Fix #9866: autodoc: doccoment for the imported class was ignored

CHANGES

@@ -19,6 +19,7 @@ Features added
 Bugs fixed
 ----------
 
+* #9866: autodoc: doccoment for the imported class was ignored
 * #9857: Generated RFC links use outdated base url
 
 Testing

sphinx/ext/autodoc/__init__.py

@@ -1743,14 +1743,22 @@ def get_doc(self, ignore: int = None) -> Optional[List[List[str]]]:
     def get_variable_comment(self) -> Optional[List[str]]:
         try:
             key = ('', '.'.join(self.objpath))
-            analyzer = ModuleAnalyzer.for_module(self.get_real_modname())
+            if self.doc_as_attr:
+                analyzer = ModuleAnalyzer.for_module(self.modname)
+            else:
+                analyzer = ModuleAnalyzer.for_module(self.get_real_modname())
             analyzer.analyze()
-            return list(self.analyzer.attr_docs.get(key, []))
+            return list(analyzer.attr_docs.get(key, []))
         except PycodeError:
             return None
 
     def add_content(self, more_content: Optional[StringList], no_docstring: bool = False
                     ) -> None:
+        if self.doc_as_attr and self.modname != self.get_real_modname():
+            # override analyzer to obtain doccomment around its definition.
+            self.analyzer = ModuleAnalyzer.for_module(self.modname)
+            self.analyzer.analyze()
+
         if self.doc_as_attr and not self.get_variable_comment():
             try:
                 more_content = StringList([_('alias of %s') % restify(self.object)], source='')

tests/roots/test-ext-autodoc/target/classes.py

@@ -37,3 +37,6 @@ class Corge(Quux):
 
 #: docstring
 OtherAlias = Bar
+
+#: docstring
+IntAlias = int

tests/test_ext_autodoc.py

@@ -1870,12 +1870,15 @@ def test_autodoc_GenericAlias(app):
             '   .. py:attribute:: Class.T',
             '      :module: target.genericalias',
             '',
+            '      A list of int',
+            '',
             '      alias of :py:class:`~typing.List`\\ [:py:class:`int`]',
             '',
             '.. py:attribute:: T',
             '   :module: target.genericalias',
             '',
-            '   alias of :py:class:`~typing.List`\\ [:py:class:`int`]',
+            '   A list of int',
+            '',
         ]
     else:
         assert list(actual) == [

tests/test_ext_autodoc_autoclass.py

@@ -407,6 +407,18 @@ def test_class_alias_having_doccomment(app):
     ]
 
 
+def test_class_alias_for_imported_object_having_doccomment(app):
+    actual = do_autodoc(app, 'class', 'target.classes.IntAlias')
+    assert list(actual) == [
+        '',
+        '.. py:attribute:: IntAlias',
+        '   :module: target.classes',
+        '',
+        '   docstring',
+        '',
+    ]
+
+
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_coroutine(app):
     options = {"members": None}