带有 python 3.8 的 Msys2：ImportError: cannot import name 'open_code' from 'io'

Question

注意：根据 cmets，对该问题进行了多次编辑。它们如下所示，并用线分隔。 截至目前，唯一剩下的问题似乎是 numpy 无法加载，可能（但不确定）由于存在两个替代 python 3.8 系统。

几个月前我更新了我的 msys2 系统。 这显然包括从 python 3.7 到 3.8 的更新，但这给我留下了两个损坏的 python：我可以在 3.7 时启动 python，但没有关联的包，当它是 3.8 时我无法启动 python，这是包含软件包的版本。 我不知道这出了什么问题，或者我做错了什么。 我现在才注意到这一点，我的意思是升级后再次使用 python。

我将在这里描述我遵循的一系列步骤以及我发现的内容。 为了清楚起见，我将在下面发布支持代码。

1. 我可以启动python，但是在python中找不到pandas（例如）和许多其他包。 进一步检查，/mingw64/lib/python3.7/site-packages 基本上是空的（升级到 3.8 时肯定是空的）。

2. 寻找pandas 包，我发现我安装了一个版本。

3. pandas 版本适用于 python 3.8，肯定是从 3.7 升级而来的。

4. 我将 PYTHONPATH 从 3.7 重定向到 3.8

5. 现在我什至无法启动 python。 编辑现在我可以启动 python，但有一些错误配置问题（即部分修复）。

现在的问题是

如何修复python3.8，出现以下错误？

ImportError: cannot import name 'open_code' from 'io' (unknown location)

如何修复python3.8，出现以下问题？

新问题：

5.1。我应该让 python 指向 3.8，并修复包。

5.2。有些模块没有找到，有些是。

注意：我不知道Msys2 upgrade breaks python2-pyqt5 是否与此有关。

相关：

https://github.com/tox-dev/tox/issues/1334

https://github.com/yan12125/python3-android/issues/19

https://python-forum.io/Thread-Fatal-Python-error-init-sys-streams-can-t-initialize-sys-standard-streams-Attribute

---

TL;DR：支持代码

1. pandas 未找到

   $ python
   Python 3.7.4 (default, Jul 11 2019, 10:29:54)
   [GCC 9.1.0] on msys
   Type "help", "copyright", "credits" or "license" for more information.
   Reading /home/user1/.pythonrc
   readline is in /usr/lib/python3.7/lib-dynload/readline.cpython-37m.dll
   >>> import pandas
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   ModuleNotFoundError: No module named 'pandas'
   >>>
   

2. pandas 已实际安装

   $ pacman -Sl | grep python | grep installed
   mingw64 mingw-w64-x86_64-python 3.8.2-1 [installed: 3.8.1-1]
   mingw64 mingw-w64-x86_64-python-apipkg 1.5-1 [installed]
   ...
   mingw64 mingw-w64-x86_64-python-pandas 1.0.3-1 [installed: 1.0.1-1]
   ...
   mingw64 mingw-w64-x86_64-python2-setuptools 44.1.0-1 [installed: 42.0.2-1]
   msys python 3.7.4-1 [installed]
   msys python2 2.7.17-1 [installed]
   

3. 我的pandas 版本适用于 python 3.8

   $ pacman -Ql mingw-w64-x86_64-python-pandas | head -5
   mingw-w64-x86_64-python-pandas /mingw64/
   mingw-w64-x86_64-python-pandas /mingw64/lib/
   mingw-w64-x86_64-python-pandas /mingw64/lib/python3.8/
   mingw-w64-x86_64-python-pandas /mingw64/lib/python3.8/site-packages/
   mingw-w64-x86_64-python-pandas /mingw64/lib/python3.8/site-packages/pandas-1.0.1-py3.8.egg-info/
   

4. 我将 PYTHONPATH 从 3.7 重定向到 3.8

   改变了

   export PYVERSION="3.7"
   export PYTHONDIR2="${MINGW_HOME}/lib/python${PYVERSION}"
   export PYTHONPATH="${PYTHONDIR2}:${PYTHONDIR2}/site-packages"
   

   到

   export PYVERSION="3.8"
   ...
   

