[pull] main from django:main

AUTHORS

@@ -891,6 +891,7 @@ answer newbie questions, and generally made Django that much better:
     Ramon Saraiva <ramonsaraiva@gmail.com>
     Ram Rachum <ram@rachum.com>
     Randy Barlow <randy@electronsweatshop.com>
+    Raoni Timo <raoni@relume.io>
     Raphaël Barrois <raphael.barrois@m4x.org>
     Raphael Michel <mail@raphaelmichel.de>
     Raúl Cumplido <raulcumplido@gmail.com>

django/db/backends/postgresql/base.py

@@ -216,11 +216,15 @@ def pool(self):
             # Ensure we run in autocommit, Django properly sets it later on.
             connect_kwargs["autocommit"] = True
             enable_checks = self.settings_dict["CONN_HEALTH_CHECKS"]
+            # Copy to avoid mutating the user's settings dict.
+            pool_options = {**pool_options}
+            pool_options.setdefault(
+                "check", ConnectionPool.check_connection if enable_checks else None
+            )
             pool = ConnectionPool(
                 kwargs=connect_kwargs,
                 open=False,  # Do not open the pool during startup.
                 configure=self._configure_connection,
-                check=ConnectionPool.check_connection if enable_checks else None,
                 **pool_options,
             )
             # setdefault() ensures that multiple threads don't set this in

tests/backends/postgresql/tests.py

@@ -325,6 +325,33 @@ def test_pooling_health_checks(self):
         finally:
             new_connection.close_pool()
 
+    @unittest.skipUnless(is_psycopg3, "psycopg3 specific test")
+    def test_pool_check_can_be_overridden(self):
+        def custom_check(conn):
+            pass
+
+        new_connection = no_pool_connection(alias="default_pool")
+        new_connection.settings_dict["OPTIONS"]["pool"] = {"check": custom_check}
+
+        for enable_checks in (True, False):
+            with self.subTest(CONN_HEALTH_CHECKS=enable_checks):
+                new_connection.settings_dict["CONN_HEALTH_CHECKS"] = enable_checks
+                try:
+                    self.assertIs(new_connection.pool._check, custom_check)
+                finally:
+                    new_connection.close_pool()
+
+    @unittest.skipUnless(is_psycopg3, "psycopg3 specific test")
+    def test_pool_options_not_mutated(self):
+        pool_options = {"min_size": 0, "max_size": 2}
+        new_connection = no_pool_connection(alias="default_pool")
+        new_connection.settings_dict["OPTIONS"]["pool"] = pool_options
+        try:
+            self.assertIsNotNone(new_connection.pool)
+        finally:
+            new_connection.close_pool()
+        self.assertEqual(pool_options, {"min_size": 0, "max_size": 2})
+
     @unittest.skipUnless(is_psycopg3, "psycopg3 specific test")
     def test_cannot_open_new_connection_in_atomic_block(self):
         new_connection = no_pool_connection(alias="default_pool")