Fix #8541: autodoc_type_aliases doesn't work for the instance attrs

So far, autodoc obtains type annotations of instance attributes by
ModuleAnalyzer directly.  As a result, autodoc_type_aliases are ignored
for these variables.

This goes to merge type annotations from the class itself and
ModuleAnalyzer's, and get type annotations using `typing.get_type_hints()`
to apply autodoc_type_aliases.

5 files changed, 100 insertions, 18 deletions

diff --git a/CHANGES b/CHANGES
index b95582e2c..abb53c448 100644
--- a/CHANGES
+++ b/CHANGES
@@ -71,6 +71,8 @@ Bugs fixed
   attribute in alias class
 * #8452: autodoc: autodoc_type_aliases doesn't work when autodoc_typehints is
   set to "description"
+* #8541: autodoc: autodoc_type_aliases doesn't work for the type annotation to
+  instance attributes
 * #8460: autodoc: autodata and autoattribute directives do not display type
   information of TypeVars
 * #8493: autodoc: references to builtins not working in class aliases
diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index 267adb0bb..8f6136bf3 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -1843,6 +1843,26 @@ class DataDocumenter(GenericAliasMixin, NewTypeMixin, TypeVarMixin,
                             ) -> bool:
         return isinstance(parent, ModuleDocumenter) and isattr
 
+    def update_annotations(self, parent: Any) -> None:
+        """Update __annotations__ to support type_comment and so on."""
+        try:
+            annotations = inspect.getannotations(parent)
+
+            analyzer = ModuleAnalyzer.for_module(self.modname)
+            analyzer.analyze()
+            for (classname, attrname) in analyzer.annotations:
+                if classname == '' and attrname not in annotations:
+                    annotations[attrname] = analyzer.annotations[classname, attrname]  # type: ignore  # NOQA
+        except AttributeError:
+            pass
+
+    def import_object(self, raiseerror: bool = False) -> bool:
+        ret = super().import_object(raiseerror)
+        if self.parent:
+            self.update_annotations(self.parent)
+
+        return ret
+
     def add_directive_header(self, sig: str) -> None:
         super().add_directive_header(sig)
         sourcename = self.get_sourcename()
@@ -1857,11 +1877,6 @@ class DataDocumenter(GenericAliasMixin, NewTypeMixin, TypeVarMixin,
             if self.objpath[-1] in annotations:
                 objrepr = stringify_typehint(annotations.get(self.objpath[-1]))
                 self.add_line('   :type: ' + objrepr, sourcename)
-            else:
-                key = ('.'.join(self.objpath[:-1]), self.objpath[-1])
-                if self.analyzer and key in self.analyzer.annotations:
-                    self.add_line('   :type: ' + self.analyzer.annotations[key],
-                                  sourcename)
 
             try:
                 if self.options.no_value or self.should_suppress_value_header():
@@ -2259,6 +2274,26 @@ class AttributeDocumenter(GenericAliasMixin, NewTypeMixin, SlotsMixin,  # type:
 
         return False
 
+    def update_annotations(self, parent: Any) -> None:
+        """Update __annotations__ to support type_comment and so on."""
+        try:
+            annotations = inspect.getannotations(parent)
+
+            for cls in inspect.getmro(parent):
+                try:
+                    module = safe_getattr(cls, '__module__')
+                    qualname = safe_getattr(cls, '__qualname__')
+
+                    analyzer = ModuleAnalyzer.for_module(module)
+                    analyzer.analyze()
+                    for (classname, attrname) in analyzer.annotations:
+                        if classname == qualname and attrname not in annotations:
+                            annotations[attrname] = analyzer.annotations[classname, attrname]  # type: ignore  # NOQA
+                except (AttributeError, PycodeError):
+                    pass
+        except AttributeError:
+            pass
+
     def import_object(self, raiseerror: bool = False) -> bool:
         try:
             ret = super().import_object(raiseerror=True)
@@ -2275,6 +2310,9 @@ class AttributeDocumenter(GenericAliasMixin, NewTypeMixin, SlotsMixin,  # type:
                 self.env.note_reread()
                 ret = False
 
