Import stdlib ABCs from 'collections.abc' rather than 'collections'. (#6451)

On Python 2.7, fall back to 'collections'.

Closes #6450.

Author: tseaver

packages/google-api-core/google/api_core/protobuf_helpers.py

@@ -15,6 +15,10 @@
 """Helpers for :mod:`protobuf`."""
 
 import collections
+try:
+    from collections import abc as collections_abc
+except ImportError:  # Python 2.7
+    import collections as collections_abc
 import copy
 import inspect
 
@@ -161,7 +165,7 @@ def get(msg_or_dict, key, default=_SENTINEL):
     # If we get something else, complain.
     if isinstance(msg_or_dict, message.Message):
         answer = getattr(msg_or_dict, key, default)
-    elif isinstance(msg_or_dict, collections.Mapping):
+    elif isinstance(msg_or_dict, collections_abc.Mapping):
         answer = msg_or_dict.get(key, default)
     else:
         raise TypeError(
@@ -184,21 +188,21 @@ def _set_field_on_message(msg, key, value):
     """Set helper for protobuf Messages."""
     # Attempt to set the value on the types of objects we know how to deal
     # with.
-    if isinstance(value, (collections.MutableSequence, tuple)):
+    if isinstance(value, (collections_abc.MutableSequence, tuple)):
         # Clear the existing repeated protobuf message of any elements
         # currently inside it.
         while getattr(msg, key):
             getattr(msg, key).pop()
 
         # Write our new elements to the repeated field.
         for item in value:
-            if isinstance(item, collections.Mapping):
+            if isinstance(item, collections_abc.Mapping):
                 getattr(msg, key).add(**item)
             else:
                 # protobuf's RepeatedCompositeContainer doesn't support
                 # append.
                 getattr(msg, key).extend([item])
-    elif isinstance(value, collections.Mapping):
+    elif isinstance(value, collections_abc.Mapping):
         # Assign the dictionary values to the protobuf message.
         for item_key, item_value in value.items():
             set(getattr(msg, key), item_key, item_value)
@@ -222,7 +226,7 @@ def set(msg_or_dict, key, value):
     """
     # Sanity check: Is our target object valid?
     if (not isinstance(msg_or_dict,
-                       (collections.MutableMapping, message.Message))):
+                       (collections_abc.MutableMapping, message.Message))):
         raise TypeError(
             'set() expected a dict or protobuf message, got {!r}.'.format(
                 type(msg_or_dict)))
@@ -233,12 +237,12 @@ def set(msg_or_dict, key, value):
     # If a subkey exists, then get that object and call this method
     # recursively against it using the subkey.
     if subkey is not None:
-        if isinstance(msg_or_dict, collections.MutableMapping):
+        if isinstance(msg_or_dict, collections_abc.MutableMapping):
             msg_or_dict.setdefault(basekey, {})
         set(get(msg_or_dict, basekey), subkey, value)
         return
 
-    if isinstance(msg_or_dict, collections.MutableMapping):
+    if isinstance(msg_or_dict, collections_abc.MutableMapping):
         msg_or_dict[key] = value
     else:
         _set_field_on_message(msg_or_dict, key, value)