Fix KeyError with type hints on the first arg of bound methods (#200)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Bernát Gábor <[email protected]>

CHANGELOG.md

@@ -3,6 +3,8 @@
 ## dev
 
 - Fixed `normalize_source_lines()` messing with the indentation of methods with decorators that have parameters starting with `def`.
+- Handle `ValueError` or `TypeError` being raised when signature of an object cannot be determined
+- Fix `KeyError` being thrown when argument is not documented (e.g. `cls` argument for class methods, and `self` for methods)
 
 ## 1.14.0
 

src/sphinx_autodoc_typehints/__init__.py

@@ -454,7 +454,10 @@ def process_docstring(
     for arg_name, annotation in type_hints.items():
         if arg_name == "return":
             continue  # this is handled separately later
-        default = inspect.Parameter.empty if signature is None else signature.parameters[arg_name].default
+        if signature is None or arg_name not in signature.parameters:
+            default = inspect.Parameter.empty
+        else:
+            default = signature.parameters[arg_name].default
         if arg_name.endswith("_"):
             arg_name = f"{arg_name[:-1]}\\_"
 

tests/test_sphinx_autodoc_typehints.py

@@ -7,7 +7,7 @@
 from functools import cmp_to_key
 from io import StringIO
 from textwrap import dedent, indent
-from types import ModuleType
+from types import FunctionType, ModuleType
 from typing import (
     IO,
     Any,
@@ -54,7 +54,7 @@ def get_type(self) -> type:
         return type(self)
 
     class Inner:
-        pass
+        ...
 
 
 class B(Generic[T]):
@@ -63,23 +63,32 @@ class B(Generic[T]):
 
 
 class C(B[str]):
-    pass
+    ...
 
 
 class D(typing_extensions.Protocol):
-    pass
+    ...
 
 
 class E(typing_extensions.Protocol[T]):  # type: ignore #  Invariant type variable "T" used in protocol where covariant
-    pass
+    ...
 
 
 class Slotted:
     __slots__ = ()
 
 
 class Metaclass(type):
-    pass
+    ...
+
+
+class HintedMethods:
+    @classmethod
+    def from_magic(cls: type[T]) -> T:
+        ...
+
+    def method(self: T) -> T:
+        ...
 
 
 PY310_PLUS = sys.version_info >= (3, 10)
@@ -673,13 +682,13 @@ def test_normalize_source_lines_async_def() -> None:
     source = """
     async def async_function():
         class InnerClass:
-            def __init__(self): pass
+            def __init__(self): ...
     """
 
     expected = """
     async def async_function():
         class InnerClass:
-            def __init__(self): pass
+            def __init__(self): ...
     """
 
     assert normalize_source_lines(dedent(source)) == dedent(expected)
@@ -699,7 +708,7 @@ def test_normalize_source_lines_def_starting_decorator_parameter() -> None:
         ),
     )
     def __init__(bound_args):  # noqa: N805
-        pass
+        ...
     """
 
     expected = """
@@ -715,7 +724,7 @@ def __init__(bound_args):  # noqa: N805
         ),
     )
     def __init__(bound_args):  # noqa: N805
-        pass
+        ...
     """
 
     assert normalize_source_lines(dedent(source)) == dedent(expected)
@@ -728,3 +737,17 @@ def test_default_no_signature(obj: Any) -> None:
     lines: list[str] = []
     process_docstring(app, "what", "name", obj, None, lines)
     assert lines == []
+
+
+@pytest.mark.parametrize("method", [HintedMethods.from_magic, HintedMethods().method])
+def test_bound_class_method(method: FunctionType) -> None:
+    config = create_autospec(
+        Config,
+        typehints_fully_qualified=False,
+        simplify_optional_unions=False,
+        typehints_document_rtype=False,
+        always_document_param_types=True,
+        typehints_defaults=True,
+    )
+    app: Sphinx = create_autospec(Sphinx, config=config)
+    process_docstring(app, "class", method.__qualname__, method, None, [])