pathlib __truediv__ returns the "self" type #553

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1. gvanrossum commented on Sep 17, 2016

   

   gvanrossum

   on Sep 17, 2016

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   Yes, this is currently a problem. We first need to solve python/mypy#1212 and then it should be easy. See also python/peps#89
2. dckc commented on Sep 17, 2016

   

   dckc

   on Sep 17, 2016

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   I found a work-around:

   import pathlib as pl
   from typing import TypeVar, Generic, Union
   
   
   Self = TypeVar('Self')
   
   
   class PosixPathFix(pl.PosixPath, Generic[Self]):
       def __truediv__(self, key: Union [str, pl.PurePath]) -> Self:   # type: ignore
           return super(PosixPathFix, self).__truediv__(key)  # type: ignore
   
   
   class MyPath(PosixPathFix):
       def parity(self):
           return len(str(self)) % 2
   
   
   root = MyPath('/')
   print(root, root.parity())
   child = root / 'there'
   print(child, child.parity())
3. gvanrossum commented on Sep 17, 2016

   

   gvanrossum

   on Sep 17, 2016 via email

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   Yeah, until we have SelfType, type ignore is your friend... :-/

   …

   --Guido (mobile)
4. gvanrossum

   closed this as completedin #658on Nov 4, 2016