Update some type inference code

Author: Zac-HD

hypothesis-python/src/hypothesis/strategies/_internal/core.py

@@ -25,7 +25,7 @@
 from functools import reduce
 from inspect import Parameter, Signature, isabstract, isclass
 from re import Pattern
-from types import FunctionType
+from types import FunctionType, GenericAlias
 from typing import (
     Any,
     AnyStr,
@@ -1326,6 +1326,13 @@ def from_type_guarded(thing):
             strategy = as_strategy(types._global_type_lookup[thing], thing)
             if strategy is not NotImplemented:
                 return strategy
+        elif (
+            isinstance(thing, GenericAlias)
+            and (to := get_origin(thing)) in types._global_type_lookup
+        ):
+            strategy = as_strategy(types._global_type_lookup[to], thing)
+            if strategy is not NotImplemented:
+                return strategy
     except TypeError:  # pragma: no cover
         # This was originally due to a bizarre divergence in behaviour on Python 3.9.0:
         # typing.Callable[[], foo] has __args__ = (foo,) but collections.abc.Callable

hypothesis-python/src/hypothesis/strategies/_internal/types.py

@@ -28,10 +28,11 @@
 import uuid
 import warnings
 import zoneinfo
+from collections.abc import Iterator
 from functools import partial
 from pathlib import PurePath
 from types import FunctionType
-from typing import TYPE_CHECKING, Any, Iterator, Tuple, get_args, get_origin
+from typing import TYPE_CHECKING, Any, get_args, get_origin
 
 from hypothesis import strategies as st
 from hypothesis.errors import HypothesisWarning, InvalidArgument, ResolutionFailed
@@ -339,7 +340,7 @@ def get_constraints_filter_map():
     return {}  # pragma: no cover
 
 
-def _get_constraints(args: Tuple[Any, ...]) -> Iterator["at.BaseMetadata"]:
+def _get_constraints(args: tuple[Any, ...]) -> Iterator["at.BaseMetadata"]:
     at = sys.modules.get("annotated_types")
     for arg in args:
         if at and isinstance(arg, at.BaseMetadata):
@@ -619,7 +620,7 @@ def _networks(bits):
 # exposed for it, and NotImplemented itself is typed as Any so that it can be
 # returned without being listed in a function signature:
 # https://github.com/python/mypy/issues/6710#issuecomment-485580032
-_global_type_lookup: typing.Dict[
+_global_type_lookup: dict[
     type, typing.Union[st.SearchStrategy, typing.Callable[[type], st.SearchStrategy]]
 ] = {
     type(None): st.none(),
@@ -726,8 +727,8 @@ def _networks(bits):
     _global_type_lookup[builtins.sequenceiterator] = st.builds(iter, st.tuples())  # type: ignore
 
 
-_global_type_lookup[type] = st.sampled_from(
-    [type(None), *sorted(_global_type_lookup, key=str)]
+_fallback_type_strategy = st.sampled_from(
+    sorted(_global_type_lookup, key=type_sorting_key)
 )
 # subclass of MutableMapping, and so we resolve to a union which
 # includes this... but we don't actually ever want to build one.
@@ -803,15 +804,15 @@ def _networks(bits):
 # installed. To avoid the performance hit of importing anything here, we defer
 # it until the method is called the first time, at which point we replace the
 # entry in the lookup table with the direct call.
-def _from_numpy_type(thing: typing.Type) -> typing.Optional[st.SearchStrategy]:
+def _from_numpy_type(thing: type) -> typing.Optional[st.SearchStrategy]:
     from hypothesis.extra.numpy import _from_type
 
     _global_extra_lookup["numpy"] = _from_type
     return _from_type(thing)
 
 
-_global_extra_lookup: typing.Dict[
-    str, typing.Callable[[typing.Type], typing.Optional[st.SearchStrategy]]
+_global_extra_lookup: dict[
+    str, typing.Callable[[type], typing.Optional[st.SearchStrategy]]
 ] = {
     "numpy": _from_numpy_type,
 }
@@ -839,26 +840,30 @@ def really_inner(thing):
                 return fallback
             return func(thing)
 
