pytest failed to run on windows: OSError: [WinError 87]

[siben168]

I'm using a clean virtual env on windows 7 with python 3.7.4, the pytest is always failed with a OSError as below, on the same machine, i have succeeded to run the pytest on same code with a previou python version, is this related to an upgrade with python?

(calculator) D:\workspace\CalculatorLibrary>pytest -h
Traceback (most recent call last):
  File "d:\python37\Lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "d:\python37\Lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "D:\workspace\calculator\Scripts\pytest.exe\__main__.py", line 9, in <module>
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 55, in main
    config = _prepareconfig(args, plugins)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 200, in _prepareconfig
    pluginmanager=pluginmanager, args=args
  File "d:\workspace\calculator\lib\site-packages\pluggy\hooks.py", line 289, in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 87, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 81, in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 203, in _multicall
    gen.send(outcome)
  File "d:\workspace\calculator\lib\site-packages\_pytest\helpconfig.py", line 89, in pytest_cmdline_parse
    config = outcome.get_result()
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 80, in get_result
    raise ex[1].with_traceback(ex[2])
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 187, in _multicall
    res = hook_impl.function(*args)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 661, in pytest_cmdline_parse
    self.parse(args)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 869, in parse
    self._preparse(args, addopts=addopts)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 825, in _preparse
    early_config=self, args=args, parser=self._parser
  File "d:\workspace\calculator\lib\site-packages\pluggy\hooks.py", line 289, in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 87, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 81, in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 208, in _multicall
    return outcome.get_result()
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 80, in get_result
    raise ex[1].with_traceback(ex[2])
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 182, in _multicall
    next(gen)  # first yield
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 42, in pytest_load_initial_conftests
    _py36_windowsconsoleio_workaround(sys.stdout)
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 815, in _py36_windowsconsoleio_workaround
    sys.stdin = _reopen_stdio(sys.stdin, "rb")
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 808, in _reopen_stdio
    open(os.dup(f.fileno()), mode, buffering),
OSError: [WinError 87] 参数错误。

[nicoddemus]

Strange. Is there any chance of you editing the capture.py file shown in the traceback and commenting out the call to _py36_windowsconsoleio_workaround?

[siben168]

Strange. Is there any chance of you editing the capture.py file shown in the traceback and commenting out the call to _py36_windowsconsoleio_workaround?

I've tried to comment out the call to '_py36_windowsconsoleio_workaround(sys.stdout)', and another expection occurred

if ns.capture == "fd":
        pass
        #_py36_windowsconsoleio_workaround(sys.stdout)

errors captured:

(calculator) D:\workspace>pytest -h
Traceback (most recent call last):
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 200, in _prepareconfig
    pluginmanager=pluginmanager, args=args
  File "d:\workspace\calculator\lib\site-packages\pluggy\hooks.py", line 289, in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 87, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 81, in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 203, in _multicall
    gen.send(outcome)
  File "d:\workspace\calculator\lib\site-packages\_pytest\helpconfig.py", line 89, in pytest_cmdline_parse
    config = outcome.get_result()
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 80, in get_result
    raise ex[1].with_traceback(ex[2])
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 187, in _multicall
    res = hook_impl.function(*args)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 661, in pytest_cmdline_parse
    self.parse(args)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 869, in parse
    self._preparse(args, addopts=addopts)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 825, in _preparse
    early_config=self, args=args, parser=self._parser
  File "d:\workspace\calculator\lib\site-packages\pluggy\hooks.py", line 289, in __call__
    return self._hookexec(self, self.get_hookimpls(), kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 87, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "d:\workspace\calculator\lib\site-packages\pluggy\manager.py", line 81, in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
  File "d:\workspace\calculator\lib\site-packages\pluggy\callers.py", line 203, in _multicall
    gen.send(outcome)
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 56, in pytest_load_initial_conftests
    capman.suspend_global_capture()
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 130, in suspend_global_capture
    cap.suspend_capturing(in_=in_)
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 492, in suspend_capturing
    self.out.suspend()
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 600, in suspend
    self.syscapture.suspend()
AttributeError: 'FDCapture' object has no attribute 'syscapture'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "d:\python37\Lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "d:\python37\Lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "D:\workspace\calculator\Scripts\pytest.exe\__main__.py", line 9, in <module>
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 55, in main
    config = _prepareconfig(args, plugins)
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 203, in _prepareconfig
    config._ensure_unconfigure()
  File "d:\workspace\calculator\lib\site-packages\_pytest\config\__init__.py", line 654, in _ensure_unconfigure
    fin()
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 117, in stop_global_capturing
    self._global_capturing.pop_outerr_to_orig()
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 482, in pop_outerr_to_orig
    out, err = self.readouterr()
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 524, in readouterr
    self.out.snap() if self.out is not None else "",
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 625, in snap
    res = super().snap()
  File "d:\workspace\calculator\lib\site-packages\_pytest\capture.py", line 583, in snap
    self.tmpfile.seek(0)
AttributeError: 'FDCapture' object has no attribute 'tmpfile'

