Better management of the automatic "_cls" field (#2112)
* Rename BaseQuerySet._initial_query to BaseQuerySet._cls_query
This new name more accurately reflects the purpose of the dict. It is either
empty for documents that don't use inheritance or it contains a `{"_cls": ...}`
shape query. There was nothing "initial" about it per se.
* Drop read_preference as a kwarg on BaseQuerySet.__call__/filter
It was a poor design choice to offer two different ways to do the same thing:
1. `SomeDoc.objects(foo=bar, bar=baz).read_preference(...)`
2. `SomeDoc.objects(foo=bar, bar=baz, read_preference=...)`
Option 1 is good because it's immediately obvious which part defines the query
to be used and which part defines the read preference.
Option 2 is bad because you don't immediately know whether `read_preference`
is a query kwarg or a reserved keyword with some special behavior. If you
wanted to be particularly cruel, you could even write
`SomeDoc.objects(foo=bar, read_preference=..., bar=baz)`.
THIS IS A BREAKING CHANGE. From now on you have to use the
`BaseQuerySet.read_preference(...)` method.
* Add a BaseQuerySet.clear_cls_query method + get rid of the class_check kwarg
This is similar to what the previous commit did to read preference except that
in this case we were still missing a `BaseQuerySet` method for clearing the
`_cls` query.
Now, instead of the undocumented, untested, and confusing interface:
`ParentDoc.objects(foo=bar, bar=baz, class_check=False)`
We do:
`ParentDoc.objects(foo=bar, bar=baz).clear_cls_query()`
This commit is contained in:
Stefan Wójcik
GitHub
parent
bbed312bdd
commit
50555ec73e
@ -6,6 +6,10 @@ Changelog
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Development
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===========
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- (Fill this out as you fix issues and develop your features).
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- BREAKING CHANGE: `class_check` and `read_preference` keyword arguments are no longer available when filtering a `QuerySet`. #2112
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- Instead of `Doc.objects(foo=bar, read_preference=...)` use `Doc.objects(foo=bar).read_preference(...)`.
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- Instead of `Doc.objects(foo=bar, class_check=False)` use `Doc.objects(foo=bar).clear_cls_query(...)`.
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- This change also renames the private `QuerySet._initial_query` attribute to `_cls_query`.
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- BREAKING CHANGE: Removed the deprecated `format` param from `QuerySet.explain` #2113
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- BREAKING CHANGE: Renamed `MongoEngineConnectionError` to `ConnectionFailure` #2111
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- If you catch/use `MongoEngineConnectionError` in your code, you'll have to rename it.
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@ -53,13 +53,12 @@ class BaseQuerySet(object):
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self._collection_obj = collection
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self._mongo_query = None
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self._query_obj = Q()
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self._initial_query = {}
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self._cls_query = {}
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self._where_clause = None
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self._loaded_fields = QueryFieldList()
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self._ordering = None
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self._snapshot = False
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self._timeout = True
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self._class_check = True
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self._slave_okay = False
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self._read_preference = None
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self._iter = False
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@ -72,9 +71,9 @@ class BaseQuerySet(object):
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# subclasses of the class being used
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if document._meta.get("allow_inheritance") is True:
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if len(self._document._subclasses) == 1:
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self._initial_query = {"_cls": self._document._subclasses[0]}
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self._cls_query = {"_cls": self._document._subclasses[0]}
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else:
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self._initial_query = {"_cls": {"$in": self._document._subclasses}}
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self._cls_query = {"_cls": {"$in": self._document._subclasses}}
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self._loaded_fields = QueryFieldList(always_include=["_cls"])
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self._cursor_obj = None
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@ -86,23 +85,19 @@ class BaseQuerySet(object):
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self._max_time_ms = None
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self._comment = None
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def __call__(self, q_obj=None, class_check=True, read_preference=None, **query):
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def __call__(self, q_obj=None, **query):
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"""Filter the selected documents by calling the
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:class:`~mongoengine.queryset.QuerySet` with a query.
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:param q_obj: a :class:`~mongoengine.queryset.Q` object to be used in
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the query; the :class:`~mongoengine.queryset.QuerySet` is filtered
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multiple times with different :class:`~mongoengine.queryset.Q`
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objects, only the last one will be used
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:param class_check: If set to False bypass class name check when
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querying collection
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:param read_preference: if set, overrides connection-level
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read_preference from `ReplicaSetConnection`.
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:param query: Django-style query keyword arguments
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objects, only the last one will be used.
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:param query: Django-style query keyword arguments.
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"""
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query = Q(**query)
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if q_obj:
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# make sure proper query object is passed
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# Make sure proper query object is passed.
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if not isinstance(q_obj, QNode):
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msg = (
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"Not a query object: %s. "
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@ -111,16 +106,10 @@ class BaseQuerySet(object):
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raise InvalidQueryError(msg)
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query &= q_obj
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if read_preference is None:
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queryset = self.clone()
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else:
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# Use the clone provided when setting read_preference
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queryset = self.read_preference(read_preference)
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queryset = self.clone()
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queryset._query_obj &= query
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queryset._mongo_query = None
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queryset._cursor_obj = None
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queryset._class_check = class_check
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return queryset
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@ -222,8 +211,7 @@ class BaseQuerySet(object):
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return self.__call__()
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def filter(self, *q_objs, **query):
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"""An alias of :meth:`~mongoengine.queryset.QuerySet.__call__`
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"""
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"""An alias of :meth:`~mongoengine.queryset.QuerySet.__call__`"""
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return self.__call__(*q_objs, **query)
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def search_text(self, text, language=None):
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@ -743,7 +731,7 @@ class BaseQuerySet(object):
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Do NOT return any inherited documents.
