Fix annotated #123 (#126)

* added failing test case for annotated

* Fix issues with Annotated

* fix failing CI checks

* cleaned up pr

---------

Co-authored-by: Samuel Hodges <[email protected]>
Co-authored-by: Wessel <[email protected]>

plum/alias.py

@@ -28,7 +28,7 @@
 
 import typing
 from functools import wraps
-from typing import get_args
+from .plum_typing import get_args
 
 __all__ = ["activate_union_aliases", "deactivate_union_aliases", "set_union_alias"]
 

plum/plum_typing.py

@@ -0,0 +1,22 @@
+import sys
+from typing import Literal
+
+if sys.version_info < (3, 9):
+    import typing_extensions
+
+    get_type_hints = typing_extensions.get_type_hints
+    get_origin = typing_extensions.get_origin
+    get_args = typing_extensions.get_args
+
+    def is_literal(x):
+        return x == Literal and not isinstance(x, typing_extensions.Annotated)
+
+else:
+    import typing
+
+    get_type_hints = typing.get_type_hints
+    get_origin = typing.get_origin
+    get_args = typing.get_args
+
+    def is_literal(x):
+        return x == Literal

plum/signature.py

@@ -11,7 +11,8 @@
 from . import _is_bearable
 from .repr import repr_short, rich_repr
 from .type import is_faithful, resolve_type_hint
-from .util import Comparable, Missing, TypeHint, multihash, wrap_lambda
+from .plum_typing import get_type_hints
+from .util import Comparable, Missing, TypeHint, multihash, repr_short, wrap_lambda
 
 __all__ = ["Signature", "append_default_args"]
 
@@ -285,7 +286,7 @@ def resolve_pep563(f: Callable):
         beartype_resolve_pep563(f)  # This mutates `f`.
         # Override the `__annotations__` attribute, since `resolve_pep563` modifies
         # `f` too.
-        for k, v in typing.get_type_hints(f).items():
+        for k, v in get_type_hints(f, include_extras=True).items():
             f.__annotations__[k] = v
 
 

plum/type.py

@@ -2,7 +2,9 @@
 import sys
 import typing
 import warnings
-from typing import Literal, get_args, get_origin
+from .plum_typing import get_args, get_origin, is_literal
+
+from beartype.vale._core._valecore import BeartypeValidator
 
 try:  # pragma: specific no cover 3.8 3.9
     from types import UnionType
@@ -128,7 +130,8 @@ def _is_hint(x):
         return x.__module__ in {
             "types",  # E.g., `tuple[int]`
             "typing",
-            "collections.abc",  # E.g., `Callable`
+            "collections.abc",  # E.g., `Callable`,
+            "typing_extensions",
         }
     except AttributeError:
         return False
@@ -183,7 +186,7 @@ def resolve_type_hint(x):
                 return y
             else:
                 # Do not resolve the arguments for `Literal`s.
-                if origin != Literal:
+                if not is_literal(origin):
                     args = resolve_type_hint(args)
                 try:
                     return origin[args]
@@ -218,7 +221,8 @@ def resolve_type_hint(x):
             return resolve_type_hint(x.resolve())
         else:
             return x
-
+    elif isinstance(x, BeartypeValidator):
+        return x
     else:
         warnings.warn(
             f"Could not resolve the type hint of `{x}`. "

tests/advanced/test_annotated.py

@@ -0,0 +1,29 @@
+import sys
+
+if sys.version_info < (3, 9):
+    from typing_extensions import Annotated
+else:
+    from typing import Annotated
+
+import pytest
+from beartype.vale import Is
+
+from plum import Dispatcher, NotFoundLookupError
+
+
+def test_simple_annotated():
+    dispatch = Dispatcher()
+
+    positive_int = Annotated[int, Is[lambda value: value > 0]]
+
+    @dispatch
+    def f(x: positive_int):
+        return x
+
+    assert f(1) == 1
+
+    with pytest.raises(NotFoundLookupError):
+        f("my string")
+
+    with pytest.raises(NotFoundLookupError):
+        f(-1)