[5.2.x] Fixed #35677 -- Avoided non-sticky filtering of prefetched many-to-many.

The original queryset._next_is_sticky() call never had the intended effect as
no further filtering was applied internally after the pk__in lookup making it
a noop.

In order to be coherent with how related filters are applied when retrieving
objects from a related manager the effects of what calling _next_is_sticky()
prior to applying annotations and filters to the queryset provided for
prefetching are emulated by allowing the reuse of all pre-existing JOINs.

Thanks David Glenck and Thiago Bellini Ribeiro for the detailed reports and
tests.

Backport of 2598b371a93e21d84b7a2a99b2329535c8c0c138 from main.

2 files changed, 11 insertions, 4 deletions

diff --git a/django/db/models/fields/related_descriptors.py b/django/db/models/fields/related_descriptors.py
index d858144152..7dcec5368b 100644
--- a/django/db/models/fields/related_descriptors.py
+++ b/django/db/models/fields/related_descriptors.py
@@ -114,7 +114,10 @@ def _filter_prefetch_queryset(queryset, field_name, instances):
         if high_mark is not None:
             predicate &= LessThanOrEqual(window, high_mark)
         queryset.query.clear_limits()
-    return queryset.filter(predicate)
+    # All pre-existing JOINs must be re-used when applying the predicate to
+    # avoid unintended spanning of multi-valued relationships.
+    queryset.query.add_q(predicate, reuse_all=True)
+    return queryset
 
 
 class ForwardManyToOneDescriptor:
@@ -1164,7 +1167,7 @@ def create_forward_many_to_many_manager(superclass, rel, reverse):
             queryset._add_hints(instance=instances[0])
             queryset = queryset.using(queryset._db or self._db)
             queryset = _filter_prefetch_queryset(
-                queryset._next_is_sticky(), self.query_field_name, instances
+                queryset, self.query_field_name, instances
             )
 
             # M2M: need to annotate the query in order to get the primary model
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index ddf6c891fa..ec47d9aa24 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -1616,7 +1616,7 @@ class Query(BaseExpression):
     def add_filter(self, filter_lhs, filter_rhs):
         self.add_q(Q((filter_lhs, filter_rhs)))
 
-    def add_q(self, q_object):
+    def add_q(self, q_object, reuse_all=False):
         """
         A preprocessor for the internal _add_q(). Responsible for doing final
         join promotion.
@@ -1630,7 +1630,11 @@ class Query(BaseExpression):
         existing_inner = {
             a for a in self.alias_map if self.alias_map[a].join_type == INNER
         }
-        clause, _ = self._add_q(q_object, self.used_aliases)
+        if reuse_all:
+            can_reuse = set(self.alias_map)
+        else:
+            can_reuse = self.used_aliases
+        clause, _ = self._add_q(q_object, can_reuse)
         if clause:
             self.where.add(clause, AND)
         self.demote_joins(existing_inner)