+        if self.parent:
+            self.update_annotations(self.parent)
+
         return ret
 
     def get_real_modname(self) -> str:
@@ -2294,16 +2332,6 @@ class AttributeDocumenter(GenericAliasMixin, NewTypeMixin, SlotsMixin,  # type:
             if self.objpath[-1] in annotations:
                 objrepr = stringify_typehint(annotations.get(self.objpath[-1]))
                 self.add_line('   :type: ' + objrepr, sourcename)
-            else:
-                try:
-                    qualname = safe_getattr(self.parent, '__qualname__',
-                                            '.'.join(self.objpath[:-1]))
-                    key = (qualname, self.objpath[-1])
-                    if self.analyzer and key in self.analyzer.annotations:
-                        self.add_line('   :type: ' + self.analyzer.annotations[key],
-                                      sourcename)
-                except AttributeError:
-                    pass
 
             try:
                 if (self.object is INSTANCEATTR or self.options.no_value or
diff --git a/tests/roots/test-ext-autodoc/target/annotations.py b/tests/roots/test-ext-autodoc/target/annotations.py
index e9ff2f604..ef600e2af 100644
--- a/tests/roots/test-ext-autodoc/target/annotations.py
+++ b/tests/roots/test-ext-autodoc/target/annotations.py
@@ -7,6 +7,9 @@ myint = int
 #: docstring
 variable: myint
 
+#: docstring
+variable2 = None  # type: myint
+
 
 def sum(x: myint, y: myint) -> myint:
     """docstring"""
@@ -32,4 +35,7 @@ class Foo:
     """docstring"""
 
     #: docstring
-    attr: myint
+    attr1: myint
+
+    def __init__(self):
+        self.attr2: myint = None  #: docstring
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index 52f69dd2e..a81a73b61 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -1675,9 +1675,25 @@ def test_autodoc_typed_inherited_instance_variables(app):
         '',
         '   .. py:attribute:: Derived.attr3',
         '      :module: target.typed_vars',
+        '      :type: int',
         '      :value: 0',
         '',
         '',
+        '   .. py:attribute:: Derived.attr4',
+        '      :module: target.typed_vars',
+        '      :type: int',
+        '',
+        '',
+        '   .. py:attribute:: Derived.attr5',
+        '      :module: target.typed_vars',
+        '      :type: int',
+        '',
+        '',
+        '   .. py:attribute:: Derived.attr6',
+        '      :module: target.typed_vars',
+        '      :type: int',
+        '',
+        '',
         '   .. py:attribute:: Derived.attr7',
         '      :module: target.typed_vars',
         '      :type: int',
diff --git a/tests/test_ext_autodoc_configs.py b/tests/test_ext_autodoc_configs.py
index d76ed25e3..ac0a2c11c 100644
--- a/tests/test_ext_autodoc_configs.py
+++ b/tests/test_ext_autodoc_configs.py
@@ -707,7 +707,14 @@ def test_autodoc_type_aliases(app):
         '   docstring',
         '',
         '',
-        '   .. py:attribute:: Foo.attr',
+        '   .. py:attribute:: Foo.attr1',
+        '      :module: target.annotations',
+        '      :type: int',
+        '',
+        '      docstring',
+        '',
+        '',
+        '   .. py:attribute:: Foo.attr2',
         '      :module: target.annotations',
         '      :type: int',
         '',
@@ -733,6 +740,14 @@ def test_autodoc_type_aliases(app):
         '',
         '   docstring',
         '',
+        '',
+        '.. py:data:: variable2',
+        '   :module: target.annotations',
+        '   :type: int',
+        '   :value: None',
+        '',
+        '   docstring',
+        '',
     ]
 
     # define aliases
@@ -749,7 +764,14 @@ def test_autodoc_type_aliases(app):
         '   docstring',
         '',
         '',
-        '   .. py:attribute:: Foo.attr',
+        '   .. py:attribute:: Foo.attr1',
+        '      :module: target.annotations',
+        '      :type: myint',
+        '',
+        '      docstring',
+        '',
+        '',
+        '   .. py:attribute:: Foo.attr2',
         '      :module: target.annotations',
         '      :type: myint',
         '',
@@ -775,6 +797,14 @@ def test_autodoc_type_aliases(app):
         '',
         '   docstring',
         '',
+        '',
+        '.. py:data:: variable2',
+        '   :module: target.annotations',
+        '   :type: myint',
+        '   :value: None',
+        '',
+        '   docstring',
+        '',
     ]