Fixed #29738 -- Allowed serializing psycopg2 range types in migrations.

2 files changed, 20 insertions, 0 deletions

diff --git a/django/contrib/postgres/apps.py b/django/contrib/postgres/apps.py
index 9f29d72f49..97475de6f7 100644
--- a/django/contrib/postgres/apps.py
+++ b/django/contrib/postgres/apps.py
@@ -1,13 +1,21 @@
+from psycopg2.extras import (
+    DateRange, DateTimeRange, DateTimeTZRange, NumericRange,
+)
+
 from django.apps import AppConfig
 from django.db import connections
 from django.db.backends.signals import connection_created
+from django.db.migrations.writer import MigrationWriter
 from django.db.models import CharField, TextField
 from django.test.signals import setting_changed
 from django.utils.translation import gettext_lazy as _
 
 from .lookups import SearchLookup, TrigramSimilar, Unaccent
+from .serializers import RangeSerializer
 from .signals import register_type_handlers
 
+RANGE_TYPES = (DateRange, DateTimeRange, DateTimeTZRange, NumericRange)
+
 
 def uninstall_if_needed(setting, value, enter, **kwargs):
     """
@@ -26,6 +34,7 @@ def uninstall_if_needed(setting, value, enter, **kwargs):
         # and ready() connects it again to prevent unnecessary processing on
         # each setting change.
         setting_changed.disconnect(uninstall_if_needed)
+        MigrationWriter.unregister_serializer(RANGE_TYPES)
 
 
 class PostgresConfig(AppConfig):
@@ -54,3 +63,4 @@ class PostgresConfig(AppConfig):
         TextField.register_lookup(SearchLookup)
         CharField.register_lookup(TrigramSimilar)
         TextField.register_lookup(TrigramSimilar)
+        MigrationWriter.register_serializer(RANGE_TYPES, RangeSerializer)
diff --git a/django/contrib/postgres/serializers.py b/django/contrib/postgres/serializers.py
new file mode 100644
index 0000000000..1b1c2f1112
--- /dev/null
+++ b/django/contrib/postgres/serializers.py
@@ -0,0 +1,10 @@
+from django.db.migrations.serializer import BaseSerializer
+
+
+class RangeSerializer(BaseSerializer):
+    def serialize(self):
+        module = self.value.__class__.__module__
+        # Ranges are implemented in psycopg2._range but the public import
+        # location is psycopg2.extras.
+        module = 'psycopg2.extras' if module == 'psycopg2._range' else module
+        return '%s.%r' % (module, self.value), {'import %s' % module}