Python Gotchas
Python Gotchas#
Do Not Name Modules after Python Built-in#
You may get an error like this:
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 "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/unittest/__init__.py", line 59, in <module>
from .case import (TestCase, FunctionTestCase, SkipTest, skip, skipIf,
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/unittest/case.py", line 6, 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'
It will then say:
Exception ignored in: <module 'threading' from '/my/python/project/threading/__init__.py'>
AttributeError: module 'threading' has no attribute '_shutdown'
This means the standard library is using my local version of threading.
It is a naming conflict.
You probably have a folder with a __init__.py inside it that is called threading/ or you have a file called threading.
Generally, its not a good idea to name python scripts after builtin scripts.
You can get a list of keywords and builtins with:
import keyword
>>> keyword.kwlist
['False',
'None',
'True',
'__peg_parser__',
'and',
'as',
'assert',
'async',
'await',
'break',
'class',
'continue',
'def',
'del',
'elif',
'else',
'except',
'finally',
'for',
'from',
'global',
'if',
'import',
'in',
'is',
'lambda',
'nonlocal',
'not',
'or',
'pass',
'raise',
'return',
'try',
'while',
'with',
'yield']
import builtins
dir(builtins)
['ArithmeticError',
'AssertionError',
'AttributeError',
'BaseException',
'BlockingIOError',
'BrokenPipeError',
'BufferError',
'BytesWarning',
'ChildProcessError',
'ConnectionAbortedError',
'ConnectionError',
'ConnectionRefusedError',
'ConnectionResetError',
'DeprecationWarning',
'EOFError',
'Ellipsis',
'EnvironmentError',
'Exception',
'False',
'FileExistsError',
'FileNotFoundError',
'FloatingPointError',
'FutureWarning',
'GeneratorExit',
'IOError',
'ImportError',
'ImportWarning',
'IndentationError',
'IndexError',
'InterruptedError',
'IsADirectoryError',
'KeyError',
'KeyboardInterrupt',
'LookupError',
'MemoryError',
'ModuleNotFoundError',
'NameError',
'None',
'NotADirectoryError',
'NotImplemented',
'NotImplementedError',
'OSError',
'OverflowError',
'PendingDeprecationWarning',
'PermissionError',
'ProcessLookupError',
'RecursionError',
'ReferenceError',
'ResourceWarning',
'RuntimeError',
'RuntimeWarning',
'StopAsyncIteration',
'StopIteration',
'SyntaxError',
'SyntaxWarning',
'SystemError',
'SystemExit',
'TabError',
'TimeoutError',
'True',
'TypeError',
'UnboundLocalError',
'UnicodeDecodeError',
'UnicodeEncodeError',
'UnicodeError',
'UnicodeTranslateError',
'UnicodeWarning',
'UserWarning',
'ValueError',
'Warning',
'ZeroDivisionError',
'__IPYTHON__',
'__build_class__',
'__debug__',
'__doc__',
'__import__',
'__loader__',
'__name__',
'__package__',
'__spec__',
'abs',
'all',
'any',
'ascii',
'bin',
'bool',
'breakpoint',
'bytearray',
'bytes',
'callable',
'chr',
'classmethod',
'compile',
'complex',
'copyright',
'credits',
'delattr',
'dict',
'dir',
'display',
'divmod',
'enumerate',
'eval',
'exec',
'filter',
'float',
'format',
'frozenset',
'get_ipython',
'getattr',
'globals',
'hasattr',
'hash',
'help',
'hex',
'id',
'input',
'int',
'isinstance',
'issubclass',
'iter',
'len',
'license',
'list',
'locals',
'map',
'max',
'memoryview',
'min',
'next',
'object',
'oct',
'open',
'ord',
'pow',
'print',
'property',
'range',
'repr',
'reversed',
'round',
'set',
'setattr',
'slice',
'sorted',
'staticmethod',
'str',
'sum',
'super',
'tuple',
'type',
'vars',
'zip']
or anything in the Lib folder of python