5. 现在我什至无法启动 python。 编辑：老问题：

   $ python
   Fatal Python error: init_sys_streams: can't initialize sys standard streams
   Traceback (most recent call last):
     File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/io.py", line 54, in <module>
   ImportError: cannot import name 'open_code' from 'io' (unknown location)
   Aborted (core dumped)
   

新问题：

$ python --version
Python 3.7.4
$ type python
python is hashed (/usr/bin/python)
$ ls /usr/bin/python
/usr/bin/python
$ python3.8
Python 3.8.2 (default, Apr  9 2020, 13:17:39)  [GCC 9.3.0 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
Reading C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/home/user1/.pythonrc
Module readline not available.
Traceback (most recent call last):
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/home/user1/.pythonrc", line 42, in <module>
    del os, atexit, readline, rlcompleter, save_history, historyPath
NameError: name 'readline' is not defined
>>> import readline
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'readline'
>>> import zipfile
>>> import pandas
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pandas/__init__.py", line 16, in <module>
    raise ImportError(
ImportError: Unable to import required dependencies:
numpy: DLL load failed while importing _ctypes: No se puede encontrar el módulo especificado.
>>> import numpy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/__init__.py", line 142, in <module>
    from . import core
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/core/__init__.py", line 106, in <module>
    from . import _dtype_ctypes
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/core/_dtype_ctypes.py", line 25, in <module>
    import _ctypes
ImportError: DLL load failed while importing _ctypes: No se puede encontrar el módulo especificado.
>>> exit()
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'readline'

---

EDIT #2：根据要求添加信息。 我刚刚注意到我没有pip。这与我从未使用pip 安装任何软件包的事实相匹配...

$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/opt/bin:/c/Windows/System32:/c/Windows:/c/Windows/System32/Wbem:/c/Windows/System32/WindowsPowerShell/v1.0/:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/c/Users/user1/OneDrive/Documents/soft-hard-ware/linux-ubuntu:/c/Users/user1/OneDrive/Documents/soft-hard-ware/linux-ubuntu/rsync:/c/Users/user1/Documents/appls_mydocs/science-math-visualization/gp524-win64-mingw_3/gnuplot/bin:/mingw64/bin
$ echo $PYTHONPATH
/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8:/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages
$ echo $PYTHONSTARTUP
/home/user1/.pythonrc
$ which python3.8
/mingw64/bin/python3.8
$ python3.8 -m pip freeze
C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/bin/python3.8.exe: No module named pip
$ python3.8 -c "import sys; print(sys.builtin_module_names)"
('_abc', '_ast', '_codecs', '_collections', '_functools', '_imp', '_io', '_locale', '_operator', '_signal', '_sre', '_stat', '_string', '_symtable', '_thread', '_tracemalloc', '_warnings', '_weakref', '_winapi', 'atexit', 'builtins', 'errno', 'faulthandler', 'gc', 'itertools', 'marshal', 'msvcrt', 'nt', 'sys', 'time', 'winreg', 'xxsubtype')

编辑#3： 按要求发布，以及其他信息。

$ cat .pythonrc
import os
print( "Reading " + os.path.realpath(__file__) )

# enable syntax completion
try:
    import readline
    print( "readline is in " + readline.__file__ )
except ImportError:
    print("Module readline not available.")
else:
    import rlcompleter
    readline.parse_and_bind("tab: complete")

# From https://docs.python.org/2/tutorial/interactive.html

# Add auto-completion and a stored history file of commands to your Python
# interactive interpreter. Requires Python 2.0+, readline. Autocomplete is
# bound to the Esc key by default (you can change it - see readline docs).
#
# Store the file in ~/.pystartup, and set an environment variable to point
# to it:  "export PYTHONSTARTUP=~/.pystartup" in bash.

import atexit
import os
#import readline
#import rlcompleter

historyPath = os.path.expanduser("~/.pyhistory")

def save_history(historyPath=historyPath):
    import readline
    readline.write_history_file(historyPath)

if os.path.exists(historyPath):
    #import readline
    readline.read_history_file(historyPath)

atexit.register(save_history)
del os, atexit, readline, rlcompleter, save_history, historyPath

我不明白为什么 which python3.8 和 PYTHONPATH 不同步：

$ cygpath -w $(which python3.8)
C:\Users\user1\Documents\appls_mydocs\PortableApps\MSYS2Portable\App\msys32\mingw64\bin\python3.8.exe
$ echo $PYTHONPATH
/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8:/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages
$ cygpath -w /c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8
C:\Users\user1\Documents\appls_mydocs\PortableApps\MSYS2Portable\App\msys32\mingw64\lib\python3.8
$ cygpath -w /c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages
C:\Users\user1\Documents\appls_mydocs\PortableApps\MSYS2Portable\App\msys32\mingw64\lib\python3.8\site-packages
$ which python
/usr/bin/python

我似乎有两个不完整/损坏的 python 安装（3.7、3.8）。 我不知道是什么导致了“不完整”的升级。 一些观察（见下面的代码）：

1. python 指向 3.7

2. readline 适用于 3.7 而不适用于 3.8。 我不知道为什么。

3. pandas（以及许多其他）适用于 3.8 而不适用于 3.7。 由于缺少依赖项（我猜这些依赖项在 3.7 中可用），它们中的许多无论如何都不会在 3.8 中导入。 我不知道为什么。

4. python3.8 以 Windows 格式报告.pythonrc 的位置，而 3.7 以 Cygwin 格式报告它。 这正常吗？

5. 删除 PYTHONPATH 没有帮助。

$ unset PYTHONPATH
$ python3.8
Python 3.8.2 (default, Apr  9 2020, 13:17:39)  [GCC 9.3.0 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
Reading C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/home/user1/.pythonrc
Module readline not available.
Traceback (most recent call last):
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/home/user1/.pythonrc", line 42, in <module>
    del os, atexit, readline, rlcompleter, save_history, historyPath
NameError: name 'readline' is not defined
>>> import pandas
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pandas/__init__.py", line 16, in <module>
    raise ImportError(
ImportError: Unable to import required dependencies:
numpy: DLL load failed while importing _ctypes: No se puede encontrar el módulo especificado.
>>> exit()
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'readline'
$ python
Python 3.7.4 (default, Jul 11 2019, 10:29:54)
[GCC 9.1.0] on msys
Type "help", "copyright", "credits" or "license" for more information.
Reading /home/user1/.pythonrc
readline is in /usr/lib/python3.7/lib-dynload/readline.cpython-37m.dll
>>> import pandas
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'pandas'
>>> exit()

---

编辑#4：

我检查了所有 python 包，发现了一些奇怪的东西。似乎基本的 python 安装包含两个单独的包，一个 mingw64 和另一个 msys。 我不知道每个人是做什么的。

$ pacman -Sl | grep "python" | grep "installed"
...
mingw64 mingw-w64-x86_64-python 3.8.2-2 [installed]
...
msys python 3.8.2-1 [installed: 3.7.4-1]
...

一方面，安装的版本 mingw64 (3.8.2-2) 与 msys (3.7.4-1) 不匹配。 另一方面，(3.8.2-2) 和 (3.8.2-1) 的可用颠覆并不完全相同。 无论如何，我继续升级 msys python，这大大解决了问题。

$ pacman -S python
...
$ python
Python 3.8.2 (default, Apr 16 2020, 15:31:48)
[GCC 9.3.0] on msys
Type "help", "copyright", "credits" or "license" for more information.
Reading /home/user1/.pythonrc
Traceback (most recent call last):
  File "/home/user1/.pythonrc", line 9, in <module>
    import readline
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/readline.py", line 6, in <module>
    from pyreadline.rlmain import Readline
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pyreadline/__init__.py", line 12, in <module>
    from . import logger, clipboard, lineeditor, modes, console
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pyreadline/clipboard/__init__.py", line 13, in <module>
    from .win32_clipboard import GetClipboardText, SetClipboardText
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pyreadline/clipboard/win32_clipboard.py", line 37, in <module>
    import ctypes.wintypes as wintypes
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/ctypes/wintypes.py", line 20, in <module>
    class VARIANT_BOOL(ctypes._SimpleCData):
ValueError: _type_ 'v' not supported
Failed calling sys.__interactivehook__
Traceback (most recent call last):
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site.py", line 412, in register_readline
    import readline
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/readline.py", line 6, in <module>
    from pyreadline.rlmain import Readline
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pyreadline/__init__.py", line 12, in <module>
    from . import logger, clipboard, lineeditor, modes, console
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pyreadline/clipboard/__init__.py", line 13, in <module>
    from .win32_clipboard import GetClipboardText, SetClipboardText
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/pyreadline/clipboard/win32_clipboard.py", line 37, in <module>
    import ctypes.wintypes as wintypes
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/ctypes/wintypes.py", line 20, in <module>
    class VARIANT_BOOL(ctypes._SimpleCData):
ValueError: _type_ 'v' not supported

