Drop python2 support

.travis.yml

@@ -1,13 +1,10 @@
 # For full coverage, we'd have to test all supported Python, MongoDB, and
 # PyMongo combinations. However, that would result in an overly long build
 # with a very large number of jobs, hence we only test a subset of all the
-# combinations:
+# combinations.
-# * MongoDB v3.4 & the latest PyMongo v3.x is currently the "main" setup,
+# * Python3.7, MongoDB v3.4 & the latest PyMongo v3.x is currently the "main" setup,
-#   tested against Python v2.7, v3.5, v3.6, v3.7, v3.8, PyPy and PyPy3.
+# Other combinations are tested. See below for the details or check the travis jobs
-# * Besides that, we test the lowest actively supported Python/MongoDB/PyMongo
+
-#   combination: MongoDB v3.4, PyMongo v3.4, Python v2.7.
-# * MongoDB v3.6 is tested against Python v3.6, and PyMongo v3.6, v3.7, v3.8.
-#
 # We should periodically check MongoDB Server versions supported by MongoDB
 # Inc., add newly released versions to the test matrix, and remove versions
 # which have reached their End of Life. See:
@@ -16,21 +13,15 @@
 #
 # Reminder: Update README.rst if you change MongoDB versions we test.
 
-
 language: python
+dist: xenial
 python:
-- 2.7
 - 3.5
 - 3.6
 - 3.7
 - 3.8
-- pypy
 - pypy3
 
-dist: xenial
-
-dist: xenial
-
 env:
   global:
     - MONGODB_3_4=3.4.17
@@ -41,6 +32,8 @@ env:
     - PYMONGO_3_6=3.6
     - PYMONGO_3_9=3.9
     - PYMONGO_3_10=3.10
+
+    - MAIN_PYTHON_VERSION = "3.7"
   matrix:
     - MONGODB=${MONGODB_3_4} PYMONGO=${PYMONGO_3_10}
 
@@ -49,8 +42,6 @@ matrix:
   fast_finish: true
 
   include:
-  - python: 2.7
-    env: MONGODB=${MONGODB_3_4} PYMONGO=${PYMONGO_3_4}
   - python: 3.7
     env: MONGODB=${MONGODB_3_6} PYMONGO=${PYMONGO_3_6}
   - python: 3.7
@@ -74,20 +65,20 @@ install:
   # tox dryrun to setup the tox venv (we run a mock test).
   - tox -e $(echo py$TRAVIS_PYTHON_VERSION-mg$PYMONGO | tr -d . | sed -e 's/pypypy/pypy/') -- -a "-k=test_ci_placeholder"
   # Install black for Python v3.7 only.
-  - if [[ $TRAVIS_PYTHON_VERSION == '3.7' ]]; then pip install black; fi
+  - if [[ $TRAVIS_PYTHON_VERSION == $MAIN_PYTHON_VERSION ]]; then pip install black; fi
 
 before_script:
   - mkdir ${PWD}/mongodb-linux-x86_64-${MONGODB}/data
   - ${PWD}/mongodb-linux-x86_64-${MONGODB}/bin/mongod --dbpath ${PWD}/mongodb-linux-x86_64-${MONGODB}/data --logpath ${PWD}/mongodb-linux-x86_64-${MONGODB}/mongodb.log --fork
-  - if [[ $TRAVIS_PYTHON_VERSION == '3.7' ]]; then flake8 .; else echo "flake8 only runs on py37"; fi         # Run flake8 for Python 3.7 only
+  - if [[ $TRAVIS_PYTHON_VERSION == $MAIN_PYTHON_VERSION ]]; then flake8 .; else echo "flake8 only runs on py37"; fi
-  - if [[ $TRAVIS_PYTHON_VERSION == '3.7' ]]; then black --check .; else echo "black only runs on py37"; fi   # Run black for Python 3.7 only
+  - if [[ $TRAVIS_PYTHON_VERSION == $MAIN_PYTHON_VERSION ]]; then black --check .; else echo "black only runs on py37"; fi
   - mongo --eval 'db.version();'    # Make sure mongo is awake
 
 script:
   - tox -e $(echo py$TRAVIS_PYTHON_VERSION-mg$PYMONGO | tr -d . | sed -e 's/pypypy/pypy/') -- -a "--cov=mongoengine"
 
 after_success:
-- coveralls --verbose
+- - if [[ $TRAVIS_PYTHON_VERSION == $MAIN_PYTHON_VERSION ]]; then coveralls --verbose; else echo "coveralls only sent for py37"; fi
 
 notifications:
   irc: irc.freenode.org#mongoengine
@@ -109,11 +100,11 @@ deploy:
   distributions: "sdist bdist_wheel"
 
