Fix #8503: autoattribute could not create document for a GenericAlias

9 files changed, 128 insertions, 34 deletions

diff --git a/CHANGES b/CHANGES
index 1ea53bfc5..769b29ab0 100644
--- a/CHANGES
+++ b/CHANGES
@@ -16,6 +16,7 @@ Deprecated
 * The ``follow_wrapped`` argument of ``sphinx.util.inspect.signature()``
 * ``sphinx.ext.autodoc.Documenter.get_object_members()``
 * ``sphinx.ext.autodoc.DataDeclarationDocumenter``
+* ``sphinx.ext.autodoc.GenericAliasDocumenter``
 * ``sphinx.ext.autodoc.InstanceAttributeDocumenter``
 * ``sphinx.ext.autodoc.SlotsAttributeDocumenter``
 * ``sphinx.ext.autodoc.TypeVarDocumenter``
@@ -60,6 +61,8 @@ Bugs fixed
   based uninitalized variables
 * #8480: autodoc: autoattribute could not create document for __slots__
   attributes
+* #8503: autodoc: autoattribute could not create document for a GenericAlias as
+  class attributes correctly
 * #8452: autodoc: autodoc_type_aliases doesn't work when autodoc_typehints is
   set to "description"
 * #8460: autodoc: autodata and autoattribute directives do not display type
diff --git a/doc/extdev/deprecated.rst b/doc/extdev/deprecated.rst
index bbd9d283e..068bf899b 100644
--- a/doc/extdev/deprecated.rst
+++ b/doc/extdev/deprecated.rst
@@ -41,6 +41,11 @@ The following is a list of deprecated interfaces.
      - 5.0
      - ``sphinx.ext.autodoc.DataDocumenter``
 
+   * - ``sphinx.ext.autodoc.GenericAliasDocumenter``
+     - 3.4
+     - 5.0
+     - ``sphinx.ext.autodoc.DataDocumenter``
+
    * - ``sphinx.ext.autodoc.InstanceAttributeDocumenter``
      - 3.4
      - 5.0
diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index f77852c13..ea2818800 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -1701,6 +1701,25 @@ class DataDocumenterMixinBase:
         pass
 
 
+class GenericAliasMixin(DataDocumenterMixinBase):
+    """
+    Mixin for DataDocumenter and AttributeDocumenter to provide the feature for
+    supporting GenericAliases.
+    """
+
+    def should_suppress_directive_header(self) -> bool:
+        return (inspect.isgenericalias(self.object) or
+                super().should_suppress_directive_header())
+
+    def update_content(self, more_content: StringList) -> None:
+        if inspect.isgenericalias(self.object):
+            alias = stringify_typehint(self.object)
+            more_content.append(_('alias of %s') % alias, '')
+            more_content.append('', '')
+
+        super().update_content(more_content)
+
+
 class NewTypeMixin(DataDocumenterMixinBase):
     """
     Mixin for DataDocumenter and AttributeDocumenter to provide the feature for
@@ -1801,8 +1820,8 @@ class UninitializedGlobalVariableMixin(DataDocumenterMixinBase):
             super().add_content(more_content, no_docstring=no_docstring)  # type: ignore
 
 
-class DataDocumenter(NewTypeMixin, TypeVarMixin, UninitializedGlobalVariableMixin,
-                     ModuleLevelDocumenter):
+class DataDocumenter(GenericAliasMixin, NewTypeMixin, TypeVarMixin,
+                     UninitializedGlobalVariableMixin, ModuleLevelDocumenter):
     """
     Specialized Documenter subclass for data items.
     """
@@ -1863,32 +1882,6 @@ class DataDocumenter(NewTypeMixin, TypeVarMixin, UninitializedGlobalVariableMixi
         super().add_content(more_content, no_docstring=no_docstring)
 
 
-class GenericAliasDocumenter(DataDocumenter):
-    """
-    Specialized Documenter subclass for GenericAliases.
-    """
-
-    objtype = 'genericalias'
-    directivetype = 'data'
-    priority = DataDocumenter.priority + 1
-
-    @classmethod
-    def can_document_member(cls, member: Any, membername: str, isattr: bool, parent: Any
-                            ) -> bool:
-        return inspect.isgenericalias(member)
-
-    def add_directive_header(self, sig: str) -> None:
-        self.options = Options(self.options)
-        self.options['annotation'] = SUPPRESS
-        super().add_directive_header(sig)
-
-    def add_content(self, more_content: Optional[StringList], no_docstring: bool = False
-                    ) -> None:
-        name = stringify_typehint(self.object)
-        content = StringList([_('alias of %s') % name], source='')
-        super().add_content(content)
-
-
 class NewTypeDataDocumenter(DataDocumenter):
     """
     Specialized Documenter subclass for NewTypes.
@@ -2102,8 +2095,8 @@ class SlotsMixin(DataDocumenterMixinBase):
             return super().get_doc(encoding, ignore)  # type: ignore
 
