update_abstractmethods now ignores non-abstract classes

python · gvanrossum · Oct 6, 2020 · Oct 1, 2020 · Oct 1, 2020 · Oct 1, 2020
commit 4f3d8469c2afec3bfcae11b0e6502f8d3c44bf46
diff --git a/Doc/library/abc.rst b/Doc/library/abc.rst
@@ -345,7 +345,7 @@ The :mod:`abc` module also provides the following functions:
 
    If *cls* has any subclasses, raises a :exc:`RuntimeError`.
 
-   If *cls* is not an instance of ABCMeta, raises a :exc:`TypeError`.
+   If *cls* is not an instance of ABCMeta, does nothing.
 
    .. versionadded:: 3.10
 

diff --git a/Lib/abc.py b/Lib/abc.py
@@ -138,14 +138,14 @@ class after this function is called.
 
     If cls is has any subclasses, raises a RuntimeError.
 
-    If cls is not an instance of ABCMeta, raises a TypeError.
+    If cls is not an instance of ABCMeta, does nothing.
     """
     if not hasattr(cls, '__abstractmethods__'):
         # We check for __abstractmethods__ here because cls might by a C
         # implementation or a python implementation (especially during
         # testing), and we want to handle both cases.
-        raise TypeError('cls must be an abstract class or subclass of an abstract'
-                        ' class')
+        return cls
+
     if cls.__subclasses__():
         raise RuntimeError("cannot update abstract methods of class after"
                            " subclassing")

diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
@@ -993,9 +993,7 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen):
         cls.__doc__ = (cls.__name__ +
                        str(inspect.signature(cls)).replace(' -> None', ''))
 
-    # Update the abstract methods of the class, if it is abstract.
-    if isinstance(cls, abc.ABCMeta):
-        abc.update_abstractmethods(cls)
+    abc.update_abstractmethods(cls)
 
     return cls
 

diff --git a/Lib/test/test_abc.py b/Lib/test/test_abc.py
@@ -567,7 +567,9 @@ def updated_foo(self):
                 pass
 
             A.foo = updated_foo
-            self.assertRaises(TypeError, abc.update_abstractmethods, A)
+            abc.update_abstractmethods(A)
+            A()
+            self.assertFalse(hasattr(A, '__abstractmethods__'))
 
 
     class TestABCWithInitSubclass(unittest.TestCase):

diff --git a/Misc/NEWS.d/next/Library/2020-10-01-21-11-03.bpo-41905._JpjR4.rst b/Misc/NEWS.d/next/Library/2020-10-01-21-11-03.bpo-41905._JpjR4.rst
@@ -1 +1 @@
-A new function in abc: *update_abstractmethods* to re-calculate an abstract class's abstract status. In addition, *dataclass* and *total_ordering* have been changed to call this function. Finally, *total_ordering* was patched so that it would override abstract methods.
+A new function in abc: *update_abstractmethods* to re-calculate an abstract class's abstract status. In addition, *dataclass* and *total_ordering* have been changed to call this function. Finally, *total_ordering* was patched so that it would override abstract methods defined in superclasses.
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		A new function in abc: update_abstractmethods to re-calculate an abstract class's abstract status. In addition, dataclass and total_ordering have been changed to call this function. Finally, total_ordering was patched so that it would override abstract methods.
		A new function in abc: update_abstractmethods to re-calculate an abstract class's abstract status. In addition, dataclass and total_ordering have been changed to call this function. Finally, total_ordering was patched so that it would override abstract methods defined in superclasses.