Fix #7613: autodoc: autodoc does not respect __signature__ of the class

CHANGES

@@ -52,6 +52,7 @@ Bugs fixed
 * #7786: autodoc: can't detect overloaded methods defined in other file
 * #8294: autodoc: single-string __slots__ is not handled correctly
 * #7785: autodoc: autodoc_typehints='none' does not effect to overloaded functions
+* #7613: autodoc: autodoc does not respect __signature__ of the class
 * #8192: napoleon: description is disappeared when it contains inline literals
 * #8142: napoleon: Potential of regex denial of service in google style docs
 * #8169: LaTeX: pxjahyper loaded even when latex_engine is not platex

sphinx/ext/autodoc/__init__.py

@@ -1391,7 +1391,12 @@ class ClassDocumenter(DocstringSignatureMixin, ModuleLevelDocumenter):  # type:
         # This sequence is copied from inspect._signature_from_callable.
         # ValueError means that no signature could be found, so we keep going.
 
-        # First, let's see if it has an overloaded __call__ defined
+        # First, we check the obj has a __signature__ attribute
+        if (hasattr(self.object, '__signature__') and
+                isinstance(self.object.__signature__, Signature)):
+            return None, None, self.object.__signature__
+
+        # Next, let's see if it has an overloaded __call__ defined
         # in its metaclass
         call = get_user_defined_function_or_method(type(self.object), '__call__')
 

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

@@ -1,3 +1,6 @@
+from inspect import Parameter, Signature
+
+
 class Foo:
     pass
 
@@ -10,3 +13,11 @@ class Bar:
 class Baz:
     def __new__(cls, x, y):
         pass
+
+
+class Qux:
+    __signature__ = Signature(parameters=[Parameter('foo', Parameter.POSITIONAL_OR_KEYWORD),
+                                          Parameter('bar', Parameter.POSITIONAL_OR_KEYWORD)])
+
+    def __init__(self, x, y):
+        pass

tests/test_ext_autodoc_autoclass.py

@@ -0,0 +1,50 @@
+"""
+    test_ext_autodoc_autoclass
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    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 2007-2020 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_classes(app):
+    actual = do_autodoc(app, 'function', 'target.classes.Foo')
+    assert list(actual) == [
+        '',
+        '.. py:function:: Foo()',
+        '   :module: target.classes',
+        '',
+    ]
+
+    actual = do_autodoc(app, 'function', 'target.classes.Bar')
+    assert list(actual) == [
+        '',
+        '.. py:function:: Bar(x, y)',
+        '   :module: target.classes',
+        '',
+    ]
+
+    actual = do_autodoc(app, 'function', 'target.classes.Baz')
+    assert list(actual) == [
+        '',
+        '.. py:function:: Baz(x, y)',
+        '   :module: target.classes',
+        '',
+    ]
+
+    actual = do_autodoc(app, 'function', 'target.classes.Qux')
+    assert list(actual) == [
+        '',
+        '.. py:function:: Qux(foo, bar)',
+        '   :module: target.classes',
+        '',
+    ]
+

tests/test_ext_autodoc_autofunction.py

@@ -40,6 +40,14 @@ def test_classes(app):
         '',
     ]
 
+    actual = do_autodoc(app, 'function', 'target.classes.Qux')
+    assert list(actual) == [
+        '',
+        '.. py:function:: Qux(foo, bar)',
+        '   :module: target.classes',
+        '',
+    ]
+
 
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_callable(app):