__":
    main()
EOF
cat x.py
python3.9 -m venv venv
venv/bin/python --version --version
venv/bin/python -m pip install --upgrade pip setuptools wheel
venv/bin/pip install attrs==21.2.0 iniconfig==1.1.1 packaging==21.3 pluggy==1.0.0 py==1.11.0 pyparsing==3.0.6 pytest==6.2.5 toml==0.10.2
venv/bin/pip freeze
venv/bin/pytest x.py
venv/bin/pip install attrs==21.2.0 certifi==2021.10.8 charset-normalizer==2.0.9 idna==3.3 iniconfig==1.1.1 memory-profiler==0.60.0 packaging==21.3 pluggy==1.0.0 psutil==5.8.0 py==1.11.0 pyparsing==3.0.6 pytest==6.2.5 pytest-monitor==1.6.3 requests==2.26.0 toml==0.10.2 urllib3==1.26.7
venv/bin/pip freeze
venv/bin/pytest x.py
uname -a
lsb_release -a

To get this session

$ cat > x.py << EOF
> import socket
> import subprocess
> 
> import pytest
> 
> 
> address = ("127.0.0.1", 33125)
> 
> def make_a_bound_socket():
>     sock = socket.socket()
>     sock.bind(address)
>     return sock
> 
> 
> @pytest.fixture(params=["fixture", "test"])
> def just_a_socket(request):
>     where = request.param
> 
>     if where == "fixture":
>         print("creating and binding in fixture")
>         sock = make_a_bound_socket()
>     else:
>         sock = None
> 
>     yield where, sock
> 
> 
> def test_a_socket(just_a_socket):
>     where, sock = just_a_socket
>     if where == "test":
>         print("creating and binding in test")
>         sock = make_a_bound_socket()
> 
>     sock.close()
> 
>     sock2 = socket.socket()
>     sock2.bind(address)
> 
> 
> def main():
>     subprocess.run(["pytest", "--capture", "no", __file__], check=True)
> 
> 
> # yuck
> if __name__ == "__main__":
>     main()
> EOF

$ cat x.py
import socket
import subprocess

import pytest


address = ("127.0.0.1", 33125)

def make_a_bound_socket():
    sock = socket.socket()
    sock.bind(address)
    return sock


@pytest.fixture(params=["fixture", "test"])
def just_a_socket(request):
    where = request.param

    if where == "fixture":
        print("creating and binding in fixture")
        sock = make_a_bound_socket()
    else:
        sock = None

    yield where, sock


def test_a_socket(just_a_socket):
    where, sock = just_a_socket
    if where == "test":
        print("creating and binding in test")
        sock = make_a_bound_socket()

    sock.close()

    sock2 = socket.socket()
    sock2.bind(address)


def main():
    subprocess.run(["pytest", "--capture", "no", __file__], check=True)


# yuck
if __name__ == "__main__":
    main()

$ python3.9 -m venv venv

$ venv/bin/python --version --version
Python 3.9.5 (default, Jun  3 2021, 15:18:23) 
[GCC 9.3.0]

$ venv/bin/python -m pip install --upgrade pip setuptools wheel
Requirement already satisfied: pip in ./venv/lib/python3.9/site-packages (21.1.1)
Collecting pip
  Using cached pip-21.3.1-py3-none-any.whl (1.7 MB)
Requirement already satisfied: setuptools in ./venv/lib/python3.9/site-packages (56.0.0)
Collecting setuptools
  Using cached setuptools-60.1.0-py3-none-any.whl (952 kB)
Collecting wheel
  Using cached wheel-0.37.1-py2.py3-none-any.whl (35 kB)
Installing collected packages: wheel, setuptools, pip
  Attempting uninstall: setuptools
    Found existing installation: setuptools 56.0.0
    Uninstalling setuptools-56.0.0:
      Successfully uninstalled setuptools-56.0.0
  Attempting uninstall: pip
    Found existing installation: pip 21.1.1
    Uninstalling pip-21.1.1:
      Successfully uninstalled pip-21.1.1
Successfully installed pip-21.3.1 setuptools-60.1.0 wheel-0.37.1

