Fix #7383: autodoc: Support typehints for properties

py:property directive now outputs py:property directive to describe
its type annotation.

CHANGES

@@ -62,6 +62,7 @@ Features added
 --------------
 
 * #8924: autodoc: Support ``bound`` argument for TypeVar
+* #7383: autodoc: Support typehints for properties
 * #7549: autosummary: Enable :confval:`autosummary_generate` by default
 * #4826: py domain: Add ``:canonical:`` option to python directives to describe
   the location where the object is defined

sphinx/ext/autodoc/__init__.py

@@ -2526,7 +2526,6 @@ class PropertyDocumenter(DocstringStripSignatureMixin, ClassLevelDocumenter):  #
     Specialized Documenter subclass for properties.
     """
     objtype = 'property'
-    directivetype = 'method'
     member_order = 60
 
     # before AttributeDocumenter
@@ -2549,7 +2548,20 @@ class PropertyDocumenter(DocstringStripSignatureMixin, ClassLevelDocumenter):  #
         sourcename = self.get_sourcename()
         if inspect.isabstractmethod(self.object):
             self.add_line('   :abstractmethod:', sourcename)
-        self.add_line('   :property:', sourcename)
+
+        if safe_getattr(self.object, 'fget', None):
+            try:
+                signature = inspect.signature(self.object.fget,
+                                              type_aliases=self.config.autodoc_type_aliases)
+                if signature.return_annotation is not Parameter.empty:
+                    objrepr = stringify_typehint(signature.return_annotation)
+                    self.add_line('   :type: ' + objrepr, sourcename)
+            except TypeError as exc:
+                logger.warning(__("Failed to get a function signature for %s: %s"),
+                               self.fullname, exc)
+                return None
+            except ValueError:
+                raise
 
 
 class NewTypeAttributeDocumenter(AttributeDocumenter):

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

@@ -0,0 +1,6 @@
+class Foo:
+    """docstring"""
+
+    @property
+    def prop(self) -> int:
+        """docstring"""

tests/test_ext_autodoc.py

@@ -1033,9 +1033,8 @@ def test_autodoc_descriptor(app):
         '      Descriptor instance docstring.',
         '',
         '',
-        '   .. py:method:: Class.prop',
+        '   .. py:property:: Class.prop',
         '      :module: target.descriptor',
-        '      :property:',
         '',
         '      Property.',
         ''
@@ -1055,9 +1054,8 @@ def test_autodoc_cached_property(app):
         '   :module: target.cached_property',
         '',
         '',
-        '   .. py:method:: Foo.prop',
+        '   .. py:property:: Foo.prop',
         '      :module: target.cached_property',
-        '      :property:',
         '',
     ]
 
@@ -1516,10 +1514,9 @@ def test_abstractmethods(app):
         '      :module: target.abstractmethods',
         '',
         '',
-        '   .. py:method:: Base.prop',
+        '   .. py:property:: Base.prop',
         '      :module: target.abstractmethods',
         '      :abstractmethod:',
-        '      :property:',
         '',
         '',
         '   .. py:method:: Base.staticmeth()',

tests/test_ext_autodoc_autoclass.py

@@ -199,6 +199,27 @@ def test_decorators(app):
     ]
 
 
+@pytest.mark.sphinx('html', testroot='ext-autodoc')
+def test_properties(app):
+    options = {"members": None}
+    actual = do_autodoc(app, 'class', 'target.properties.Foo', options)
+    assert list(actual) == [
+        '',
+        '.. py:class:: Foo()',
+        '   :module: target.properties',
+        '',
+        '   docstring',
+        '',
+        '',
+        '   .. py:property:: Foo.prop',
+        '      :module: target.properties',
+        '      :type: int',
+        '',
+        '      docstring',
+        '',
+    ]
+
+
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_slots_attribute(app):
     options = {"members": None}

tests/test_ext_autodoc_autoproperty.py

@@ -0,0 +1,28 @@
+"""
+    test_ext_autodoc_autoproperty
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Test the autodoc extension.  This tests mainly the Documenters; the auto
+    directives are tested in a test source file translated by test_build.
+
+    :copyright: Copyright 2007-2021 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+import pytest
+
+from .test_ext_autodoc import do_autodoc
+
+
+@pytest.mark.sphinx('html', testroot='ext-autodoc')
+def test_properties(app):
+    actual = do_autodoc(app, 'property', 'target.properties.Foo.prop')
+    assert list(actual) == [
+        '',
+        '.. py:property:: Foo.prop',
+        '   :module: target.properties',
+        '   :type: int',
+        '',
+        '   docstring',
+        '',
+    ]

tests/test_ext_autodoc_configs.py

@@ -261,16 +261,14 @@ def test_autodoc_docstring_signature(app):
         '          indented line',
         '',
         '',
-        '   .. py:method:: DocstringSig.prop1',
+        '   .. py:property:: DocstringSig.prop1',
         '      :module: target',
-        '      :property:',
         '',
         '      First line of docstring',
         '',
         '',
-        '   .. py:method:: DocstringSig.prop2',
+        '   .. py:property:: DocstringSig.prop2',
         '      :module: target',
-        '      :property:',
         '',
         '      First line of docstring',
         '      Second line of docstring',
@@ -305,17 +303,15 @@ def test_autodoc_docstring_signature(app):
         '          indented line',
         '',
         '',
-        '   .. py:method:: DocstringSig.prop1',
+        '   .. py:property:: DocstringSig.prop1',
         '      :module: target',
-        '      :property:',
         '',
         '      DocstringSig.prop1(self)',
         '      First line of docstring',
         '',
         '',
-        '   .. py:method:: DocstringSig.prop2',
+        '   .. py:property:: DocstringSig.prop2',
         '      :module: target',
-        '      :property:',
         '',
         '      First line of docstring',
         '      Second line of docstring',