QuerySet limit function now returns all docs in cursor when 0 is passed

docs/changelog.rst

@@ -4,6 +4,7 @@ Changelog
 
 Development
 ===========
+- QuerySet limit function behaviour: Passing 0 as parameter will return all the documents in the cursor #1611
 - (Fill this out as you fix issues and develop your features).
 
 Changes in 0.14.0

mongoengine/queryset/base.py

@@ -384,7 +384,7 @@ class BaseQuerySet(object):
             :meth:`skip` that has been applied to this cursor into account when
             getting the count
         """
-        if self._limit == 0 and with_limit_and_skip or self._none:
+        if self._limit == 0 and with_limit_and_skip is False or self._none:
             return 0
         return self._cursor.count(with_limit_and_skip=with_limit_and_skip)
 
@@ -759,10 +759,11 @@ class BaseQuerySet(object):
         """Limit the number of returned documents to `n`. This may also be
         achieved using array-slicing syntax (e.g. ``User.objects[:5]``).
 
-        :param n: the maximum number of objects to return
+        :param n: the maximum number of objects to return if n is greater than 0. 
+        When 0 is passed, returns all the documents in the cursor
         """
         queryset = self.clone()
-        queryset._limit = n if n != 0 else 1
+        queryset._limit = n
 
         # If a cursor object has already been created, apply the limit to it.
         if queryset._cursor_obj:

tests/queryset/queryset.py

@@ -124,6 +124,11 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual(len(people2), 1)
         self.assertEqual(people2[0], user_a)
 
+        # Test limit with 0 as parameter
+        people = self.Person.objects.limit(0)
+        self.assertEqual(people.count(with_limit_and_skip=True), 2)
+        self.assertEqual(len(people), 2)
+
         # Test chaining of only after limit
         person = self.Person.objects().limit(1).only('name').first()
         self.assertEqual(person, user_a)