From 7d6916e82700896ef23c50720d8cf0de4d6b9074 Mon Sep 17 00:00:00 2001
From: matt ferrante <mferrante3@gmail.com>
Date: Mon, 6 Jan 2020 16:44:32 -0700
Subject: Fixed #29789 -- Added support for nested relations to
 FilteredRelation.

---
 django/db/models/sql/query.py | 39 +++++++++++++++++++++++++++++++--------
 1 file changed, 31 insertions(+), 8 deletions(-)

(limited to 'django/db/models/sql/query.py')

diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 1623263964..b53980a68f 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -1419,14 +1419,30 @@ class Query(BaseExpression):
     def add_filtered_relation(self, filtered_relation, alias):
         filtered_relation.alias = alias
         lookups = dict(get_children_from_q(filtered_relation.condition))
-        for lookup in chain((filtered_relation.relation_name,), lookups):
-            lookup_parts, field_parts, _ = self.solve_lookup_type(lookup)
+        relation_lookup_parts, relation_field_parts, _ = self.solve_lookup_type(filtered_relation.relation_name)
+        if relation_lookup_parts:
+            raise ValueError(
+                "FilteredRelation's relation_name cannot contain lookups "
+                "(got %r)." % filtered_relation.relation_name
+            )
+        for lookup in chain(lookups):
+            lookup_parts, lookup_field_parts, _ = self.solve_lookup_type(lookup)
             shift = 2 if not lookup_parts else 1
-            if len(field_parts) > (shift + len(lookup_parts)):
-                raise ValueError(
-                    "FilteredRelation's condition doesn't support nested "
-                    "relations (got %r)." % lookup
-                )
+            lookup_field_path = lookup_field_parts[:-shift]
+            for idx, lookup_field_part in enumerate(lookup_field_path):
+                if len(relation_field_parts) > idx:
+                    if relation_field_parts[idx] != lookup_field_part:
+                        raise ValueError(
+                            "FilteredRelation's condition doesn't support "
+                            "relations outside the %r (got %r)."
+                            % (filtered_relation.relation_name, lookup)
+                        )
+                else:
+                    raise ValueError(
+                        "FilteredRelation's condition doesn't support nested "
+                        "relations deeper than the relation_name (got %r for "
+                        "%r)." % (lookup, filtered_relation.relation_name)
+                    )
         self._filtered_relations[filtered_relation.alias] = filtered_relation
 
     def names_to_path(self, names, opts, allow_many=True, fail_on_missing=False):
@@ -1459,7 +1475,14 @@ class Query(BaseExpression):
                     field = self.annotation_select[name].output_field
                 elif name in self._filtered_relations and pos == 0:
                     filtered_relation = self._filtered_relations[name]
-                    field = opts.get_field(filtered_relation.relation_name)
+                    if LOOKUP_SEP in filtered_relation.relation_name:
+                        parts = filtered_relation.relation_name.split(LOOKUP_SEP)
+                        filtered_relation_path, field, _, _ = self.names_to_path(
+                            parts, opts, allow_many, fail_on_missing,
+                        )
+                        path.extend(filtered_relation_path[:-1])
+                    else:
+                        field = opts.get_field(filtered_relation.relation_name)
             if field is not None:
                 # Fields that contain one-to-many relations with a generic
                 # model (like a GenericForeignKey) cannot generate reverse
-- 
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