+        _global_type_lookup[type_] = really_inner
         _global_type_lookup[get_origin(type_) or type_] = really_inner
         return really_inner
 
     return inner
 
 
-@register(typing.Type)
+@register(type)
+@register("Type")
 @register("Type", module=typing_extensions)
 def resolve_Type(thing):
     if getattr(thing, "__args__", None) is None:
         return st.just(type)
+    elif get_args(thing) == ():  # pragma: no cover
+        return _fallback_type_strategy
     args = (thing.__args__[0],)
     if is_a_union(args[0]):
         args = args[0].__args__
     # Duplicate check from from_type here - only paying when needed.
     args = list(args)
     for i, a in enumerate(args):
-        if type(a) == typing.ForwardRef:
+        if type(a) in (typing.ForwardRef, str):
             try:
-                args[i] = getattr(builtins, a.__forward_arg__)
+                args[i] = getattr(builtins, getattr(a, "__forward_arg__", a))
             except AttributeError:
                 raise ResolutionFailed(
                     f"Cannot find the type referenced by {thing} - try using "
@@ -867,12 +872,12 @@ def resolve_Type(thing):
     return st.sampled_from(sorted(args, key=type_sorting_key))
 
 
-@register(typing.List, st.builds(list))
+@register("List", st.builds(list))
 def resolve_List(thing):
     return st.lists(st.from_type(thing.__args__[0]))
 
 
-@register(typing.Tuple, st.builds(tuple))
+@register("Tuple", st.builds(tuple))
 def resolve_Tuple(thing):
     elem_types = getattr(thing, "__args__", None) or ()
     if len(elem_types) == 2 and elem_types[-1] is Ellipsis:
@@ -906,27 +911,28 @@ def _from_hashable_type(type_):
         return st.from_type(type_).filter(_can_hash)
 
 
-@register(typing.Set, st.builds(set))
+@register("Set", st.builds(set))
 @register(typing.MutableSet, st.builds(set))
 def resolve_Set(thing):
     return st.sets(_from_hashable_type(thing.__args__[0]))
 
 
-@register(typing.FrozenSet, st.builds(frozenset))
+@register("FrozenSet", st.builds(frozenset))
 def resolve_FrozenSet(thing):
     return st.frozensets(_from_hashable_type(thing.__args__[0]))
 
 
-@register(typing.Dict, st.builds(dict))
+@register("Dict", st.builds(dict))
 def resolve_Dict(thing):
     # If thing is a Collection instance, we need to fill in the values
-    keys_vals = thing.__args__ * 2
+    keys, vals, *_ = thing.__args__ * 2
     return st.dictionaries(
-        _from_hashable_type(keys_vals[0]), st.from_type(keys_vals[1])
+        _from_hashable_type(keys),
+        st.none() if vals is None else st.from_type(vals),
     )
 
 
-@register(typing.DefaultDict, st.builds(collections.defaultdict))
+@register("DefaultDict", st.builds(collections.defaultdict))
 @register("DefaultDict", st.builds(collections.defaultdict), module=typing_extensions)
 def resolve_DefaultDict(thing):
     return resolve_Dict(thing).map(lambda d: collections.defaultdict(None, d))
@@ -988,9 +994,9 @@ def resolve_Pattern(thing):
     return st.just(re.compile(thing.__args__[0]()))
 
 
-@register(  # pragma: no branch  # coverage does not see lambda->exit branch
+@register(
     typing.Match,
-    st.text().map(lambda c: re.match(".", c, flags=re.DOTALL)).filter(bool),
+    st.text().map(partial(re.match, ".", flags=re.DOTALL)).filter(bool),
 )
 def resolve_Match(thing):
     if thing.__args__[0] == bytes:

hypothesis-python/tests/cover/test_lookup.py

@@ -66,6 +66,12 @@
     ),
     key=str,
 )
+_Type = getattr(typing, "Type", None)
+_List = getattr(typing, "List", None)
+_Dict = getattr(typing, "Dict", None)
+_Set = getattr(typing, "Set", None)
+_FrozenSet = getattr(typing, "FrozenSet", None)
+_Tuple = getattr(typing, "Tuple", None)
 
 
 @pytest.mark.parametrize("typ", generics, ids=repr)
@@ -104,10 +110,13 @@ def test_specialised_scalar_types(data, typ, instance_of):
 
 
 def test_typing_Type_int():
-    assert_simple_property(from_type(typing.Type[int]), lambda x: x is int)
+    for t in (type[int], type["int"], _Type[int], _Type["int"]):
+        assert_simple_property(from_type(t), lambda x: x is int)
 