所以我现在在 3.8 中有 readline。但是在加载.pythonrc 的过程中会弹出另一个问题。

另外，numpy 存在问题。 它并非源于 python 版本（/usr/bin/python 现在指向 3.8）。

$ python --version
Python 3.8.2
$ python
...
>>> import numpy
Traceback (most recent call last):
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/core/__init__.py", line 24, in <module>
    from . import multiarray
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/core/multiarray.py", line 14, in <module>
    from . import overrides
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/core/overrides.py", line 7, in <module>
    from numpy.core._multiarray_umath import (
ModuleNotFoundError: No module named 'numpy.core._multiarray_umath'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/__init__.py", line 142, in <module>
    from . import core
  File "/c/Users/user1/Documents/appls_mydocs/PortableApps/MSYS2Portable/App/msys32/mingw64/lib/python3.8/site-packages/numpy/core/__init__.py", line 54, in <module>
    raise ImportError(msg)
ImportError:

IMPORTANT: PLEASE READ THIS FOR ADVICE ON HOW TO SOLVE THIS ISSUE!

Importing the numpy c-extensions failed.
- Try uninstalling and reinstalling numpy.
- If you have already done that, then:
  1. Check that you expected to use Python3.8 from "/usr/bin/python.exe",
     and that you have no directories in your PATH or PYTHONPATH that can
     interfere with the Python and numpy version "1.18.3" you're trying to use.
  2. If (1) looks fine, you can open a new issue at
     https://github.com/numpy/numpy/issues.  Please include details on:
     - how you installed Python
     - how you installed numpy
     - your operating system
     - whether or not you have multiple versions of Python installed
     - if you built from source, your compiler versions and ideally a build log

- If you're working with a numpy git repository, try `git clean -xdf`
  (removes all files not under version control) and rebuild numpy.

Note: this error has many possible causes, so please don't comment on
an existing issue about this - open a new one instead.

Original error was: No module named 'numpy.core._multiarray_umath'

---

编辑#5 根据@a_guest 的建议，并将我指向"ValueError: _type_ 'v' not supported" error after installing PyReadline，我删除了pyreadline，这个问题就消失了。

现在唯一剩下的问题似乎是 numpy 无法加载，可能（但不确定）由于存在两个替代 python 3.8 系统。

所以现在的问题是：Msys2: Two python installations?

Answer 1

ImportError: cannot import name 'open_code' from 'io' (unknown location) 是因为有两个不同版本的 Python 相互冲突。 python 仍然指向旧版本 3.7，但 PYTHONPATH 已更新为指向新的 3.8 版本。正如PYTHONPATH 中的the documentation 所说，它会添加到模块搜索路径中，因此会隐藏任何内置模块：

默认搜索路径取决于安装，但通常以prefix/lib/pythonversion 开头（请参阅上面的PYTHONHOME）。它总是附加到PYTHONPATH。

您可以通过创建两个不同的虚拟环境来重现该行为，然后启动一个同时让PYTHONPATH 指向另一个。下面我使用Miniconda创建了两个不同的环境，py37和py38，分别包含3.7和3.8的安装。

(py37) user@pc:~$ python --version
Python 3.7.6
(py37) user@pc:~$ PYTHONPATH=~/miniconda3/envs/py38/lib/python3.8/ python
Fatal Python error: init_sys_streams: can't initialize sys standard streams
Traceback (most recent call last):
  File "/home/user/miniconda3/envs/py38/lib/python3.8/io.py", line 54, in <module>
ImportError: cannot import name 'open_code' from 'io' (unknown location)
Aborted (core dumped)