Closes #10310: Sphinx automodule: class method not documented when de…

…corated with mocked function.

sphinx/ext/autodoc/mock.py

@@ -5,7 +5,7 @@
 import sys
 from importlib.abc import Loader, MetaPathFinder
 from importlib.machinery import ModuleSpec
-from types import ModuleType
+from types import MethodType, ModuleType
 from typing import Any, Generator, Iterator, List, Optional, Sequence, Tuple, Union
 
 from sphinx.util import logging
@@ -129,6 +129,13 @@ def invalidate_caches(self) -> None:
             sys.modules.pop(modname, None)
 
 
+def _method_is_bound(method):
+    try:
+        return method.__self__ is not None
+    except AttributeError:
+        return False
+
+
 @contextlib.contextmanager
 def mock(modnames: List[str]) -> Generator[None, None, None]:
     """Insert mock modules during context::
@@ -164,9 +171,15 @@ def ismock(subject: Any) -> bool:
     if isinstance(subject, _MockModule):
         return True
 
+    # check the object is bound method
+    if isinstance(subject, MethodType) and _method_is_bound(subject):
+        tmp_subject = subject.__func__
+    else:
+        tmp_subject = subject
+
     try:
         # check the object is mocked object
-        __mro__ = safe_getattr(type(subject), '__mro__', [])
+        __mro__ = safe_getattr(type(tmp_subject), '__mro__', [])
         if len(__mro__) > 2 and __mro__[-2] is _MockObject:
             # A mocked object has a MRO that ends with (..., _MockObject, object).
             return True
@@ -175,7 +188,6 @@ def ismock(subject: Any) -> bool:
 
     return False
 
-
 def undecorate(subject: _MockObject) -> Any:
     """Unwrap mock if *subject* is decorated by mocked object.