remove drop_dups index option, deprecated with MongoDB3

docs/changelog.rst

@@ -10,8 +10,10 @@ Development
 - Fixed a bug causing inaccurate query results, while combining ``__raw__`` and regular filters for the same field #2264
 - Add support for the `elemMatch` projection operator in .fields() (e.g BlogPost.objects.fields(elemMatch__comments="test")) #2267
 - DictField validate failed without default connection (bug introduced in 0.19.0) #2239
-- Remove name parameter in Field constructor e.g `StringField(name="...")`, it was deprecated a while ago in favor of db_field
-- Remove method queryset.slave_okay() that was deprecated a while ago and disappeared since pymongo3
+- Remove methods deprecated years ago:
+    - name parameter in Field constructor e.g `StringField(name="...")`, was replaced by db_field
+    - Queryset.slave_okay() was deprecated since pymongo3
+    - dropDups was dropped with MongoDB3
 
 Changes in 0.19.1
 =================

docs/guide/defining-documents.rst

@@ -555,7 +555,6 @@ There are a few top level defaults for all indexes that can be set::
             'index_background': True,
             'index_cls': False,
             'auto_create_index': True,
-            'index_drop_dups': True,
         }
 
 
@@ -574,11 +573,6 @@ There are a few top level defaults for all indexes that can be set::
     in systems where indexes are managed separately. Disabling this will improve
     performance.
 
-:attr:`index_drop_dups` (Optional)
-    Set the default value for if an index should drop duplicates
-    Since MongoDB 3.0 drop_dups is not supported anymore. Raises a Warning
-    and has no effect
-
 
 Compound Indexes and Indexing sub documents
 -------------------------------------------

mongoengine/base/metaclasses.py

@@ -284,7 +284,6 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
                 "indexes": [],  # indexes to be ensured at runtime
                 "id_field": None,
                 "index_background": False,
-                "index_drop_dups": False,
                 "index_opts": None,
                 "delete_rules": None,
                 # allow_inheritance can be True, False, and None. True means

mongoengine/document.py

@@ -851,17 +851,13 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
         index_spec = cls._build_index_spec(keys)
         index_spec = index_spec.copy()
         fields = index_spec.pop("fields")
-        drop_dups = kwargs.get("drop_dups", False)
-        if drop_dups:
-            msg = "drop_dups is deprecated and is removed when using PyMongo 3+."
-            warnings.warn(msg, DeprecationWarning)
         index_spec["background"] = background
         index_spec.update(kwargs)
 
         return cls._get_collection().create_index(fields, **index_spec)
 
     @classmethod
-    def ensure_index(cls, key_or_list, drop_dups=False, background=False, **kwargs):
+    def ensure_index(cls, key_or_list, background=False, **kwargs):
         """Ensure that the given indexes are in place. Deprecated in favour
         of create_index.
 
@@ -869,12 +865,7 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
             construct a multi-field index); keys may be prefixed with a **+**
             or a **-** to determine the index ordering
         :param background: Allows index creation in the background
-        :param drop_dups: Was removed/ignored with MongoDB >2.7.5. The value
-            will be removed if PyMongo3+ is used
         """
-        if drop_dups:
-            msg = "drop_dups is deprecated and is removed when using PyMongo 3+."
-            warnings.warn(msg, DeprecationWarning)
         return cls.create_index(key_or_list, background=background, **kwargs)
 
     @classmethod
@@ -887,12 +878,8 @@ class Document(six.with_metaclass(TopLevelDocumentMetaclass, BaseDocument)):
                   `auto_create_index` to False in the documents meta data
         """
         background = cls._meta.get("index_background", False)
-        drop_dups = cls._meta.get("index_drop_dups", False)
         index_opts = cls._meta.get("index_opts") or {}
         index_cls = cls._meta.get("index_cls", True)
-        if drop_dups:
-            msg = "drop_dups is deprecated and is removed when using PyMongo 3+."
-            warnings.warn(msg, DeprecationWarning)
 
         collection = cls._get_collection()
         # 746: when connection is via mongos, the read preference is not necessarily an indication that

tests/document/test_indexes.py

@@ -806,18 +806,6 @@ class TestIndexes(unittest.TestCase):
         info = Log.objects._collection.index_information()
         assert 3600 == info["created_1"]["expireAfterSeconds"]
 
-    def test_index_drop_dups_silently_ignored(self):
-        class Customer(Document):
-            cust_id = IntField(unique=True, required=True)
-            meta = {
-                "indexes": ["cust_id"],
-                "index_drop_dups": True,
-                "allow_inheritance": False,
-            }
-
-        Customer.drop_collection()
-        Customer.objects.first()
-
     def test_unique_and_indexes(self):
         """Ensure that 'unique' constraints aren't overridden by
         meta.indexes.
@@ -1058,10 +1046,6 @@ class TestIndexes(unittest.TestCase):
                 del index_info[key][
                     "ns"
                 ]  # drop the index namespace - we don't care about that here, MongoDB 3+
-            if "dropDups" in index_info[key]:
-                del index_info[key][
-                    "dropDups"
-                ]  # drop the index dropDups - it is deprecated in MongoDB 3+
 
         assert index_info == {
             "txt_1": {"key": [("txt", 1)], "background": False},

tests/document/test_inheritance.py

@@ -523,7 +523,6 @@ class TestInheritance(MongoDBTestCase):
 
         defaults = {
             "index_background": True,
-            "index_drop_dups": True,
             "index_opts": {"hello": "world"},
             "allow_inheritance": True,
             "queryset_class": "QuerySet",