Source code for phantom.negated

"""
This module provides a single type: :py:class:`SequenceNotStr`. This type is equivalent
to :py:class:`typing.Sequence` except it excludes values of type :py:class:`str` and
:py:class:`bytes` from the set of valid instances. This can be useful when you want to
eliminate the easy mistake of forgetting to wrap a string value in a containing
sequence.
"""

from __future__ import annotations

from collections.abc import Sequence
from typing import Generic
from typing import TypeVar

from typing_extensions import get_args

from . import Phantom
from . import _hypothesis
from .predicates import boolean
from .predicates.generic import of_type

__all__ = ("SequenceNotStr",)

T = TypeVar("T")




class SequenceNotStr(
    Sequence[T],
    Phantom,
    Generic[T],
    # Note: We don't eliminate mutable types here like in PhantomSized. This is because
    # the property of not being a str cannot change by mutation, so this specific
    # phantom type is safe to use with mutable types.
    predicate=boolean.negate(of_type((str, bytes))),
):
    @classmethod
    def __register_strategy__(cls) -> _hypothesis.HypothesisStrategy:
        from hypothesis.strategies import from_type
        from hypothesis.strategies import tuples

        def create_strategy(
            type_: type[T],
        ) -> _hypothesis.SearchStrategy[tuple[T, ...]] | None:
            (inner_type,) = get_args(type_)
            return tuples(from_type(inner_type))

        return create_strategy