core: more tests and proper support for PEP 695 type parameter syntax

Author: karlicoss

src/cachew/__init__.py

@@ -14,7 +14,6 @@
     TYPE_CHECKING,
     Any,
     Literal,
-    TypeAliasType,
     cast,
     get_args,
     get_origin,
@@ -46,6 +45,7 @@ def orjson_dumps(*args, **kwargs):  # type: ignore[misc]
 from .utils import (
     CachewException,
     TypeNotSupported,
+    resolve_type_parameters,
 )
 
 # in case of changes in the way cachew stores data, this should be changed to discard old caches
@@ -119,15 +119,15 @@ def infer_return_type(func) -> Failure | Inferred:
     ...     return None if len(s) == 0 else s[0]
     >>> kind, opt = infer_return_type(first_character)
     >>> # in 3.8, Optional[str] is printed as Union[str, None], so need to hack around this
-    >>> (kind, opt is Optional[str])
+    >>> (kind, opt == Optional[str])
     ('single', True)
 
     # tuple is an iterable.. but presumably should be treated as a single value
     >>> from typing import Tuple
     >>> def a_tuple() -> Tuple[int, str]:
     ...     return (123, 'hi')
     >>> infer_return_type(a_tuple)
-    ('single', typing.Tuple[int, str])
+    ('single', tuple[int, str])
 
     >>> from typing import Collection, NamedTuple
     >>> class Person(NamedTuple):
@@ -169,14 +169,14 @@ def infer_return_type(func) -> Failure | Inferred:
     ...     yield 1
     ...     yield 'aaa'
     >>> infer_return_type(iterator_str_int)
-    ('multiple', Str | Int)
+    ('multiple', str | int)
 
     # a bit of an edge case
     >>> from typing import Tuple
     >>> def empty_tuple() -> Iterator[Tuple[()]]:
     ...     yield ()
     >>> infer_return_type(empty_tuple)
-    ('multiple', typing.Tuple[()])
+    ('multiple', tuple[()])
 
     ... # doctest: +ELLIPSIS
 
@@ -196,7 +196,7 @@ def infer_return_type(func) -> Failure | Inferred:
     >>> def unsupported_list() -> List[Custom]:
     ...     return [Custom()]
     >>> infer_return_type(unsupported_list)
-    "can't infer type from typing.List[cachew.Custom]: can't cache <class 'cachew.Custom'>"
+    "can't infer type from list[cachew.Custom]: can't cache <class 'cachew.Custom'>"
     """
     try:
         hints = get_type_hints(func)
@@ -208,9 +208,7 @@ def infer_return_type(func) -> Failure | Inferred:
     if rtype is None:
         return f"no return type annotation on {func}"
 
-    if isinstance(rtype, TypeAliasType):
-        # handle 'type ... = ...' aliases
-        rtype = rtype.__value__
+    rtype = resolve_type_parameters(rtype)
 
     def bail(reason: str) -> str:
         return f"can't infer type from {rtype}: " + reason

src/cachew/marshall/cachew.py

@@ -14,15 +14,14 @@
     NamedTuple,
     Optional,
     Tuple,
-    TypeAliasType,
     Union,
     get_args,
     get_origin,
     get_type_hints,
 )
 from zoneinfo import ZoneInfo
 
-from ..utils import TypeNotSupported, is_namedtuple
+from ..utils import TypeNotSupported, is_namedtuple, resolve_type_parameters
 from .common import AbstractMarshall, Json
 
 
@@ -290,13 +289,11 @@ def load(self, dct: str):
 
 
 def build_schema(Type) -> Schema:
-    if isinstance(Type, TypeAliasType):
-        # handle 'type ... = ...' aliases
-        Type = Type.__value__
-
     # just to avoid confusion in case of weirdness with stringish type annotations
     assert not isinstance(Type, str), Type
 
+    Type = resolve_type_parameters(Type)
+
     ptype = PRIMITIVES.get(Type)
     if ptype is not None:
         return SPrimitive(type=ptype)
@@ -618,6 +615,3 @@ class NotSupported:
         helper([1, 2, 3], list[int] | list[Exception])
     with pytest.raises(TypeNotSupported, match=r".*runtime union arguments are not unique"):
         helper([1, 2, 3], list[Exception] | list[int])
-
-
-# TODO test type aliases and such??

src/cachew/tests/test_cachew.py

@@ -1461,3 +1461,15 @@ def fun() -> IteratorInt:
 
     assert list(fun()) == [123]
     assert list(fun()) == [123]
+
+
+def test_type_alias_generic(tmp_path: Path) -> None:
+    type Res[T] = T | Exception
+    type IntRes = Res[int]
+
+    @cachew(tmp_path)
+    def fun() -> Iterator[IntRes]:
+        yield 123
+
+    assert list(fun()) == [123]
+    assert list(fun()) == [123]

src/cachew/tests/test_future_annotations.py

@@ -104,15 +104,18 @@ def test_future_annotations(
 '''
 
     _TEST = '''
-type T = int
+
+type Identity[T] = T
+I = int
+type S = Identity[str]
 
 @cachew(td)
-def fun() -> list[T]:
+def fun() -> list[I | S]:
     print("called")
-    return [1, 2]
+    return [1, "2"]
 
-assert list(fun()) == [1, 2]
-assert list(fun()) == [1, 2]
+assert list(fun()) == [1, "2"]
+assert list(fun()) == [1, "2"]
 '''
 
     if use_future_annotations: