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gh-85668: Add typing.evaluate_type() function #150363

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18 changes: 18 additions & 0 deletions Doc/library/typing.rst
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Expand Up @@ -3727,6 +3727,24 @@ Introspection helpers

.. versionadded:: 3.14

.. function:: evaluate_type(type_hint, *, owner=None, globals=None, locals=None, type_params=None, format=annotationlib.Format.VALUE)

Evaluate a :term:`type hint`, by resolving any forward references nested
within the type hint.

This is similar to calling :func:`evaluate_forward_ref`, but unlike that
method, :func:`evaluate_type` also supports arbitrary type hints.

See the documentation for :meth:`annotationlib.ForwardRef.evaluate` for
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@Viicos Viicos May 24, 2026

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We can also properly document the behavior of each argument here, but this will introduce some repetition..

the meaning of the *owner*, *globals*, *locals*, *type_params*, and *format* parameters.

.. caution::

This function may execute arbitrary code contained the type hint.
See :ref:`annotationlib-security` for more information.

.. versionadded:: next

.. data:: NoDefault

A sentinel object used to indicate that a type parameter has no default
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18 changes: 18 additions & 0 deletions Lib/typing.py
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Expand Up @@ -1051,6 +1051,24 @@ def evaluate_forward_ref(
)


def evaluate_type(
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@Viicos Viicos May 24, 2026

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Should we allow plain strings to be passed, by using _make_forward_ref()? If so, what should we use for is_argument and is_class? I'd suggest we can infer the object type from owner, and if globals/locals/type params are manually provided instead, we pass is_argument=False, is_class=True as we can't assume anything on the owner and so we allow any type qualifier.

type_hint,
*,
owner=None,
globalns=None,
localns=None,
type_params=None,
format=annotationlib.Format.VALUE,
):
"""Evaluate a type hint, by resolving any forward references.

This is similar to the evaluate_forward_ref() method, but unlike that method,
evaluate_type() also supports arbitrary type hints.
"""

return _eval_type(type_hint, owner=owner, globalns=globalns, localns=localns, type_params=type_params, format=format)


def _is_unpacked_typevartuple(x: Any) -> bool:
# Need to check 'is True' here
# See: https://github.com/python/cpython/issues/137706
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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2026-05-24-21-20-19.gh-issue-85668.KwCVdi.rst
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@@ -0,0 +1 @@
Add :func:`typing.evaluate_type` function.
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