   # Only deploy on tagged commits (aka GitHub releases) and only for the parent
-  # repo's builds running Python v2.7 along with PyMongo v3.x and MongoDB v3.4.
+  # repo's builds running Python v3.7 along with PyMongo v3.x and MongoDB v3.4.
   # We run Travis against many different Python, PyMongo, and MongoDB versions
   # and we don't want the deploy to occur multiple times).
   on:
     tags: true
     repo: MongoEngine/mongoengine
     condition: ($PYMONGO = ${PYMONGO_3_10}) && ($MONGODB = ${MONGODB_3_4})
-    python: 2.7
+    python: 3.7

CONTRIBUTING.rst

@@ -20,23 +20,23 @@ post to the `user group <http://groups.google.com/group/mongoengine-users>`
 Supported Interpreters
 ----------------------
 
-MongoEngine supports CPython 2.7 and newer. Language
+MongoEngine supports CPython 3.7 and newer as well as Pypy3.
-features not supported by all interpreters can not be used.
+Language features not supported by all interpreters can not be used.
 
-Python 2/3 compatibility
+Python3 codebase
 ----------------------
 
-The codebase is written in a compatible manner for python 2 & 3 so it
+Since 0.20, the codebase is exclusively Python 3.
-is important that this is taken into account when it comes to discrepencies
+
-between the two versions (see https://python-future.org/compatible_idioms.html).
+Earlier versions were exclusively Python2, and was relying on 2to3 to support Python3 installs.
-Travis runs the tests against different Python versions as a safety net.
+Travis runs the tests against the main Python 3.x versions.
 
 
 Style Guide
 -----------
 
-MongoEngine uses `black <https://github.com/python/black>`_ for code
+MongoEngine uses `black <https://github.com/python/black>`_ for code formatting.
-formatting.
+Black runs as part of the CI so it will fail in case the code is not formatted properly.
 
 Testing
 -------

benchmarks/test_inserts.py

@@ -3,8 +3,6 @@ import timeit
 
 def main():
     setup = """
-from builtins import range
-
 from pymongo import MongoClient
 
 connection = MongoClient()
@@ -59,8 +57,6 @@ myNoddys = noddy.find()
     print("{}s".format(t.timeit(1)))
 
     setup = """
-from builtins import range
-
 from pymongo import MongoClient
 
 connection = MongoClient()

mongoengine/base/datastructures.py

@@ -1,7 +1,6 @@
 import weakref
 
 from bson import DBRef
-from future.utils import listitems
 import six
 from six import iteritems
 
@@ -181,19 +180,6 @@ class BaseList(list):
     __iadd__ = mark_as_changed_wrapper(list.__iadd__)
     __imul__ = mark_as_changed_wrapper(list.__imul__)
 
-    if six.PY2:
-        # Under py3 __setslice__, __delslice__ and __getslice__
-        # are replaced by __setitem__, __delitem__ and __getitem__ with a slice as parameter
-        # so we mimic this under python 2
-        def __setslice__(self, i, j, sequence):
-            return self.__setitem__(slice(i, j), sequence)
-
-        def __delslice__(self, i, j):
-            return self.__delitem__(slice(i, j))
-
-        def __getslice__(self, i, j):
-            return self.__getitem__(slice(i, j))
-
     def _mark_as_changed(self, key=None):
         if hasattr(self._instance, "_mark_as_changed"):
             if key:
@@ -426,7 +412,7 @@ class StrictDict(object):
         return len(list(iteritems(self)))
 
     def __eq__(self, other):
-        return listitems(self) == listitems(other)
+        return list(self.items()) == list(other.items())
 
     def __ne__(self, other):
         return not (self == other)

mongoengine/base/document.py

@@ -1,9 +1,9 @@
 import copy
+
 import numbers
 from functools import partial
 
 from bson import DBRef, ObjectId, SON, json_util
-from future.utils import listitems
 import pymongo
 import six
 from six import iteritems
@@ -26,7 +26,6 @@ from mongoengine.errors import (
     OperationError,
     ValidationError,
 )
-from mongoengine.python_support import Hashable
 