$ venv/bin/pip install attrs==21.2.0 iniconfig==1.1.1 packaging==21.3 pluggy==1.0.0 py==1.11.0 pyparsing==3.0.6 pytest==6.2.5 toml==0.10.2
Collecting attrs==21.2.0
  Using cached attrs-21.2.0-py2.py3-none-any.whl (53 kB)
Collecting iniconfig==1.1.1
  Using cached iniconfig-1.1.1-py2.py3-none-any.whl (5.0 kB)
Collecting packaging==21.3
  Using cached packaging-21.3-py3-none-any.whl (40 kB)
Collecting pluggy==1.0.0
  Using cached pluggy-1.0.0-py2.py3-none-any.whl (13 kB)
Collecting py==1.11.0
  Using cached py-1.11.0-py2.py3-none-any.whl (98 kB)
Collecting pyparsing==3.0.6
  Using cached pyparsing-3.0.6-py3-none-any.whl (97 kB)
Collecting pytest==6.2.5
  Using cached pytest-6.2.5-py3-none-any.whl (280 kB)
Collecting toml==0.10.2
  Using cached toml-0.10.2-py2.py3-none-any.whl (16 kB)
Installing collected packages: pyparsing, toml, py, pluggy, packaging, iniconfig, attrs, pytest
Successfully installed attrs-21.2.0 iniconfig-1.1.1 packaging-21.3 pluggy-1.0.0 py-1.11.0 pyparsing-3.0.6 pytest-6.2.5 toml-0.10.2

$ venv/bin/pip freeze
attrs==21.2.0
iniconfig==1.1.1
packaging==21.3
pluggy==1.0.0
py==1.11.0
pyparsing==3.0.6
pytest==6.2.5
toml==0.10.2

$ venv/bin/pytest x.py
================================================= test session starts ==================================================
platform linux -- Python 3.9.5, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: /home/altendky/repos/chia-blockchain
collected 2 items                                                                                                      

x.py ..                                                                                                          [100%]

================================================== 2 passed in 0.01s ===================================================

$ venv/bin/pip install attrs==21.2.0 certifi==2021.10.8 charset-normalizer==2.0.9 idna==3.3 iniconfig==1.1.1 memory-profiler==0.60.0 packaging==21.3 pluggy==1.0.0 psutil==5.8.0 py==1.11.0 pyparsing==3.0.6 pytest==6.2.5 pytest-monitor==1.6.3 requests==2.26.0 toml==0.10.2 urllib3==1.26.7
Requirement already satisfied: attrs==21.2.0 in ./venv/lib/python3.9/site-packages (21.2.0)
Collecting certifi==2021.10.8
  Using cached certifi-2021.10.8-py2.py3-none-any.whl (149 kB)
Collecting charset-normalizer==2.0.9
  Using cached charset_normalizer-2.0.9-py3-none-any.whl (39 kB)
Collecting idna==3.3
  Using cached idna-3.3-py3-none-any.whl (61 kB)
Requirement already satisfied: iniconfig==1.1.1 in ./venv/lib/python3.9/site-packages (1.1.1)
Collecting memory-profiler==0.60.0
  Using cached memory_profiler-0.60.0-py3-none-any.whl
Requirement already satisfied: packaging==21.3 in ./venv/lib/python3.9/site-packages (21.3)
Requirement already satisfied: pluggy==1.0.0 in ./venv/lib/python3.9/site-packages (1.0.0)
Collecting psutil==5.8.0
  Using cached psutil-5.8.0-cp39-cp39-manylinux2010_x86_64.whl (293 kB)
Requirement already satisfied: py==1.11.0 in ./venv/lib/python3.9/site-packages (1.11.0)
Requirement already satisfied: pyparsing==3.0.6 in ./venv/lib/python3.9/site-packages (3.0.6)
Requirement already satisfied: pytest==6.2.5 in ./venv/lib/python3.9/site-packages (6.2.5)
Collecting pytest-monitor==1.6.3
  Using cached pytest_monitor-1.6.3-py3-none-any.whl (14 kB)
Collecting requests==2.26.0
  Using cached requests-2.26.0-py2.py3-none-any.whl (62 kB)
Requirement already satisfied: toml==0.10.2 in ./venv/lib/python3.9/site-packages (0.10.2)
Collecting urllib3==1.26.7
  Using cached urllib3-1.26.7-py2.py3-none-any.whl (138 kB)
Requirement already satisfied: wheel in ./venv/lib/python3.9/site-packages (from pytest-monitor==1.6.3) (0.37.1)
Installing collected packages: urllib3, psutil, idna, charset-normalizer, certifi, requests, memory-profiler, pytest-monitor
Successfully installed certifi-2021.10.8 charset-normalizer-2.0.9 idna-3.3 memory-profiler-0.60.0 psutil-5.8.0 pytest-monitor-1.6.3 requests-2.26.0 urllib3-1.26.7

