Switch from 'collections' -> 'collections.abc'

Resolve the following deprecation warnings on Python 3.x:

    DeprecationWarning: 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"

Note that even though we're in Ussuri, I've kept this Python 2
compatible since we haven't done all the other work to mark this
package as Python 3-only.

Change-Id: Iff4cf1871a6a91d91da03d9b79ef61e715a979cf
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

oslo_reports/models/base.py

@@ -21,13 +21,17 @@ store unserialized data generated by generators during
 the report serialization process.
 """
 
-import collections as col
 import copy
 
+try:  # python 3
+    from collections import abc
+except ImportError:  # python 2
+    import collections as abc
+
 import six
 
 
-class ReportModel(col.MutableMapping):
+class ReportModel(abc.MutableMapping):
     """A Report Data Model
 
     A report data model contains data generated by some
@@ -52,9 +56,9 @@ class ReportModel(col.MutableMapping):
         self.attached_view = attached_view
 
         if data is not None:
-            if isinstance(data, col.Mapping):
+            if isinstance(data, abc.Mapping):
                 self.data = dict(data)
-            elif isinstance(data, col.Sequence):
+            elif isinstance(data, abc.Sequence):
                 # convert a list [a, b, c] to a dict {0: a, 1: b, 2: c}
                 self.data = dict(enumerate(data))
             else:
@@ -151,11 +155,11 @@ class ReportModel(col.MutableMapping):
             if hasattr(obj, 'set_current_view_type'):
                 obj.set_current_view_type(tp, visited=visited)
 
-            if isinstance(obj, col.Sequence):
+            if isinstance(obj, abc.Sequence):
                 for item in obj:
                     traverse_obj(item)
 
-            elif isinstance(obj, col.Mapping):
+            elif isinstance(obj, abc.Mapping):
                 for val in six.itervalues(obj):
                     traverse_obj(val)
 

oslo_reports/tests/test_base_report.py

@@ -12,9 +12,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import collections as col
 import re
 
+try:  # python 3
+    from collections import abc
+except ImportError:  # python 2
+    import collections as abc
+
 from oslotest import base
 import six
 
@@ -119,7 +123,7 @@ class TestBaseModel(base.BaseTestCase):
         self.assertEqual('0: a;1: b;', six.text_type(model))
 
     def test_immutable_mappings_produce_mutable_models(self):
-        class SomeImmutableMapping(col.Mapping):
+        class SomeImmutableMapping(abc.Mapping):
             def __init__(self):
                 self.data = {'a': 2, 'b': 4, 'c': 8}
 

oslo_reports/views/text/generic.py

@@ -18,7 +18,10 @@ This modules provides several generic views for
 serializing models into human-readable text.
 """
 
-import collections as col
+try:  # python 3
+    from collections import abc
+except ImportError:  # python 2
+    import collections as abc
 
 import six
 
@@ -112,7 +115,7 @@ class KeyValueView(object):
             if rootkey is not None:
                 res.append((self.indent_str * indent) + rootkey)
 
-            if isinstance(root, col.Mapping):
+            if isinstance(root, abc.Mapping):
                 if rootkey is None and indent > 0:
                     res.append((self.indent_str * indent) + self.anon_dict)
                 elif rootkey is not None:
@@ -122,7 +125,7 @@ class KeyValueView(object):
 
                 for key in sorted(root):
                     res.extend(serialize(root[key], key, indent + 1))
-            elif (isinstance(root, col.Sequence) and
+            elif (isinstance(root, abc.Sequence) and
                     not isinstance(root, six.string_types)):
                 if rootkey is not None:
                     res[0] += self.list_sep

oslo_reports/views/xml/generic.py

@@ -23,10 +23,14 @@ and non-naive serializers check for this attribute and handle
 such strings specially)
 """
 
-import collections as col
 import copy
 import xml.etree.ElementTree as ET
 
+try:  # python 3
+    from collections import abc
+except ImportError:  # python 2
+    import collections as abc
+
 import six
 
 from oslo_reports import _utils as utils
@@ -65,10 +69,10 @@ class KeyValueView(object):
         def serialize(rootmodel, rootkeyname):
             res = ET.Element(rootkeyname)
 
-            if isinstance(rootmodel, col.Mapping):
+            if isinstance(rootmodel, abc.Mapping):
                 for key in sorted(rootmodel):
                     res.append(serialize(rootmodel[key], key))
-            elif (isinstance(rootmodel, col.Sequence) and
+            elif (isinstance(rootmodel, abc.Sequence) and
                     not isinstance(rootmodel, six.string_types)):
                 for val in sorted(rootmodel, key=str):
                     res.append(serialize(val, 'item'))