 
-class AttributeDocumenter(NewTypeMixin, SlotsMixin, TypeVarMixin,  # type: ignore
-                          DocstringStripSignatureMixin, ClassLevelDocumenter):
+class AttributeDocumenter(GenericAliasMixin, NewTypeMixin, SlotsMixin,  # type: ignore
+                          TypeVarMixin, DocstringStripSignatureMixin, ClassLevelDocumenter):
     """
     Specialized Documenter subclass for attributes.
     """
@@ -2324,6 +2317,7 @@ def migrate_autodoc_member_order(app: Sphinx, config: Config) -> None:
 
 # for compatibility
 from sphinx.ext.autodoc.deprecated import DataDeclarationDocumenter  # NOQA
+from sphinx.ext.autodoc.deprecated import GenericAliasDocumenter  # NOQA
 from sphinx.ext.autodoc.deprecated import InstanceAttributeDocumenter  # NOQA
 from sphinx.ext.autodoc.deprecated import SingledispatchFunctionDocumenter  # NOQA
 from sphinx.ext.autodoc.deprecated import SingledispatchMethodDocumenter  # NOQA
@@ -2336,7 +2330,6 @@ def setup(app: Sphinx) -> Dict[str, Any]:
     app.add_autodocumenter(ClassDocumenter)
     app.add_autodocumenter(ExceptionDocumenter)
     app.add_autodocumenter(DataDocumenter)
-    app.add_autodocumenter(GenericAliasDocumenter)
     app.add_autodocumenter(NewTypeDataDocumenter)
     app.add_autodocumenter(FunctionDocumenter)
     app.add_autodocumenter(DecoratorDocumenter)
diff --git a/sphinx/ext/autodoc/deprecated.py b/sphinx/ext/autodoc/deprecated.py
index c6ca13105..5541a7a91 100644
--- a/sphinx/ext/autodoc/deprecated.py
+++ b/sphinx/ext/autodoc/deprecated.py
@@ -109,3 +109,18 @@ class SlotsAttributeDocumenter(AttributeDocumenter):
         warnings.warn("%s is deprecated." % self.__class__.__name__,
                       RemovedInSphinx50Warning, stacklevel=2)
         super().__init__(*args, **kwargs)
+
+
+class GenericAliasDocumenter(DataDocumenter):
+    """
+    Specialized Documenter subclass for GenericAliases.
+    """
+
+    objtype = 'genericalias'
+    directivetype = 'data'
+    priority = DataDocumenter.priority + 1  # type: ignore
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        warnings.warn("%s is deprecated." % self.__class__.__name__,
+                      RemovedInSphinx50Warning, stacklevel=2)
+        super().__init__(*args, **kwargs)
diff --git a/sphinx/ext/autosummary/generate.py b/sphinx/ext/autosummary/generate.py
index 2dc936591..10f8ca913 100644
--- a/sphinx/ext/autosummary/generate.py
+++ b/sphinx/ext/autosummary/generate.py
@@ -87,15 +87,14 @@ AutosummaryEntry = NamedTuple('AutosummaryEntry', [('name', str),
 def setup_documenters(app: Any) -> None:
     from sphinx.ext.autodoc import (AttributeDocumenter, ClassDocumenter, DataDocumenter,
                                     DecoratorDocumenter, ExceptionDocumenter,
-                                    FunctionDocumenter, GenericAliasDocumenter,
-                                    MethodDocumenter, ModuleDocumenter,
+                                    FunctionDocumenter, MethodDocumenter, ModuleDocumenter,
                                     NewTypeAttributeDocumenter, NewTypeDataDocumenter,
                                     PropertyDocumenter, SingledispatchFunctionDocumenter)
     documenters = [
         ModuleDocumenter, ClassDocumenter, ExceptionDocumenter, DataDocumenter,
         FunctionDocumenter, MethodDocumenter, NewTypeAttributeDocumenter,
         NewTypeDataDocumenter, AttributeDocumenter, DecoratorDocumenter, PropertyDocumenter,
-        GenericAliasDocumenter, SingledispatchFunctionDocumenter,
+        SingledispatchFunctionDocumenter,
     ]  # type: List[Type[Documenter]]
     for documenter in documenters:
         app.registry.add_documenter(documenter.objtype, documenter)
diff --git a/tests/roots/test-ext-autodoc/target/genericalias.py b/tests/roots/test-ext-autodoc/target/genericalias.py
index d37bcb7fa..9909efca1 100644
--- a/tests/roots/test-ext-autodoc/target/genericalias.py
+++ b/tests/roots/test-ext-autodoc/target/genericalias.py
@@ -4,3 +4,8 @@ from typing import Callable, List
 T = List[int]
 