[siben168]

I have reinstalled to use python 3.7.3, and everything works just fine, it seems a compatibility issue between python 3.7.4 and pytest.

[nicoddemus]

Thanks!

That's really strange. I've just installed python 3.7.4 here on Windows and pytest -h works fine for me.

Can you translate what OSError: [WinError 87] 参数错误。 means? Also, are you using 32 or 64-bit Python? You can check the banner for that information:

λ python
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul  8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

[nicoddemus]

Can you translate what OSError: [WinError 87] 参数错误。 means?

Or I can use Google Translate, duh. It means "Parameter error". Hmm...

[The-Compiler]

Looks like https://bugs.python.org/issue37549 - it only happens on Windows 7 (not Windows 10) which might explain why @nicoddemus can't reproduce it.

[nicoddemus]

Oh sorry, I've missed that important bit of information. Thanks Florian!

[nicoddemus]

Woot, merged to 3.7 branch:

https://github.com/python/cpython/pull/15438

So this will be fixed by upstream 3.7.5 it seems.

[nicoddemus]

Closing this for now given that this was fixed upstream. 👍

[rahul-kothari]

Although this is pytest-dev github repo, I would like to highlight that you get the same error even when not testing. I am using a venv and was just reading data from a socket connection.

[The-Compiler]

@rahul-ki Indeed! "OSError: [WinError 87] The parameter is incorrect." boils down to "Python called some function in the Windows API, and Windows thinks that it was called the wrong way" - there's a lot of reasons why that can happen.

[gkazarkin]

Windows 10, python 3.8.1, pytest 5.3.3 (same 5.3.4) = INTERNALERROR> OSError: [WinError 87]

platform win32 -- Python 3.8.1, pytest-5.3.3, py-1.8.1, pluggy-0.13.1 -- C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\python.exe
cachedir: .pytest_cache
metadata: {'Python': '3.8.1', 'Platform': 'Windows-10-10.0.17134-SP0', 'Packages': {'pytest': '5.3.3', 'py': '1.8.1', 'pluggy': '0.13.1'}, 'Plugins': {'forked': '1.1.3', 'html': '2.0.1', 'metadata': '1.8.0', 'rerunfailures': '8.0', 'splinter': '2.0.1', 'xdist': '1.31.0'}, 'JAVA_HOME': 'C:\\Program Files\\Java\\jdk1.8.0_201'}
rootdir: C:\Users\gkazarkin\Desktop\Code\GOp\qa, inifile: pytest.ini
plugins: forked-1.1.3, html-2.0.1, metadata-1.8.0, rerunfailures-8.0, splinter-2.0.1, xdist-1.31.0
gw0 I / gw1 I / gw2 I / gw3 I / gw4 I
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\_pytest\main.py", line 194, in wrap_session
INTERNALERROR>     config.hook.pytest_sessionstart(session=session)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\pluggy\hooks.py", line 286, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\pluggy\manager.py", line 93, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\pluggy\manager.py", line 84, in <lambda>
INTERNALERROR>     self._inner_hookexec = lambda hook, methods, kwargs: hook.multicall(
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\pluggy\callers.py", line 208, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\pluggy\callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\pluggy\callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\xdist\dsession.py", line 78, in pytest_sessionstart
INTERNALERROR>     nodes = self.nodemanager.setup_nodes(putevent=self.queue.put)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\xdist\workermanage.py", line 64, in setup_nodes
INTERNALERROR>     nodes.append(self.setup_node(spec, putevent))
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\xdist\workermanage.py", line 68, in setup_node
INTERNALERROR>     gw = self.group.makegateway(spec)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\execnet\multi.py", line 133, in makegateway
INTERNALERROR>     io = gateway_io.create_io(spec, execmodel=self.execmodel)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\execnet\gateway_io.py", line 118, in create_io
INTERNALERROR>     return Popen2IOMaster(args, execmodel)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\execnet\gateway_io.py", line 21, in __init__
INTERNALERROR>     self.popen = p = execmodel.PopenPiped(args)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\site-packages\execnet\gateway_base.py", line 184, in PopenPiped
INTERNALERROR>     return self.subprocess.Popen(args, stdout=PIPE, stdin=PIPE)
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\subprocess.py", line 854, in __init__
INTERNALERROR>     self._execute_child(args, executable, preexec_fn, close_fds,
INTERNALERROR>   File "C:\Users\gkazarkin\AppData\Local\Programs\Python\Python38\lib\subprocess.py", line 1307, in _execute_child
INTERNALERROR>     hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
INTERNALERROR> OSError: [WinError 87]

