refactor: Move _getmro() to sphinx.util.inspect module

1 files changed, 16 insertions, 0 deletions

diff --git a/sphinx/util/inspect.py b/sphinx/util/inspect.py
index df469a5ae..a26c818c0 100644
--- a/sphinx/util/inspect.py
+++ b/sphinx/util/inspect.py
@@ -36,6 +36,10 @@ else:
     MethodDescriptorType = type(str.join)
     WrapperDescriptorType = type(dict.__dict__['fromkeys'])
 
+if False:
+    # For type annotation
+    from typing import Type  # NOQA
+
 logger = logging.getLogger(__name__)
 
 memory_address_re = re.compile(r' at 0x[0-9a-f]{8,16}(?=>)', re.IGNORECASE)
@@ -166,6 +170,18 @@ def getannotations(obj: Any) -> Mapping[str, Any]:
         return {}
 
 
+def getmro(obj: Any) -> Tuple["Type", ...]:
+    """Get __mro__ from given *obj* safely.
+
+    Raises AttributeError if given *obj* raises an error on accessing __mro__.
+    """
+    __mro__ = safe_getattr(obj, '__mro__', None)
+    if isinstance(__mro__, tuple):
+        return __mro__
+    else:
+        return tuple()
+
+
 def getslots(obj: Any) -> Optional[Dict]:
     """Get __slots__ attribute of the class as dict.