Update for Python 3.7+

docs/topics/exporters.rst

@@ -205,7 +205,7 @@ BaseItemExporter
 
               ['field1', 'field2']
 
-      -   A dict [3]_ where keys are fields and values are output names::
+      -   A dict where keys are fields and values are output names::
 
               {'field1': 'Field 1', 'field2': 'Field 2'}
 
@@ -214,14 +214,6 @@ BaseItemExporter
              all their possible fields, exporters that do not support exporting
              a different subset of fields per item will only export the fields 
              found in the first item exported.
-      .. [3] Dicts preserve insertion order since `Python 3.7`_
-             (`CPython 3.6`_, `PyPy 2.5`_). If you are using an older version
-             of Python, use an OrderedDict_ to enforce a specific field order.
-
-             .. _Python 3.7: https://docs.python.org/whatsnew/3.7.html
-             .. _CPython 3.6: https://docs.python.org/whatsnew/3.6.html#new-dict-implementation
-             .. _PyPy 2.5: https://morepypy.blogspot.com/2015/02/pypy-250-released.html
-             .. _OrderedDict: https://docs.python.org/library/collections.html#collections.OrderedDict
 
    .. attribute:: export_empty_fields
 

scrapy/exporters.py

@@ -2,13 +2,13 @@
 Item Exporters are used to export/serialize items into different formats.
 """
 
-from collections import Mapping
 import csv
 import io
 import marshal
 import pickle
 import pprint
 import warnings
+from collections.abc import Mapping
 from xml.sax.saxutils import XMLGenerator
 
 from itemadapter import is_item, ItemAdapter

scrapy/settings/__init__.py

@@ -1,6 +1,5 @@
 import json
 import copy
-from collections import OrderedDict
 from collections.abc import MutableMapping
 from importlib import import_module
 from pprint import pformat
@@ -199,7 +198,7 @@ class BaseSettings(MutableMapping):
         return dict(value)
 
     def getdictorlist(self, name, default=None):
-        """Get a setting value as either an ``OrderedDict`` or a list.
+        """Get a setting value as either a :class:`dict` or a :class:`list`.
 
         If the setting is already a dict or a list, a copy of it will be
         returned.
@@ -209,7 +208,7 @@ class BaseSettings(MutableMapping):
 
         For example, settings populated from the command line will return:
 
-        -   ``OrdetedDict([('key1', 'value1'), ('key2', 'value2')])`` if set to
+        -   ``{'key1': 'value1', 'key2': 'value2'}`` if set to
             ``'{"key1": "value1", "key2": "value2"}'``
 
         -   ``['one', 'two']`` if set to ``'["one", "two"]'`` or ``'one,two'``
@@ -222,10 +221,10 @@ class BaseSettings(MutableMapping):
         """
         value = self.get(name, default)
         if value is None:
-            return OrderedDict()
+            return {}
         if isinstance(value, str):
             try:
-                return json.loads(value, object_pairs_hook=OrderedDict)
+                return json.loads(value)
             except ValueError:
                 return value.split(',')
         return copy.deepcopy(value)

tests/test_exporters.py

@@ -4,7 +4,6 @@ import marshal
 import pickle
 import tempfile
 import unittest
-from collections import OrderedDict
 from io import BytesIO
 from datetime import datetime
 from warnings import catch_warnings, filterwarnings
@@ -114,11 +113,11 @@ class BaseItemExporterTest(unittest.TestCase):
         self.assertEqual(name, 'John\xa3')
 
         ie = self._get_exporter(
-            fields_to_export=OrderedDict([('name', u'名稱')])
+            fields_to_export={'name': '名稱'}
         )
         self.assertEqual(
             list(ie._get_serialized_fields(self.i)),
-            [(u'名稱', u'John\xa3')]
+            [('名稱', 'John\xa3')]
         )
 
     def test_field_custom_serializer(self):

tests/test_feedexport.py

@@ -11,7 +11,7 @@ import sys
 import tempfile
 import warnings
 from abc import ABC, abstractmethod
-from collections import defaultdict, OrderedDict
+from collections import defaultdict
 from contextlib import ExitStack
 from io import BytesIO
 from logging import getLogger
@@ -998,9 +998,7 @@ class FeedExportTest(FeedExportTestBase):
     @defer.inlineCallbacks
     def test_export_items_field_names(self):
         items = [{'foo': 'bar'}]
-        header = OrderedDict((
-            ("foo", "Foo"),
-        ))
+        header = {'foo': 'Foo'}
         rows = [{'Foo': 'bar'}]
         settings = {'FEED_EXPORT_FIELDS': header}
         yield self.assertExported(items, list(header.values()), rows,
@@ -1023,9 +1021,7 @@ class FeedExportTest(FeedExportTestBase):
     @defer.inlineCallbacks
     def test_export_items_json_field_names(self):
         items = [{'foo': 'bar'}]
-        header = OrderedDict((
-            ("foo", "Foo"),
-        ))
+        header = {'foo': 'Foo'}
         rows = [{'Foo': 'bar'}]
         settings = {'FEED_EXPORT_FIELDS': json.dumps(header)}
         yield self.assertExported(items, list(header.values()), rows,