[gkazarkin]

works until pytest/4.6.9/ or lower
since 5.0.0+ = OSError: [WinError 87]

[RonnyPfannschmidt]

@gkazarkin thats a ydist/execnet issue unrelated to the orginal issue, please open a new one

[guifran001]

windows 7
pytest 5.4.1
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul 8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32

Got the problem OSError: [WinError 87]
Set environment variable PYTHONLEGACYWINDOWSSTDIO and the error changed for:

```Traceback (most recent call last):
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 258, in _prepareconfig
pluginmanager=pluginmanager, args=args
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\hooks.py", line 286, in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\manager.py", line 93, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\manager.py", line 87, in
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\callers.py", line 203, in _multicall
gen.send(outcome)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\helpconfig.py", line 90, in pytest_cmdline_parse
config = outcome.get_result()
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\callers.py", line 80, in get_result
raise ex[1].with_traceback(ex[2])
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\callers.py", line 187, in _multicall
res = hook_impl.function(*args)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 836, in pytest_cmdline_parse
self.parse(args)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 1044, in parse
self._preparse(args, addopts=addopts)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 1002, in _preparse
early_config=self, args=args, parser=self._parser
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\hooks.py", line 286, in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\manager.py", line 93, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\manager.py", line 87, in
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
File "c:\work\git\productiongenerator\venv\lib\site-packages\pluggy\callers.py", line 203, in _multicall
gen.send(outcome)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 68, in pytest_load_initial_conftests
capman.suspend_global_capture()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 142, in suspend_global_capture
cap.suspend_capturing(in_=in_)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 484, in suspend_capturing
self.out.suspend()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 602, in suspend
self.syscapture.suspend()
AttributeError: 'FDCapture' object has no attribute 'syscapture'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "c:\users\guifran001appdata\local\programs\python\python37Lib\runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "c:\users\guifran001appdata\local\programs\python\python37Lib\runpy.py", line 85, in _run_code
exec(code, run_globals)
File "C:\work\git\productiongenerator\venv\Scripts\pytest.exe__main__.py", line 7, in
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 105, in main
config = _prepareconfig(args, plugins)
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 261, in _prepareconfig
config._ensure_unconfigure()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytest\config__init__.py", line 829, in _ensure_unconfigure

fin()

File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 129, in stop_global_capturing
self._global_capturing.pop_outerr_to_orig()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 474, in pop_outerr_to_orig
out, err = self.readouterr()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 515, in readouterr
out = self.out.snap()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 628, in snap
res = super().snap()
File "c:\work\git\productiongenerator\venv\lib\site-packages_pytestcapture.py", line 585, in snap
self.tmpfile.seek(0)
AttributeError: 'FDCapture' object has no attribute 'tmpfile'
```

[Nitin4994]

Where is solution??

[nicoddemus]

See here: https://github.com/pytest-dev/pytest/issues/5724#issuecomment-524429916