 __all__ = ("BaseDocument", "NON_FIELD_ERRORS")
 
@@ -294,10 +293,7 @@ class BaseDocument(object):
     def __str__(self):
         # TODO this could be simpler?
         if hasattr(self, "__unicode__"):
-            if six.PY3:
+            return self.__unicode__()
-                return self.__unicode__()
-            else:
-                return six.text_type(self).encode("utf-8")
         return six.text_type("%s object" % self.__class__.__name__)
 
     def __eq__(self, other):
@@ -671,7 +667,7 @@ class BaseDocument(object):
                 del set_data["_id"]
 
         # Determine if any changed items were actually unset.
-        for path, value in listitems(set_data):
+        for path, value in list(set_data.items()):
             if value or isinstance(
                 value, (numbers.Number, bool)
             ):  # Account for 0 and True that are truthy

mongoengine/fields.py

@@ -5,12 +5,12 @@ import re
 import socket
 import time
 import uuid
+from io import BytesIO
 from operator import itemgetter
 
 from bson import Binary, DBRef, ObjectId, SON
 from bson.int64 import Int64
 import gridfs
-from past.builtins import long
 import pymongo
 from pymongo import ReturnDocument
 import six
@@ -39,7 +39,6 @@ from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.document import Document, EmbeddedDocument
 from mongoengine.errors import DoesNotExist, InvalidQueryError, ValidationError
 from mongoengine.mongodb_support import MONGODB_36, get_mongodb_version
-from mongoengine.python_support import StringIO
 from mongoengine.queryset import DO_NOTHING
 from mongoengine.queryset.base import BaseQuerySet
 from mongoengine.queryset.transform import STRING_OPERATORS
@@ -338,7 +337,7 @@ class IntField(BaseField):
 
 
 class LongField(BaseField):
-    """64-bit integer field."""
+    """64-bit integer field. (Equivalent to IntField since the support to Python2 was dropped)"""
 
     def __init__(self, min_value=None, max_value=None, **kwargs):
         self.min_value, self.max_value = min_value, max_value
@@ -346,7 +345,7 @@ class LongField(BaseField):
 
     def to_python(self, value):
         try:
-            value = long(value)
+            value = int(value)
         except (TypeError, ValueError):
             pass
         return value
@@ -356,7 +355,7 @@ class LongField(BaseField):
 
     def validate(self, value):
         try:
-            value = long(value)
+            value = int(value)
         except (TypeError, ValueError):
             self.error("%s could not be converted to long" % value)
 
@@ -370,7 +369,7 @@ class LongField(BaseField):
         if value is None:
             return value
 
-        return super(LongField, self).prepare_query_value(op, long(value))
+        return super(LongField, self).prepare_query_value(op, int(value))
 
 
 class FloatField(BaseField):
@@ -1679,8 +1678,6 @@ class GridFSProxy(object):
     def __bool__(self):
         return bool(self.grid_id)
 
-    __nonzero__ = __bool__  # For Py2 support
-
     def __getstate__(self):
         self_dict = self.__dict__
         self_dict["_fs"] = None
@@ -1952,7 +1949,7 @@ class ImageGridFsProxy(GridFSProxy):
 
         w, h = img.size
 
-        io = StringIO()
+        io = BytesIO()
         img.save(io, img_format, progressive=progressive)
         io.seek(0)
 
@@ -1971,7 +1968,7 @@ class ImageGridFsProxy(GridFSProxy):
     def _put_thumbnail(self, thumbnail, format, progressive, **kwargs):
         w, h = thumbnail.size
 
