Fixed #31956 -- Fixed crash of ordering by JSONField with a custom decoder on PostgreSQL.

Thanks Marc Debureaux for the report.
Thanks Simon Charette, Nick Pope, and Adam Johnson for reviews.

2 files changed, 4 insertions, 4 deletions

diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index ed911a91da..03c7a3c284 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -200,7 +200,10 @@ class DatabaseWrapper(BaseDatabaseWrapper):
             # Set the isolation level to the value from OPTIONS.
             if self.isolation_level != connection.isolation_level:
                 connection.set_session(isolation_level=self.isolation_level)
-
+        # Register dummy loads() to avoid a round trip from psycopg2's decode
+        # to json.dumps() to json.loads(), when using a custom decoder in
+        # JSONField.
+        psycopg2.extras.register_default_jsonb(conn_or_curs=connection, loads=lambda x: x)
         return connection
 
     def ensure_timezone(self):
diff --git a/django/db/backends/postgresql/operations.py b/django/db/backends/postgresql/operations.py
index a3442231af..1ce5755bf5 100644
--- a/django/db/backends/postgresql/operations.py
+++ b/django/db/backends/postgresql/operations.py
@@ -74,9 +74,6 @@ class DatabaseOperations(BaseDatabaseOperations):
     def time_trunc_sql(self, lookup_type, field_name):
         return "DATE_TRUNC('%s', %s)::time" % (lookup_type, field_name)
 
-    def json_cast_text_sql(self, field_name):
-        return '(%s)::text' % field_name
-
     def deferrable_sql(self):
         return " DEFERRABLE INITIALLY DEFERRED"