Fix #8315: autodoc: Failed to resolve struct.Struct type annotation

The builtin module, ``struct.Struct`` does not have correct module
name since Python 3.8.  This allows to refer it automatically.

1 files changed, 7 insertions, 0 deletions

diff --git a/sphinx/util/typing.py b/sphinx/util/typing.py
index 2d4f67bba..f9807ae09 100644
--- a/sphinx/util/typing.py
+++ b/sphinx/util/typing.py
@@ -10,6 +10,7 @@
 
 import sys
 import typing
+from struct import Struct
 from typing import Any, Callable, Dict, Generator, List, Optional, Tuple, TypeVar, Union
 
 from docutils import nodes
@@ -94,6 +95,9 @@ def restify(cls: Optional["Type"]) -> str:
         return ':obj:`None`'
     elif cls is Ellipsis:
         return '...'
+    elif cls is Struct:
+        # Before Python 3.9, struct.Struct class has incorrect __module__.
+        return ':class:`struct.Struct`'
     elif inspect.isNewType(cls):
         return ':class:`%s`' % cls.__name__
     elif cls.__module__ in ('__builtin__', 'builtins'):
@@ -305,6 +309,9 @@ def stringify(annotation: Any) -> str:
         return annotation.__qualname__
     elif annotation is Ellipsis:
         return '...'
+    elif annotation is Struct:
+        # Before Python 3.9, struct.Struct class has incorrect __module__.
+        return 'struct.Struct'
 
     if sys.version_info >= (3, 7):  # py37+
         return _stringify_py37(annotation)