[2.2.x] Fixed #30332 -- Fixed crash of ordering by expressions with params in ArrayAgg and StringAgg.

Backport of d0315584b5 from master.

django/contrib/postgres/aggregates/mixins.py

@@ -21,13 +21,17 @@ class OrderableAggMixin:
 
     def as_sql(self, compiler, connection):
         if self.ordering:
-            self.extra['ordering'] = 'ORDER BY ' + ', '.join((
+            ordering_params = []
-                ordering_element.as_sql(compiler, connection)[0]
+            ordering_expr_sql = []
-                for ordering_element in self.ordering
+            for expr in self.ordering:
+                expr_sql, expr_params = expr.as_sql(compiler, connection)
+                ordering_expr_sql.append(expr_sql)
+                ordering_params.extend(expr_params)
+            sql, sql_params = super().as_sql(compiler, connection, ordering=(
+                'ORDER BY ' + ', '.join(ordering_expr_sql)
             ))
-        else:
+            return sql, sql_params + ordering_params
-            self.extra['ordering'] = ''
+        return super().as_sql(compiler, connection, ordering='')
-        return super().as_sql(compiler, connection)
 
     def get_source_expressions(self):
         return self.source_expressions + self.ordering

docs/releases/2.2.1.txt

@@ -17,3 +17,8 @@ Bugfixes
 
 * Fixed a regression in Django 2.2 that caused a crash when loading the
   template for the technical 500 debug page (:ticket:`30324`).
+
+* Fixed crash of ``ordering`` argument in
+  :class:`~django.contrib.postgres.aggregates.ArrayAgg` and
+  :class:`~django.contrib.postgres.aggregates.StringAgg` when it contains an
+  expression with params (:ticket:`30332`).

tests/postgres_tests/test_aggregates.py

@@ -1,6 +1,7 @@
 import json
 
 from django.db.models.expressions import F, Value
+from django.db.models.functions import Concat, Substr
 from django.test.testcases import skipUnlessDBFeature
 from django.test.utils import Approximate
 
@@ -38,6 +39,12 @@ class TestGeneralAggregate(PostgreSQLTestCase):
             ((F('boolean_field'), F('char_field').desc()), ['Foo4', 'Foo2', 'Foo3', 'Foo1']),
             ('char_field', ['Foo1', 'Foo2', 'Foo3', 'Foo4']),
             ('-char_field', ['Foo4', 'Foo3', 'Foo2', 'Foo1']),
+            (Concat('char_field', Value('@')), ['Foo1', 'Foo2', 'Foo3', 'Foo4']),
+            (Concat('char_field', Value('@')).desc(), ['Foo4', 'Foo3', 'Foo2', 'Foo1']),
+            (
+                (Substr('char_field', 1, 1), F('integer_field'), Substr('char_field', 4, 1).desc()),
+                ['Foo3', 'Foo1', 'Foo2', 'Foo4'],
+            ),
         )
         for ordering, expected_output in ordering_test_cases:
             with self.subTest(ordering=ordering, expected_output=expected_output):
@@ -165,6 +172,8 @@ class TestGeneralAggregate(PostgreSQLTestCase):
             (F('char_field').desc(), 'Foo4;Foo3;Foo2;Foo1'),
             (F('char_field').asc(), 'Foo1;Foo2;Foo3;Foo4'),
             (F('char_field'), 'Foo1;Foo2;Foo3;Foo4'),
+            (Concat('char_field', Value('@')), 'Foo1;Foo2;Foo3;Foo4'),
+            (Concat('char_field', Value('@')).desc(), 'Foo4;Foo3;Foo2;Foo1'),
         )
         for ordering, expected_output in ordering_test_cases:
             with self.subTest(ordering=ordering, expected_output=expected_output):