 
-@given(from_type(typing.Type[typing.Union[str, list]]))
+@given(
+    from_type(type[typing.Union[str, list]]) | from_type(_Type[typing.Union[str, list]])
+)
 def test_typing_Type_Union(ex):
     assert ex in (str, list)
 
@@ -143,15 +152,21 @@ class Elem:
 @pytest.mark.parametrize(
     "typ,coll_type",
     [
-        (typing.Set[Elem], set),
-        (typing.FrozenSet[Elem], frozenset),
-        (typing.Dict[Elem, None], dict),
+        (_Set[Elem], set),
+        (_FrozenSet[Elem], frozenset),
+        (_Dict[Elem, None], dict),
+        (set[Elem], set),
+        (frozenset[Elem], frozenset),
+        # (dict[Elem, None], dict),  # FIXME this should work
         (typing.DefaultDict[Elem, None], collections.defaultdict),
         (typing.KeysView[Elem], type({}.keys())),
         (typing.ValuesView[Elem], type({}.values())),
-        (typing.List[Elem], list),
-        (typing.Tuple[Elem], tuple),
-        (typing.Tuple[Elem, ...], tuple),
+        (_List[Elem], list),
+        (_Tuple[Elem], tuple),
+        (_Tuple[Elem, ...], tuple),
+        (list[Elem], list),
+        (tuple[Elem], tuple),
+        (tuple[Elem, ...], tuple),
         (typing.Iterator[Elem], typing.Iterator),
         (typing.Sequence[Elem], typing.Sequence),
         (typing.Iterable[Elem], typing.Iterable),
@@ -226,23 +241,24 @@ def test_Optional_minimises_to_None():
     assert minimal(from_type(typing.Optional[int]), lambda ex: True) is None
 
 
-@pytest.mark.parametrize("n", range(10))
-def test_variable_length_tuples(n):
-    type_ = typing.Tuple[int, ...]
+@pytest.mark.parametrize("n", [0, 1, 5])
+@pytest.mark.parametrize("t", [tuple, _Tuple])
+def test_variable_length_tuples(t, n):
+    type_ = t[int, ...]
     check_can_generate_examples(from_type(type_).filter(lambda ex: len(ex) == n))
 
 
 def test_lookup_overrides_defaults():
     sentinel = object()
     with temp_registered(int, st.just(sentinel)):
 
-        @given(from_type(typing.List[int]))
+        @given(from_type(list[int]))
         def inner_1(ex):
             assert all(elem is sentinel for elem in ex)
 
         inner_1()
 
-    @given(from_type(typing.List[int]))
+    @given(from_type(list[int]))
     def inner_2(ex):
         assert all(isinstance(elem, int) for elem in ex)
 
@@ -253,7 +269,7 @@ def test_register_generic_typing_strats():
     # I don't expect anyone to do this, but good to check it works as expected
     with temp_registered(
         typing.Sequence,
-        types._global_type_lookup[typing.get_origin(typing.Set) or typing.Set],
+        types._global_type_lookup[set],
     ):
         # We register sets for the abstract sequence type, which masks subtypes
         # from supertype resolution but not direct resolution
@@ -264,9 +280,7 @@ def test_register_generic_typing_strats():
             from_type(typing.Container[int]),
             lambda ex: not isinstance(ex, typing.Sequence),
         )
-        assert_all_examples(
-            from_type(typing.List[int]), lambda ex: isinstance(ex, list)
-        )
+        assert_all_examples(from_type(list[int]), lambda ex: isinstance(ex, list))
 
 
 def if_available(name):
@@ -587,7 +601,7 @@ def test_override_args_for_namedtuple(thing):
     assert thing.a is None
 
 
-@pytest.mark.parametrize("thing", [typing.Optional, typing.List, typing.Type])
+@pytest.mark.parametrize("thing", [typing.Optional, list, type, _List, _Type])
 def test_cannot_resolve_bare_forward_reference(thing):
     t = thing["ConcreteFoo"]
     with pytest.raises(InvalidArgument):
@@ -740,7 +754,7 @@ def test_resolving_recursive_type_with_registered_constraint_not_none():
         find_any(s, lambda s: s.next_node is not None)
 
