add DocsFromParent

CHANGELOG.md

 # v2.9.10
 
 * semantics of `catch_exception` changed
+* added `DocsFromParent`
+

docs/coding/functions.rst

@@ -43,6 +43,12 @@ You can also decorate given callables in order not to be wrapped with
 .. autofunction:: satella.coding.dont_wrap
 
 
+DocsFromParent
+--------------
+
+.. autoclass:: satella.coding.DocsFromParent
+    :members:
+
 metaclass_maker
 ---------------
 

satella/coding/__init__.py

@@ -10,7 +10,7 @@ from .decorators import precondition, short_none, has_keys, \
 from .deleters import ListDeleter, DictDeleter
 from .fun_static import static_var
 from .iterators import hint_with_length, SelfClosingGenerator, exhaust, chain
-from .metaclasses import metaclass_maker, wrap_with, dont_wrap, wrap_property
+from .metaclasses import metaclass_maker, wrap_with, dont_wrap, wrap_property, DocsFromParent
 from .misc import update_if_not_none
 from .recast_exceptions import rethrow_as, silence_excs, catch_exception, log_exceptions, \
     raises_exception

satella/coding/metaclasses.py

 import inspect
 
+from .recast_exceptions import silence_excs
 from .decorators import wraps
 
 """
@@ -9,7 +10,30 @@ modified
 from abc import ABCMeta
 import typing as tp
 
-__all__ = ['metaclass_maker', 'wrap_with', 'dont_wrap', 'wrap_property']
+__all__ = ['metaclass_maker', 'wrap_with', 'dont_wrap', 'wrap_property',
+           'DocsFromParent']
+
+
+class DocsFromParent(type):
+    """
+    A metaclass that fetches missing docstring's for methods from class's immediate parent
+
+    >>> class Father:
+    >>>     def test(self):
+    >>>         '''my docstring'''
+
+    >>> class Child(Father, metaclass=DocsFromParent):
+    >>>     def test(self):
+    >>>         ...
+    >>> assert Child.test.__doc__ == 'my docstring'
+    """
+    def __call__(cls, name, bases, dictionary):
+        for key, value in dictionary.items():
+            if bases and callable(value) and not value.__doc__:
+                with silence_excs(AttributeError):
+                    value.__doc__ = getattr(bases[0], key).__doc__
+                    dictionary[key] = value
+        return super().__call__(name, bases, dictionary)
 
 
 def skip_redundant(iterable, skip_set=None):

tests/test_coding/test_metaclasses.py

 import abc
 import unittest
 
-from satella.coding import metaclass_maker, wrap_with, dont_wrap, rethrow_as, wrap_property
+from satella.coding import metaclass_maker, wrap_with, dont_wrap, rethrow_as, wrap_property, \
+    DocsFromParent
 
 
 class MetaA(type):
@@ -25,6 +26,18 @@ class AB(A, B, metaclass=metaclass_maker):
 
 
 class TestMetaclasses(unittest.TestCase):
+
+    def test_docs_from_parent(self):
+        class Father:
+            def test(self):
+                """my docstring"""
+
+        class Child(Father, metaclass=DocsFromParent):
+            def test(self):
+                pass
+
+        self.assertEqual(Child.test.__doc, Father.test.__doc__)
+
     def test_metaclasses(self):
         AB()