Fixed #20463 -- Made get_or_create more robust.

When an exception other than IntegrityError was raised, get_or_create
could fail and leave the database connection in an unusable state.

Thanks UloPe for the report.

django/db/models/query.py

@@ -9,7 +9,7 @@ import warnings
 
 from django.conf import settings
 from django.core import exceptions
-from django.db import connections, router, transaction, IntegrityError
+from django.db import connections, router, transaction, DatabaseError
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.fields import AutoField
 from django.db.models.query_utils import (Q, select_related_descend,
@@ -382,13 +382,13 @@ class QuerySet(object):
                 obj.save(force_insert=True, using=self.db)
                 transaction.savepoint_commit(sid, using=self.db)
                 return obj, True
-            except IntegrityError:
+            except DatabaseError:
                 transaction.savepoint_rollback(sid, using=self.db)
                 exc_info = sys.exc_info()
                 try:
                     return self.get(**lookup), False
                 except self.model.DoesNotExist:
-                    # Re-raise the IntegrityError with its original traceback.
+                    # Re-raise the DatabaseError with its original traceback.
                     six.reraise(*exc_info)
 
     def _earliest_or_latest(self, field_name=None, direction="-"):

tests/get_or_create/tests.py

@@ -2,14 +2,16 @@ from __future__ import absolute_import
 
 from datetime import date
 import traceback
+import warnings
 
-from django.db import IntegrityError
+from django.db import IntegrityError, DatabaseError
 from django.test import TestCase, TransactionTestCase
 
 from .models import Person, ManualPrimaryKeyTest, Profile, Tag, Thing
 
 
 class GetOrCreateTests(TestCase):
+
     def test_get_or_create(self):
         p = Person.objects.create(
             first_name='John', last_name='Lennon', birthday=date(1940, 10, 9)
@@ -64,6 +66,22 @@ class GetOrCreateTests(TestCase):
             formatted_traceback = traceback.format_exc()
             self.assertIn('obj.save', formatted_traceback)
 
+    def test_savepoint_rollback(self):
+        # Regression test for #20463: the database connection should still be
+        # usable after a DataError or ProgrammingError in .get_or_create().
+        try:
+            # Hide warnings when broken data is saved with a warning (MySQL).
+            with warnings.catch_warnings():
+                warnings.simplefilter('ignore')
+                Person.objects.get_or_create(
+                    birthday=date(1970, 1, 1),
+                    defaults={'first_name': "\xff", 'last_name': "\xff"})
+        except DatabaseError:
+            Person.objects.create(
+                first_name="Bob", last_name="Ross", birthday=date(1950, 1, 1))
+        else:
+            self.skipTest("This backend accepts broken utf-8.")
+
 
 class GetOrCreateTransactionTests(TransactionTestCase):