$ venv/bin/pip freeze
attrs==21.2.0
certifi==2021.10.8
charset-normalizer==2.0.9
idna==3.3
iniconfig==1.1.1
memory-profiler==0.60.0
packaging==21.3
pluggy==1.0.0
psutil==5.8.0
py==1.11.0
pyparsing==3.0.6
pytest==6.2.5
pytest-monitor==1.6.3
requests==2.26.0
toml==0.10.2
urllib3==1.26.7

$ venv/bin/pytest x.py
================================================= test session starts ==================================================
platform linux -- Python 3.9.5, pytest-6.2.5, py-1.11.0, pluggy-1.0.0
rootdir: /home/altendky/repos/chia-blockchain
plugins: monitor-1.6.3
collected 2 items                                                                                                      

x.py F.                                                                                                          [100%]

======================================================= FAILURES =======================================================
________________________________________________ test_a_socket[fixture] ________________________________________________

just_a_socket = ('fixture', <socket.socket [closed] fd=-1, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0>)

    def test_a_socket(just_a_socket):
        where, sock = just_a_socket
        if where == "test":
            print("creating and binding in test")
            sock = make_a_bound_socket()
    
        sock.close()
    
        sock2 = socket.socket()
>       sock2.bind(address)
E       OSError: [Errno 98] Address already in use

x.py:37: OSError
------------------------------------------------ Captured stdout setup -------------------------------------------------
creating and binding in fixture
=============================================== short test summary info ================================================
FAILED x.py::test_a_socket[fixture] - OSError: [Errno 98] Address already in use
============================================= 1 failed, 1 passed in 0.09s ==============================================

$ uname -a
Linux p1 5.4.0-91-generic #102-Ubuntu SMP Fri Nov 5 16:31:28 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.3 LTS
Release:        20.04
Codename:       focal

Expected behavior I expect sockets created and bound in a fixture to be able to be closed.

Desktop (please complete the following information):

• OS: Linux (Ubuntu 20.04.3 LTS)
• Python version: Python 3.9.5 (default, Jun 3 2021, 15:18:23) [GCC 9.3.0]
• Pytest version: 6.2.5
• pytest-monitor version: 1.6.3

Additional context I probably won’t get to it tonight, but I will try to see what I can learn about pytest-monitor towards the end of fixing this. I tested back to pytest-monitor v1.0.0 and it seems to be present throughout.

[altendky]

Already filed a bug there since I could recreate with just it. Link above. I’ll follow up there if I manage any more debugging.

[js-dieu]

Ok got your point. My intuition drives me to memory_profiler at first glance since the profiling launches a monitoring process apart. I’ll check this out next week…