Support future and string annotations (#155)

Author: felix-hilden

docs/src/release_notes.rst

@@ -13,6 +13,7 @@ Unreleased
 - Declare support for Python 3.12 and 3.13 (:issue:`150`)
 - Remove support for Python 3.7 and 3.8 (:issue:`150`)
 - Fix changed whitespace handling in Pygments 2.19 (:issue:`152`)
+- Improve support for future and string annotations (:issue:`155`)
 
 0.15.2 (2024-06-03)
 -------------------

src/sphinx_codeautolink/extension/resolve.py

@@ -7,7 +7,8 @@
 from functools import cache
 from importlib import import_module
 from inspect import isclass, isroutine
-from typing import Any, Callable, Union
+from types import UnionType
+from typing import Any, Callable, Union, get_type_hints
 
 from sphinx_codeautolink.parse import Name, NameBreak
 
@@ -116,34 +117,27 @@ def call_value(cursor: Cursor) -> None:
 
 def get_return_annotation(func: Callable) -> type | None:
     """Determine the target of a function return type hint."""
-    annotations = getattr(func, "__annotations__", {})
-    ret_annotation = annotations.get("return", None)
+    annotation = get_type_hints(func).get("return")
 
     # Inner type from typing.Optional or Union[None, T]
-    origin = getattr(ret_annotation, "__origin__", None)
-    args = getattr(ret_annotation, "__args__", None)
-    if origin is Union and len(args) == 2:  # noqa: PLR2004
+    origin = getattr(annotation, "__origin__", None)
+    args = getattr(annotation, "__args__", None)
+    if (origin is Union or isinstance(annotation, UnionType)) and len(args) == 2:  # noqa: PLR2004
         nonetype = type(None)
         if args[0] is nonetype:
-            ret_annotation = args[1]
+            annotation = args[1]
         elif args[1] is nonetype:
-            ret_annotation = args[0]
-
-    # Try to resolve a string annotation in the module scope
-    if isinstance(ret_annotation, str):
-        location = fully_qualified_name(func)
-        mod, _ = closest_module(tuple(location.split(".")))
-        ret_annotation = getattr(mod, ret_annotation, ret_annotation)
+            annotation = args[0]
 
     if (
-        not ret_annotation
-        or not isinstance(ret_annotation, type)
-        or hasattr(ret_annotation, "__origin__")
+        not annotation
+        or not isinstance(annotation, type)
+        or hasattr(annotation, "__origin__")
     ):
         msg = f"Unable to follow return annotation of {get_name_for_debugging(func)}."
         raise CouldNotResolve(msg)
 
-    return ret_annotation
+    return annotation
 
 
 def fully_qualified_name(thing: type | Callable) -> str:

tests/extension/ref/ref_optional.txt

@@ -1,6 +1,8 @@
 test_project
 test_project.optional
 attr
+test_project.optional_manual
+attr
 # split
 # split
 Test project
@@ -10,5 +12,6 @@ Test project
 
    import test_project
    test_project.optional().attr
+   test_project.optional_manual().attr
 
 .. automodule:: test_project

tests/extension/ref/ref_optional_future.txt

@@ -0,0 +1,17 @@
+future_project
+future_project.optional
+attr
+future_project.optional_manual
+attr
+# split
+# split
+Test project
+============
+
+.. code:: python
+
+   import future_project
+   future_project.optional().attr
+   future_project.optional_manual().attr
+
+.. automodule:: future_project

tests/extension/ref/ref_optional_manual.txt

@@ -0,0 +1,18 @@
+# noqa: INP001
+from __future__ import annotations
+
+from typing import Optional
+
+
+class Foo:
+    """Foo test class."""
+
+    attr: str = "test"
+
+
+def optional() -> Optional[Foo]:  # noqa: UP007
+    """Return optional type."""
+
+
+def optional_manual() -> None | Foo:
+    """Return manually constructed optional type."""