 
-@given(from_type(typing.Tuple[()]))
+@given(from_type(tuple[()]) | from_type(_Tuple[()]))
 def test_resolves_empty_Tuple_issue_1583_regression(ex):
     # See e.g. https://github.com/python/mypy/commit/71332d58
     assert ex == ()
@@ -805,11 +819,17 @@ def test_cannot_resolve_abstract_class_with_no_concrete_subclass(instance):
 
 
 @fails_with(ResolutionFailed)
-@given(st.from_type(typing.Type["ConcreteFoo"]))
+@given(st.from_type(type["ConcreteFoo"]))
 def test_cannot_resolve_type_with_forwardref(instance):
     raise AssertionError("test body unreachable as strategy cannot resolve")
 
 
+@fails_with(ResolutionFailed)
+@given(st.from_type(_Type["ConcreteFoo"]))
+def test_cannot_resolve_type_with_forwardref_old(instance):
+    raise AssertionError("test body unreachable as strategy cannot resolve")
+
+
 @pytest.mark.parametrize("typ", [typing.Hashable, typing.Sized])
 @given(data=st.data())
 def test_inference_on_generic_collections_abc_aliases(typ, data):
@@ -938,9 +958,12 @@ def test_timezone_lookup(type_):
 @pytest.mark.parametrize(
     "typ",
     [
-        typing.Set[typing.Hashable],
-        typing.FrozenSet[typing.Hashable],
-        typing.Dict[typing.Hashable, int],
+        _Set[typing.Hashable],
+        _FrozenSet[typing.Hashable],
+        _Dict[typing.Hashable, int],
+        set[typing.Hashable],
+        frozenset[typing.Hashable],
+        dict[typing.Hashable, int],
     ],
 )
 @settings(suppress_health_check=[HealthCheck.data_too_large])
@@ -973,7 +996,8 @@ def __init__(self, value=-1) -> None:
     "typ,repr_",
     [
         (int, "integers()"),
-        (typing.List[str], "lists(text())"),
+        (list[str], "lists(text())"),
+        (_List[str], "lists(text())"),
         ("not a type", "from_type('not a type')"),
         (random.Random, "randoms()"),
         (_EmptyClass, "from_type(tests.cover.test_lookup._EmptyClass)"),
@@ -1123,15 +1147,22 @@ def test_resolves_forwardrefs_to_builtin_types(t, data):
 
 @pytest.mark.parametrize("t", BUILTIN_TYPES, ids=lambda t: t.__name__)
 def test_resolves_type_of_builtin_types(t):
-    assert_simple_property(st.from_type(typing.Type[t.__name__]), lambda v: v is t)
+    assert_simple_property(st.from_type(type[t.__name__]), lambda v: v is t)
 
 
-@given(st.from_type(typing.Type[typing.Union["str", "int"]]))
+@given(
+    st.from_type(type[typing.Union["str", "int"]])
+    | st.from_type(_Type[typing.Union["str", "int"]])
+)
 def test_resolves_type_of_union_of_forwardrefs_to_builtins(x):
     assert x in (str, int)
 
 
-@pytest.mark.parametrize("type_", [typing.List[int], typing.Optional[int]])
+@pytest.mark.parametrize(
+    # Old-style `List` because `list[int]() == list()`, so no need for the hint.
+    "type_",
+    [getattr(typing, "List", None)[int], typing.Optional[int]],
+)
 def test_builds_suggests_from_type(type_):
     with pytest.raises(
         InvalidArgument, match=re.escape(f"try using from_type({type_!r})")

tooling/src/hypothesistooling/__main__.py

@@ -208,9 +208,7 @@ def warn(msg):
 
     codespell("--write-changes", *files_to_format, *doc_files_to_format)
     pip_tool("ruff", "check", "--fix-only", ".")
-    pip_tool("shed", *files_to_format, *doc_files_to_format)
-    # FIXME: work through the typing issues and enable py39 formatting
-    # pip_tool("shed", "--py39-plus", *files_to_format, *doc_files_to_format)
+    pip_tool("shed", "--py39-plus", *files_to_format, *doc_files_to_format)
 
 
 VALID_STARTS = (HEADER.split()[0], "#!/usr/bin/env python")