feat: support PEP604 syntax str | None

[nh13]

Fixes #89

[codecov]

Codecov Report

Attention: Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 88.99%. Comparing base (57f13cc) to head (07a797c).

Files	Patch %	Lines
fgpyo/util/types.py	86.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #168      +/-   ##
==========================================
- Coverage   89.02%   88.99%   -0.04%     
==========================================
  Files          17       17              
  Lines        2005     2017      +12     
  Branches      437      439       +2     
==========================================
+ Hits         1785     1795      +10     
- Misses        144      145       +1     
- Partials       76       77       +1     

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[tfenne]

I don't think I know enough to review this well, so will rely on @msto.

[nh13]

@msto bump

[msto]

issue GenericAlias should be included as a valid type annotation type. Also add from types import GenericAlias above

Suggested change

	TypeAnnotation: TypeAlias = Union[type, typing._GenericAlias, UnionType] # type: ignore[name-defined]
	TypeAnnotation: TypeAlias = Union[type, typing._GenericAlias, UnionType,
	types.GenericAlias] # type: ignore[name-defined]

[msto]

Suggested change

	"""Check if a type is `Optional`.
	An optional type may be declared using three syntaxes: `Optional[T]`, `Union[T, None]`, or `T |
	None`. All of these syntaxes is supported by this function.
	Args:
	dtype: A type.
	Returns:
	True if the type is a union type with exactly two elements, one of which is `None`.
	False otherwise.
	Raises:
	TypeError: If the input is not a valid `TypeAnnotation` type (see above).
	"""
	"""
	Check if a type is `Optional`.
	An optional type may be declared using three syntaxes: `Optional[T]`, `Union[T, None]`, or `T |
	None`. All of these syntaxes are supported by this function.
	Args:
	dtype: A type.
	Returns:
	True if the type is a union type with exactly two elements, one of which is `None`.
	False otherwise.
	Raises:
	TypeError: If the input is not a valid `TypeAnnotation` type.
	Type annotations may be any of `type`, `types.UnionType`, `types.GenericAlias`, or `typing._GenericAlias`.
	"""

[msto]

issue as above, we should include types.GenericAlias

Suggested change

	TYPE_ANNOTATION_TYPES = (type, typing._GenericAlias, UnionType) # type: ignore[attr-defined]
	TYPE_ANNOTATION_TYPES = (type, typing._GenericAlias, UnionType, GenericAlias) # type: ignore[attr-defined]

[msto]

nit I think it's more in line with our convention to import these functions instead of referencing them as module attributes

Suggested change

	origin = typing.get_origin(dtype)
	args = typing.get_args(dtype)
	origin = get_origin(dtype)
	args = get_args(dtype)

[msto]

suggestion Save a couple lines?

Suggested change

	assert not types._is_optional(str)
	if sys.version_info >= (3, 10):
	def test_is_optional_python_310() -> None:
	assert types._is_optional(str | None)
	assert not types._is_optional(str)
	if sys.version_info >= (3, 10):
	assert types._is_optional(str | None)

[msto]

suggestion Test a couple union types that don't meet our criteria

Suggested change

	assert types._is_optional(Optional[str])
	assert not types._is_optional(str)
	assert types._is_optional(Optional[str])
	assert not types._is_optional(Union[str, int])
	assert not types._is_optional(Union[str, int, None])
	assert not types._is_optional(str)

[msto]

NB: for brevity (and to catch multiple failures in a single pytest invocation), you could use pytest.mark.parameterize over the tested types