bpo-25988: Do not expose abstract collection classes in the collectio…

…ns module. (GH-10596)

Doc/whatsnew/3.9.rst

@@ -195,6 +195,11 @@ Deprecated
 Removed
 =======
 
+* The abstract base classes in :mod:`collections.abc` no longer are
+  exposed in the regular :mod:`collections` module.  This will help
+  create a clearer distinction between the concrete classes and the abstract
+  base classes.
+
 * The undocumented ``sys.callstats()`` function has been removed. Since Python
   3.7, it was deprecated and always returned :const:`None`. It required a special
   build option ``CALL_PROFILE`` which was already removed in Python 3.7.

Lib/collections/__init__.py

@@ -39,21 +39,6 @@
     pass
 
 
-def __getattr__(name):
-    # For backwards compatibility, continue to make the collections ABCs
-    # through Python 3.6 available through the collections module.
-    # Note, no new collections ABCs were added in Python 3.7
-    if name in _collections_abc.__all__:
-        obj = getattr(_collections_abc, name)
-        import warnings
-        warnings.warn("Using or importing the ABCs from 'collections' instead "
-                      "of from 'collections.abc' is deprecated since Python 3.3, "
-                      "and in 3.9 it will stop working",
-                      DeprecationWarning, stacklevel=2)
-        globals()[name] = obj
-        return obj
-    raise AttributeError(f'module {__name__!r} has no attribute {name!r}')
-
 ################################################################################
 ### OrderedDict
 ################################################################################

Misc/NEWS.d/next/Library/2018-11-19-10-23-58.bpo-25988.6o7gGK.rst

@@ -0,0 +1,2 @@
+The abstract base classes in :mod:`collections.abc` no longer are exposed in
+the regular :mod:`collections` module.