 C = Callable[[int], None]  # a generic alias not having a doccomment
+
+
+class Class:
+    #: A list of int
+    T = List[int]
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index 000ddc0c5..02ffae549 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -1701,6 +1701,15 @@ def test_autodoc_GenericAlias(app):
             '.. py:module:: target.genericalias',
             '',
             '',
+            '.. py:class:: Class()',
+            '   :module: target.genericalias',
+            '',
+            '',
+            '   .. py:attribute:: Class.T',
+            '      :module: target.genericalias',
+            '',
+            '      alias of :class:`List`\\ [:class:`int`]',
+            '',
             '.. py:attribute:: T',
             '   :module: target.genericalias',
             '',
@@ -1712,12 +1721,25 @@ def test_autodoc_GenericAlias(app):
             '.. py:module:: target.genericalias',
             '',
             '',
+            '.. py:class:: Class()',
+            '   :module: target.genericalias',
+            '',
+            '',
+            '   .. py:attribute:: Class.T',
+            '      :module: target.genericalias',
+            '',
+            '      A list of int',
+            '',
+            '      alias of List[int]',
+            '',
+            '',
             '.. py:data:: T',
             '   :module: target.genericalias',
             '',
             '   A list of int',
             '',
             '   alias of List[int]',
+            '',
         ]
 
 
diff --git a/tests/test_ext_autodoc_autoattribute.py b/tests/test_ext_autodoc_autoattribute.py
index a0d5e5b6f..e44395ee3 100644
--- a/tests/test_ext_autodoc_autoattribute.py
+++ b/tests/test_ext_autodoc_autoattribute.py
@@ -108,6 +108,32 @@ def test_autoattribute_slots_variable_str(app):
 
 
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
+def test_autoattribute_GenericAlias(app):
+    actual = do_autodoc(app, 'attribute', 'target.genericalias.Class.T')
+    if sys.version_info < (3, 7):
+        assert list(actual) == [
+            '',
+            '.. py:attribute:: Class.T',
+            '   :module: target.genericalias',
+            '   :value: typing.List[int]',
+            '',
+            '   A list of int',
+            '',
+        ]
+    else:
+        assert list(actual) == [
+            '',
+            '.. py:attribute:: Class.T',
+            '   :module: target.genericalias',
+            '',
+            '   A list of int',
+            '',
+            '   alias of List[int]',
+            '',
+        ]
+
+
+@pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_autoattribute_NewType(app):
     actual = do_autodoc(app, 'attribute', 'target.typevar.Class.T6')
     assert list(actual) == [
diff --git a/tests/test_ext_autodoc_autodata.py b/tests/test_ext_autodoc_autodata.py
index dbf6103cb..d3f63f432 100644
--- a/tests/test_ext_autodoc_autodata.py
+++ b/tests/test_ext_autodoc_autodata.py
@@ -76,6 +76,32 @@ def test_autodata_type_comment(app):
 
 
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
+def test_autodata_GenericAlias(app):
+    actual = do_autodoc(app, 'data', 'target.genericalias.T')
+    if sys.version_info < (3, 7):
+        assert list(actual) == [
+            '',
+            '.. py:data:: T',
+            '   :module: target.genericalias',
+            '   :value: typing.List[int]',
+            '',
+            '   A list of int',
+            '',
+        ]
+    else:
+        assert list(actual) == [
+            '',
+            '.. py:data:: T',
+            '   :module: target.genericalias',
+            '',
+            '   A list of int',
+            '',
+            '   alias of List[int]',
+            '',
+        ]
+
+
+@pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_autodata_NewType(app):
     actual = do_autodoc(app, 'data', 'target.typevar.T6')
     assert list(actual) == [