comparison mercurial/pycompat.py @ 51310:f0e7d51bb454 stable

pycompat: fix bytestr(bytes) in Python 3.11

In Python 3.10, the `bytes` type itself does not have a `__bytes__`
attribute, but it does in 3.11. Yet `bytes(bytes)` does not give
the wished output, so we have to add an exceptional case.

The added case in the doctest reproduces the problem with Python 3.11.

Impact: error treatment in expressions such as `repo[b'invalid']` gets
broken.

51309:9b44b25dece1

    ...     def __bytes__(self):
    ...         return b'bytes'
    >>> bytestr(bytesable())
    'bytes'

    There's no implicit conversion from non-ascii str as its encoding is
    unknown:

    >>> bytestr(chr(0x80)) # doctest: +ELLIPSIS
    Traceback (most recent call last):

            pass

    def __new__(cls: Type[_Tbytestr], s: object = b'') -> _Tbytestr:
        if isinstance(s, bytestr):
            return s
        if not isinstance(
            s, (bytes, bytearray)
        ) and not builtins.hasattr(  # hasattr-py3-only
            s, u'__bytes__'
        ):
            s = str(s).encode('ascii')
        return bytes.__new__(cls, s)

    # The base class uses `int` return in py3, but the point of this class is to

51310:f0e7d51bb454

    ...     def __bytes__(self):
    ...         return b'bytes'
    >>> bytestr(bytesable())
    'bytes'

    ...unless the argument is the bytes *type* itself: it gets a
    __bytes__() method in Python 3.11, which cannot be used as in an instance
    of bytes:

    >>> bytestr(bytes)
    "<class 'bytes'>"

    There's no implicit conversion from non-ascii str as its encoding is
    unknown:

    >>> bytestr(chr(0x80)) # doctest: +ELLIPSIS
    Traceback (most recent call last):

            pass

    def __new__(cls: Type[_Tbytestr], s: object = b'') -> _Tbytestr:
        if isinstance(s, bytestr):
            return s
        if not isinstance(s, (bytes, bytearray)) and (
            isinstance(s, type)
            or not builtins.hasattr(s, u'__bytes__')  # hasattr-py3-only
        ):
            s = str(s).encode('ascii')
        return bytes.__new__(cls, s)

    # The base class uses `int` return in py3, but the point of this class is to