为什么 Jupyter notebook 打不开内核？

Question

我最近在一台新计算机上安装了 Jupyter，在尝试使用和不使用 virtualenv 后，我收到以下与线程模块相关的错误。此错误会阻止笔记本 (1) 打开或 (2) 启动内核。

打开python -m notebook 时出错。笔记本无法成功打开。

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/runpy.py", line 183, in _run_module_as_main
    mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/runpy.py", line 142, in _get_module_details
    return _get_module_details(pkg_main_name, error)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/runpy.py", line 109, in _get_module_details
    __import__(pkg_name)
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/notebook/__init__.py", line 25, in <module>
    from .nbextensions import install_nbextension
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/notebook/nbextensions.py", line 31, in <module>
    from .config_manager import BaseJSONConfigManager
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/notebook/config_manager.py", line 15, in <module>
    from traitlets.config import LoggingConfigurable
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/traitlets/config/__init__.py", line 6, in <module>
    from .application import *
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/traitlets/config/application.py", line 11, in <module>
    import logging
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/logging/__init__.py", line 210, in <module>
    _lock = threading.RLock()
AttributeError: module 'threading' has no attribute 'RLock'
Exception ignored in: <module 'threading' from '/Users/me/Downloads/threading.py'>
AttributeError: module 'threading' has no attribute '_shutdown'

切换目录后出错，成功打开notebook，尝试连接内核

[I 09:32:05.828 NotebookApp] KernelRestarter: restarting kernel (3/5), new random ports
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/ipykernel_launcher.py", line 15, in <module>
    from ipykernel import kernelapp as app
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/ipykernel/__init__.py", line 2, in <module>
    from .connect import *
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/ipykernel/connect.py", line 13, in <module>
    from IPython.core.profiledir import ProfileDir
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/IPython/__init__.py", line 54, in <module>
    from .core.application import Application
  File "/Users/me/Documents/Code/Python/Environments/Jupyter/lib/python3.7/site-packages/IPython/core/application.py", line 18, in <module>
    import logging
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/logging/__init__.py", line 210, in <module>
    _lock = threading.RLock()
AttributeError: module 'threading' has no attribute 'RLock'
Exception ignored in: <module 'threading' from '/Users/me/Downloads/threading.py'>
AttributeError: module 'threading' has no attribute '_shutdown'

由于线程是一个内置模块，我无法更新它。同样，使用正常的site-packages 安装和干净的virtualenv 安装，这个结果是相同的。

Answer 1

我发现这个错误是因为我的主目录的子目录中存在一个名为threading.py的文件（与内置模块无关）。如果我从当前目录下的目录树中任何文件所在的任何目录启动笔记本，我会收到此错误。

解决方法是在与内置threading不存在命名冲突的目录中启动笔记本。

奇怪的是，如果我 import threading 在发生故障的同一目录中的 Python shell 中运行 dir(threading)，它会选择正确的包。为什么 Jupyter 会以不同的方式处理这个问题？