-        io = StringIO()
+        io = BytesIO()
         thumbnail.save(io, format, progressive=progressive)
         io.seek(0)
 

mongoengine/python_support.py

@@ -1,23 +0,0 @@
-"""
-Helper functions, constants, and types to aid with Python v2.7 - v3.x support
-"""
-import six
-
-# six.BytesIO resolves to StringIO.StringIO in Py2 and io.BytesIO in Py3.
-StringIO = six.BytesIO
-
-# Additionally for Py2, try to use the faster cStringIO, if available
-if not six.PY3:
-    try:
-        import cStringIO
-    except ImportError:
-        pass
-    else:
-        StringIO = cStringIO.StringIO
-
-
-if six.PY3:
-    from collections.abc import Hashable
-else:
-    # raises DeprecationWarnings in Python >=3.7
-    from collections import Hashable

mongoengine/queryset/base.py

@@ -1,5 +1,3 @@
-from __future__ import absolute_import
-
 import copy
 import itertools
 import re
@@ -204,8 +202,6 @@ class BaseQuerySet(object):
         """Avoid to open all records in an if stmt in Py3."""
         return self._has_data()
 
-    __nonzero__ = __bool__  # For Py2 support
-
     # Core functions
 
     def all(self):

mongoengine/queryset/field_list.py

@@ -69,8 +69,6 @@ class QueryFieldList(object):
     def __bool__(self):
         return bool(self.fields)
 
-    __nonzero__ = __bool__  # For Py2 support
-
     def as_dict(self):
         field_list = {field: self.value for field in self.fields}
         if self.slice:

mongoengine/queryset/transform.py

@@ -10,7 +10,7 @@ from mongoengine.base import UPDATE_OPERATORS
 from mongoengine.common import _import_class
 from mongoengine.errors import InvalidQueryError
 
-__all__ = ("query", "update")
+__all__ = ("query", "update", "STRING_OPERATORS")
 
 COMPARISON_OPERATORS = (
     "ne",

mongoengine/queryset/visitor.py

@@ -143,8 +143,6 @@ class QCombination(QNode):
     def __bool__(self):
         return bool(self.children)
 
-    __nonzero__ = __bool__  # For Py2 support
-
     def accept(self, visitor):
         for i in range(len(self.children)):
             if isinstance(self.children[i], QNode):
@@ -180,8 +178,6 @@ class Q(QNode):
     def __bool__(self):
         return bool(self.query)
 
-    __nonzero__ = __bool__  # For Py2 support
-
     def __eq__(self, other):
         return self.__class__ == other.__class__ and self.query == other.query
 

setup.py

@@ -110,7 +110,6 @@ CLASSIFIERS = [
 
 PYTHON_VERSION = sys.version_info[0]
 PY3 = PYTHON_VERSION == 3
-PY2 = PYTHON_VERSION == 2
 
 extra_opts = {
     "packages": find_packages(exclude=["tests", "tests.*"]),
@@ -124,14 +123,11 @@ extra_opts = {
     ],
 }
 
-if PY3:
+if "test" in sys.argv:
-    if "test" in sys.argv:
+    extra_opts["packages"] = find_packages()
-        extra_opts["packages"] = find_packages()
+    extra_opts["package_data"] = {
-        extra_opts["package_data"] = {
+        "tests": ["fields/mongoengine.png", "fields/mongodb_leaf.png"]
-            "tests": ["fields/mongoengine.png", "fields/mongodb_leaf.png"]
+    }
-        }
-else:
-    extra_opts["tests_require"] += ["python-dateutil"]
 
 setup(
     name="mongoengine",
@@ -148,7 +144,8 @@ setup(
     long_description=LONG_DESCRIPTION,
     platforms=["any"],
     classifiers=CLASSIFIERS,
-    install_requires=["pymongo>=3.4, <4.0", "six>=1.10.0", "future"],
+    python_requires=">=3.5",
+    install_requires=["pymongo>=3.4, <4.0", "six>=1.10.0"],
     cmdclass={"test": PyTest},
     **extra_opts
 )

