I looked at #27048 and indeed it's affected by this bug, it happens to me too (I've non-ASCII symbols in %PATH%) and this my patch fixes that.


on my system without patch

> python -c "from distutils import _msvccompiler; _msvccompiler._get_vc_env('')"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "P:\Python35\lib\distutils\_msvccompiler.py", line 92, in _get_vc_env
    universal_newlines=True,
  File "P:\Python35\lib\subprocess.py", line 629, in check_output
    **kwargs).stdout
  File "P:\Python35\lib\subprocess.py", line 698, in run
    stdout, stderr = process.communicate(input, timeout=timeout)
  File "P:\Python35\lib\subprocess.py", line 1055, in communicate
    stdout = self.stdout.read()
  File "P:\Python35\lib\encodings\cp1257.py", line 23, in decode
    return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap' codec can't decode byte 0x83 in position 50: character maps to <undefined>

with my patch

> python -c "from distutils import _msvccompiler; _msvccompiler._get_vc_env('')"
>
no error