fix: Recursively evaluate guarded code (#393)

* Add test for nested guarded imports

* Handle nested type guards

* Refactor

---------

Co-authored-by: Bernát Gábor <[email protected]>

src/sphinx_autodoc_typehints/__init__.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 import ast
+import importlib
 import inspect
 import re
 import sys
@@ -404,32 +405,56 @@ def get_all_type_hints(autodoc_mock_imports: list[str], obj: Any, name: str) ->
 _TYPE_GUARD_IMPORTS_RESOLVED_GLOBALS_ID = set()
 
 
-def _resolve_type_guarded_imports(autodoc_mock_imports: list[str], obj: Any) -> None:  # noqa: C901
-    if hasattr(obj, "__module__") and obj.__module__ in _TYPE_GUARD_IMPORTS_RESOLVED:
-        return  # already processed module
-    if not hasattr(obj, "__globals__"):  # classes with __slots__ do not have this
-        return  # if lacks globals nothing we can do
-    if id(obj.__globals__) in _TYPE_GUARD_IMPORTS_RESOLVED_GLOBALS_ID:
-        return  # already processed object
-    _TYPE_GUARD_IMPORTS_RESOLVED.add(obj.__module__)
-    if obj.__module__ not in sys.builtin_module_names:
-        if hasattr(obj, "__globals__"):
-            _TYPE_GUARD_IMPORTS_RESOLVED_GLOBALS_ID.add(id(obj.__globals__))
-
-        module = inspect.getmodule(obj)
-        if module:
+def _should_skip_guarded_import_resolution(obj: Any) -> bool:
+    if isinstance(obj, types.ModuleType):
+        return False  # Don't skip modules
+
+    if not hasattr(obj, "__globals__"):
+        return True  # Skip objects without __globals__
+
+    if hasattr(obj, "__module__"):
+        return obj.__module__ in _TYPE_GUARD_IMPORTS_RESOLVED or obj.__module__ in sys.builtin_module_names
+
+    return id(obj.__globals__) in _TYPE_GUARD_IMPORTS_RESOLVED_GLOBALS_ID
+
+
+def _execute_guarded_code(autodoc_mock_imports: list[str], obj: Any, module_code: str) -> None:
+    for _, part in _TYPE_GUARD_IMPORT_RE.findall(module_code):
+        guarded_code = textwrap.dedent(part)
+        try:
             try:
-                module_code = inspect.getsource(module)
-            except (TypeError, OSError):
-                ...  # no source code => no type guards
-            else:
-                for _, part in _TYPE_GUARD_IMPORT_RE.findall(module_code):
-                    guarded_code = textwrap.dedent(part)
-                    try:
-                        with mock(autodoc_mock_imports):
-                            exec(guarded_code, obj.__globals__)  # noqa: S102
-                    except Exception as exc:  # noqa: BLE001
-                        _LOGGER.warning("Failed guarded type import with %r", exc)
+                with mock(autodoc_mock_imports):
+                    exec(guarded_code, getattr(obj, "__globals__", obj.__dict__))  # noqa: S102
+            except ImportError as exc:
+                # ImportError might have occurred because the module has guarded code as well,
+                # so we recurse on the module.
+                if exc.name:
+                    _resolve_type_guarded_imports(autodoc_mock_imports, importlib.import_module(exc.name))
+
+                    # Retry the guarded code and see if it works now after resolving all nested type guards.
+                    with mock(autodoc_mock_imports):
+                        exec(guarded_code, getattr(obj, "__globals__", obj.__dict__))  # noqa: S102
+        except Exception as exc:  # noqa: BLE001
+            _LOGGER.warning("Failed guarded type import with %r", exc)
+
+
+def _resolve_type_guarded_imports(autodoc_mock_imports: list[str], obj: Any) -> None:
+    if _should_skip_guarded_import_resolution(obj):
+        return
+
+    if hasattr(obj, "__globals__"):
+        _TYPE_GUARD_IMPORTS_RESOLVED_GLOBALS_ID.add(id(obj.__globals__))
+
+    module = inspect.getmodule(obj)
+
+    if module:
+        try:
+            module_code = inspect.getsource(module)
+        except (TypeError, OSError):
+            ...  # no source code => no type guards
+        else:
+            _TYPE_GUARD_IMPORTS_RESOLVED.add(module.__name__)
+            _execute_guarded_code(autodoc_mock_imports, obj, module_code)
 
 
 def _get_type_hint(autodoc_mock_imports: list[str], name: str, obj: Any) -> dict[str, Any]:

tests/roots/test-resolve-typing-guard/demo_typing_guard.py

@@ -12,6 +12,8 @@
     from decimal import Decimal
     from typing import Sequence
 
+    from demo_typing_guard_dummy import Literal  # guarded by another `if TYPE_CHECKING` in demo_typing_guard_dummy
+
 
 if typing.TYPE_CHECKING:
     from typing import AnyStr
@@ -52,6 +54,10 @@ def guarded(self, item: Decimal) -> None:
             """
 
 
+def func(_x: Literal) -> None:
+    ...
+
+
 __all__ = [
     "a",
     "ValueError",

tests/roots/test-resolve-typing-guard/demo_typing_guard_dummy.py

@@ -1,7 +1,13 @@
 from __future__ import annotations
 
+from typing import TYPE_CHECKING
+
 from viktor import AI  # module part of autodoc_mock_imports # noqa: F401
 
+if TYPE_CHECKING:
+    # Nested type guard
+    from typing import Literal  # noqa: F401
+
 
 class AnotherClass:
     """Another class is here"""