From 0dbbf1dd540fedc470add85db0eea934c2373db6 Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Thu, 17 Dec 2020 01:04:03 +0900
Subject: [PATCH] Fix #8534: autoattribute failed to document a commented
 attribute in alias dervied class

---
 sphinx/ext/autodoc/__init__.py                | 19 ++++++++++++-------
 .../test-ext-autodoc/target/typed_vars.py     |  2 +-
 tests/test_ext_autodoc.py                     |  8 +++++++-
 3 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index 9ae115ef4..2bec46859 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -2152,14 +2152,19 @@ class UninitializedInstanceAttributeMixin(DataDocumenterMixinBase):
 
     def get_attribute_comment(self, parent: Any) -> Optional[List[str]]:
         try:
-            analyzer = ModuleAnalyzer.for_module(self.modname)
-            analyzer.analyze()
+            for cls in inspect.getmro(parent):
+                try:
+                    module = safe_getattr(cls, '__module__')
+                    qualname = safe_getattr(cls, '__qualname__')
 
-            qualname = safe_getattr(parent, '__qualname__', None)
-            if qualname and self.objpath:
-                key = (qualname, self.objpath[-1])
-                if key in analyzer.attr_docs:
-                    return list(analyzer.attr_docs[key])
+                    analyzer = ModuleAnalyzer.for_module(module)
+                    analyzer.analyze()
+                    if qualname and self.objpath:
+                        key = (qualname, self.objpath[-1])
+                        if key in analyzer.attr_docs:
+                            return list(analyzer.attr_docs[key])
+                except (AttributeError, PycodeError):
+                    pass
         except (AttributeError, PycodeError):
             pass
 
diff --git a/tests/roots/test-ext-autodoc/target/typed_vars.py b/tests/roots/test-ext-autodoc/target/typed_vars.py
index 4e2de2398..f909b80f1 100644
--- a/tests/roots/test-ext-autodoc/target/typed_vars.py
+++ b/tests/roots/test-ext-autodoc/target/typed_vars.py
@@ -31,4 +31,4 @@ class Derived(Class):
     attr7: int
 
 
-Alias = Class
+Alias = Derived
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index a81a73b61..8d2738f1b 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -1564,7 +1564,7 @@ def test_autodoc_typed_instance_variables(app):
         '.. py:attribute:: Alias',
         '   :module: target.typed_vars',
         '',
-        '   alias of :class:`target.typed_vars.Class`',
+        '   alias of :class:`target.typed_vars.Derived`',
         '',
         '.. py:class:: Class()',
         '   :module: target.typed_vars',
@@ -1683,16 +1683,22 @@ def test_autodoc_typed_inherited_instance_variables(app):
         '      :module: target.typed_vars',
         '      :type: int',
         '',
+        '      attr4',
+        '',
         '',
         '   .. py:attribute:: Derived.attr5',
         '      :module: target.typed_vars',
         '      :type: int',
         '',
+        '      attr5',
+        '',
         '',
         '   .. py:attribute:: Derived.attr6',
         '      :module: target.typed_vars',
         '      :type: int',
         '',
+        '      attr6',
+        '',
         '',
         '   .. py:attribute:: Derived.attr7',
         '      :module: target.typed_vars',