Fix/pep 563 class init annotations parsing (#107)

* fix: handle class init

* refactor: improve readability

* test: cover annotations parsing in class init

* version: bump to new 0.76.0 version

* docs: refer to optional annotated cpython issue #90353

---------

Co-authored-by: Adrian Garcia Badaracco <1755071+adriangb@users.noreply.github.com>

Author: maxzhenzhera

di/_utils/inspect.py

@@ -47,17 +47,27 @@ def is_gen_callable(call: Any) -> bool:
 
 def get_annotations(call: Callable[..., Any]) -> Dict[str, Any]:
     types_from: Callable[..., Any]
-    if not (
-        inspect.isclass(call) or inspect.isfunction(call) or inspect.ismethod(call)
-    ) and hasattr(call, "__call__"):
-        # callable class
-        types_from = call.__call__  # type: ignore[misc,operator] # accessing __init__ directly
+    if inspect.isclass(call):
+        types_from = call.__init__
+    elif is_callable_class(call):
+        types_from = call.__call__  # type: ignore[operator] # mypy issue #5079
     else:
-        # method
         types_from = call
+
     hints = get_type_hints(types_from, include_extras=True)
-    # for no apparent reason, Annotated[Optional[T]] comes back as Optional[Annotated[Optional[T]]]
-    # so remove the outer Optional if this is the case
+    hints = fix_annotated_optional_type_hints(hints)
+
+    return hints
+
+
+def is_callable_class(call: Callable[..., Any]) -> bool:
+    function_or_method = inspect.isfunction(call) or inspect.ismethod(call)
+    has_call = hasattr(call, "__call__")
+    return not function_or_method and has_call
+
+
+def fix_annotated_optional_type_hints(hints: Dict[str, Any]) -> Dict[str, Any]:
+    """https://github.com/python/cpython/issues/90353"""
     for param_name, hint in hints.items():
         args = get_args(hint)
         if get_origin(hint) is Union and get_origin(next(iter(args))) is Annotated:

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "di"
-version = "0.75.4"
+version = "0.76.0"
 description = "Dependency injection toolkit"
 authors = ["Adrian Garcia Badaracco <adrian@adriangb.com>"]
 readme = "README.md"

tests/test_wiring_pep_563.py

@@ -10,11 +10,26 @@ def __call__(self: Test) -> Test:
         return self
 
 
-def test_postponed_evaluation_solving():
+def test_postponed_evaluation_solving_in_call():
     container = Container()
     with container.enter_scope(None) as state:
         res = container.solve(Dependent(Test.__call__), scopes=[None]).execute_sync(
             executor=SyncExecutor(),
             state=state,
         )
     assert isinstance(res, Test)
+
+
+class NeedsTest:
+    def __init__(self, test: Test) -> None:
+        self.test = test
+
+
+def test_postponed_evaluation_solving_in_init():
+    container = Container()
+    with container.enter_scope(None) as state:
+        res = container.solve(Dependent(NeedsTest), scopes=[None]).execute_sync(
+            executor=SyncExecutor(),
+            state=state,
+        )
+    assert isinstance(res, NeedsTest)