Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/importlib_metadata/_compat.py: 90%

1import os 

2import sys 

3import platform 

4 

5from typing import Union 

6 

7 

8__all__ = ['install', 'NullFinder'] 

9 

10 

11def install(cls): 

12 """ 

13 Class decorator for installation on sys.meta_path. 

14 

15 Adds the backport DistributionFinder to sys.meta_path and 

16 attempts to disable the finder functionality of the stdlib 

17 DistributionFinder. 

18 """ 

19 sys.meta_path.append(cls()) 

20 disable_stdlib_finder() 

21 return cls 

22 

23 

24def disable_stdlib_finder(): 

25 """ 

26 Give the backport primacy for discovering path-based distributions 

27 by monkey-patching the stdlib O_O. 

28 

29 See #91 for more background for rationale on this sketchy 

30 behavior. 

31 """ 

32 

33 def matches(finder): 

34 return getattr( 

35 finder, '__module__', None 

36 ) == '_frozen_importlib_external' and hasattr(finder, 'find_distributions') 

37 

38 for finder in filter(matches, sys.meta_path): # pragma: nocover 

39 del finder.find_distributions 

40 

41 

42class NullFinder: 

43 """ 

44 A "Finder" (aka "MetaClassFinder") that never finds any modules, 

45 but may find distributions. 

46 """ 

47 

48 @staticmethod 

49 def find_spec(*args, **kwargs): 

50 return None 

51 

52 

53def pypy_partial(val): 

54 """ 

55 Adjust for variable stacklevel on partial under PyPy. 

56 

57 Workaround for #327. 

58 """ 

59 is_pypy = platform.python_implementation() == 'PyPy' 

60 return val + is_pypy 

61 

62 

63if sys.version_info >= (3, 9): 

64 StrPath = Union[str, os.PathLike[str]] 

65else: 

66 # PathLike is only subscriptable at runtime in 3.9+ 

67 StrPath = Union[str, "os.PathLike[str]"] # pragma: no cover