Fixed #16055 -- Fixed crash when filtering against char/text GenericRelation relation on PostgreSQL.

1 files changed, 31 insertions, 1 deletions

diff --git a/tests/backends/postgresql/test_operations.py b/tests/backends/postgresql/test_operations.py
index c2f2417923..632928ff87 100644
--- a/tests/backends/postgresql/test_operations.py
+++ b/tests/backends/postgresql/test_operations.py
@@ -2,9 +2,11 @@ import unittest
 
 from django.core.management.color import no_style
 from django.db import connection
+from django.db.models.expressions import Col
+from django.db.models.functions import Cast
 from django.test import SimpleTestCase
 
-from ..models import Person, Tag
+from ..models import Author, Book, Person, Tag
 
 
 @unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL tests.")
@@ -48,3 +50,31 @@ class PostgreSQLOperationsTests(SimpleTestCase):
             ),
             ['TRUNCATE "backends_person", "backends_tag" RESTART IDENTITY CASCADE;'],
         )
+
+    def test_prepare_join_on_clause_same_type(self):
+        author_table = Author._meta.db_table
+        author_id_field = Author._meta.get_field("id")
+        lhs_expr, rhs_expr = connection.ops.prepare_join_on_clause(
+            author_table,
+            author_id_field,
+            author_table,
+            author_id_field,
+        )
+        self.assertEqual(lhs_expr, Col(author_table, author_id_field))
+        self.assertEqual(rhs_expr, Col(author_table, author_id_field))
+
+    def test_prepare_join_on_clause_different_types(self):
+        author_table = Author._meta.db_table
+        author_id_field = Author._meta.get_field("id")
+        book_table = Book._meta.db_table
+        book_fk_field = Book._meta.get_field("author")
+        lhs_expr, rhs_expr = connection.ops.prepare_join_on_clause(
+            author_table,
+            author_id_field,
+            book_table,
+            book_fk_field,
+        )
+        self.assertEqual(lhs_expr, Col(author_table, author_id_field))
+        self.assertEqual(
+            rhs_expr, Cast(Col(book_table, book_fk_field), author_id_field)
+        )