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"""
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if self._document._meta.get("allow_inheritance") is True:
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self._initial_query = {"_cls": self._document._class_name}
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self._cls_query = {"_cls": self._document._class_name}
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return self
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@ -777,7 +765,7 @@ class BaseQuerySet(object):
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copy_props = (
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"_mongo_query",
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"_initial_query",
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"_cls_query",
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"_none",
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"_query_obj",
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"_where_clause",
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@ -785,7 +773,6 @@ class BaseQuerySet(object):
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"_ordering",
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"_snapshot",
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"_timeout",
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"_class_check",
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"_slave_okay",
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"_read_preference",
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"_iter",
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@ -1100,6 +1087,20 @@ class BaseQuerySet(object):
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return queryset
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def clear_cls_query(self):
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"""Clear the default "_cls" query.
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By default, all queries generated for documents that allow inheritance
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include an extra "_cls" clause. In most cases this is desirable, but
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sometimes you might achieve better performance if you clear that
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default query.
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Scan the code for `_cls_query` to get more details.
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"""
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queryset = self.clone()
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queryset._cls_query = {}
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return queryset
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def comment(self, text):
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"""Add a comment to the query.
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@ -1651,13 +1652,11 @@ class BaseQuerySet(object):
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def _query(self):
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if self._mongo_query is None:
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self._mongo_query = self._query_obj.to_query(self._document)
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if self._class_check and self._initial_query:
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if self._cls_query:
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if "_cls" in self._mongo_query:
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self._mongo_query = {
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"$and": [self._initial_query, self._mongo_query]
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}
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self._mongo_query = {"$and": [self._cls_query, self._mongo_query]}
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else:
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self._mongo_query.update(self._initial_query)
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self._mongo_query.update(self._cls_query)
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return self._mongo_query
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@property
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@ -4588,6 +4588,44 @@ class QuerySetTest(unittest.TestCase):
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doc.save()
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self.assertEqual(MyDoc.objects.only("test__47").get().test["47"], 1)
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def test_clear_cls_query(self):
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class Parent(Document):
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name = StringField()
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meta = {"allow_inheritance": True}
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class Child(Parent):
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age = IntField()
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Parent.drop_collection()
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# Default query includes the "_cls" check.
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self.assertEqual(
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Parent.objects._query, {"_cls": {"$in": ("Parent", "Parent.Child")}}
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)
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# Clearing the "_cls" query should work.
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self.assertEqual(Parent.objects.clear_cls_query()._query, {})
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# Clearing the "_cls" query should not persist across queryset instances.
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self.assertEqual(
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Parent.objects._query, {"_cls": {"$in": ("Parent", "Parent.Child")}}
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)
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# The rest of the query should not be cleared.
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self.assertEqual(
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Parent.objects.filter(name="xyz").clear_cls_query()._query, {"name": "xyz"}
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)
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Parent.objects.create(name="foo")
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Child.objects.create(name="bar", age=1)
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self.assertEqual(Parent.objects.clear_cls_query().count(), 2)
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self.assertEqual(Parent.objects.count(), 2)
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self.assertEqual(Child.objects().count(), 1)
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# XXX This isn't really how you'd want to use `clear_cls_query()`, but
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# it's a decent test to validate its behavior nonetheless.
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self.assertEqual(Child.objects.clear_cls_query().count(), 2)
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def test_read_preference(self):
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class Bar(Document):
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txt = StringField()
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@ -4595,40 +4633,35 @@ class QuerySetTest(unittest.TestCase):
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meta = {"indexes": ["txt"]}
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Bar.drop_collection()
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bars = list(Bar.objects(read_preference=ReadPreference.PRIMARY))
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self.assertEqual([], bars)
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bar = Bar.objects.create(txt="xyz")
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self.assertRaises(TypeError, Bar.objects, read_preference="Primary")
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bars = list(Bar.objects.read_preference(ReadPreference.PRIMARY))
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self.assertEqual(bars, [bar])
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# read_preference as a kwarg
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bars = Bar.objects(read_preference=ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(bars._read_preference, ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(
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bars._cursor._Cursor__read_preference, ReadPreference.SECONDARY_PREFERRED
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)
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# read_preference as a query set method
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bars = Bar.objects.read_preference(ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(bars._read_preference, ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(
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bars._cursor._Cursor__read_preference, ReadPreference.SECONDARY_PREFERRED
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)
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# read_preference after skip
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# Make sure that `.read_preference(...)` does accept string values.
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self.assertRaises(TypeError, Bar.objects.read_preference, "Primary")
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# Make sure read preference is respected after a `.skip(...)`.
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bars = Bar.objects.skip(1).read_preference(ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(bars._read_preference, ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(
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bars._cursor._Cursor__read_preference, ReadPreference.SECONDARY_PREFERRED
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)
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# read_preference after limit
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# Make sure read preference is respected after a `.limit(...)`.
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bars = Bar.objects.limit(1).read_preference(ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(bars._read_preference, ReadPreference.SECONDARY_PREFERRED)
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self.assertEqual(
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bars._cursor._Cursor__read_preference, ReadPreference.SECONDARY_PREFERRED
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)
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# read_preference after order_by
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# Make sure read preference is respected after an `.order_by(...)`.
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bars = Bar.objects.order_by("txt").read_preference(
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ReadPreference.SECONDARY_PREFERRED
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)
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@ -4637,7 +4670,7 @@ class QuerySetTest(unittest.TestCase):
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bars._cursor._Cursor__read_preference, ReadPreference.SECONDARY_PREFERRED
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)
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# read_preference after hint
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# Make sure read preference is respected after a `.hint(...)`.
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bars = Bar.objects.hint([("txt", 1)]).read_preference(
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ReadPreference.SECONDARY_PREFERRED
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)
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