tests/fields/test_binary_field.py

@@ -123,10 +123,7 @@ class TestBinaryField(MongoDBTestCase):
             upsert=True, new=True, set__bin_field=BIN_VALUE
         )
         assert doc.some_field == "test"
-        if six.PY3:
+        assert doc.bin_field == BIN_VALUE
-            assert doc.bin_field == BIN_VALUE
-        else:
-            assert doc.bin_field == Binary(BIN_VALUE)
 
     def test_update_one(self):
         """Ensures no regression of bug #1127"""
@@ -144,7 +141,4 @@ class TestBinaryField(MongoDBTestCase):
         )
         assert n_updated == 1
         fetched = MyDocument.objects.with_id(doc.id)
-        if six.PY3:
+        assert fetched.bin_field == BIN_VALUE
-            assert fetched.bin_field == BIN_VALUE
-        else:
-            assert fetched.bin_field == Binary(BIN_VALUE)

tests/fields/test_embedded_document_field.py

@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from builtins import str
-
 import pytest
 
 from mongoengine import (

tests/fields/test_file_field.py

@@ -3,6 +3,7 @@ import copy
 import os
 import tempfile
 import unittest
+from io import BytesIO
 
 import gridfs
 import pytest
@@ -10,7 +11,6 @@ import six
 
 from mongoengine import *
 from mongoengine.connection import get_db
-from mongoengine.python_support import StringIO
 
 try:
     from PIL import Image
@@ -30,7 +30,7 @@ TEST_IMAGE2_PATH = os.path.join(os.path.dirname(__file__), "mongodb_leaf.png")
 def get_file(path):
     """Use a BytesIO instead of a file to allow
     to have a one-liner and avoid that the file remains opened"""
-    bytes_io = StringIO()
+    bytes_io = BytesIO()
     with open(path, "rb") as f:
         bytes_io.write(f.read())
     bytes_io.seek(0)
@@ -80,7 +80,7 @@ class TestFileField(MongoDBTestCase):
         PutFile.drop_collection()
 
         putfile = PutFile()
-        putstring = StringIO()
+        putstring = BytesIO()
         putstring.write(text)
         putstring.seek(0)
         putfile.the_file.put(putstring, content_type=content_type)

tests/fields/test_url_field.py

@@ -1,6 +1,4 @@
 # -*- coding: utf-8 -*-
-from builtins import str
-
 import pytest
 
 from mongoengine import *

tests/queryset/test_queryset.py

@@ -4470,10 +4470,7 @@ class TestQueryset(unittest.TestCase):
 
         pks = self.Person.objects.order_by("age").scalar("pk")[1:3]
         names = self.Person.objects.scalar("name").in_bulk(list(pks)).values()
-        if six.PY3:
+        expected = "['A1', 'A2']"
-            expected = "['A1', 'A2']"
-        else:
-            expected = "[u'A1', u'A2']"
         assert expected == "%s" % sorted(names)
 
     def test_elem_match(self):

tests/test_datastructures.py

@@ -287,7 +287,7 @@ class TestBaseList:
         base_list[:] = [
             0,
             1,
-        ]  # Will use __setslice__ under py2 and __setitem__ under py3
+        ]
         assert base_list._instance._changed_fields == ["my_name"]
         assert base_list == [0, 1]
 
@@ -296,13 +296,13 @@ class TestBaseList:
         base_list[0:2] = [
             1,
             0,
-        ]  # Will use __setslice__ under py2 and __setitem__ under py3
+        ]
         assert base_list._instance._changed_fields == ["my_name"]
         assert base_list == [1, 0, 2]
 
     def test___setitem___calls_with_step_slice_mark_as_changed(self):
         base_list = self._get_baselist([0, 1, 2])
-        base_list[0:3:2] = [-1, -2]  # uses __setitem__ in both py2 & 3
+        base_list[0:3:2] = [-1, -2]  # uses __setitem__
         assert base_list._instance._changed_fields == ["my_name"]
         assert base_list == [-1, 1, -2]
 

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = {py27,py35,pypy,pypy3}-{mg34,mg36,mg39,mg310}
+envlist = {py35,pypy3}-{mg34,mg36,mg39,mg310}
 
 [testenv]
 commands =