From 717ee63e5615a6c3a018351a07028513f9b01f0b Mon Sep 17 00:00:00 2001
From: Tim Graham <timograham@gmail.com>
Date: Thu, 25 Oct 2018 19:54:48 -0400
Subject: [PATCH] Refs #27025 -- Removed obsolete sqlite3 transaction
 management workaround for Python 3.6+.

Obsolete per https://bugs.python.org/issue10740#msg274816.
---
 django/db/backends/base/base.py        | 11 +----------
 django/db/backends/sqlite3/features.py |  4 +++-
 django/db/transaction.py               |  4 ++--
 3 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/django/db/backends/base/base.py b/django/db/backends/base/base.py
index c8c18f5b19..f97d171c96 100644
--- a/django/db/backends/base/base.py
+++ b/django/db/backends/base/base.py
@@ -395,7 +395,7 @@ class BaseDatabaseWrapper:
 
         start_transaction_under_autocommit = (
             force_begin_transaction_with_broken_autocommit and not autocommit and
-            self.features.autocommits_when_autocommit_is_off
+            hasattr(self, '_start_transaction_under_autocommit')
         )
 
         if start_transaction_under_autocommit:
@@ -595,15 +595,6 @@ class BaseDatabaseWrapper:
             allow_thread_sharing=False,
         )
 
-    def _start_transaction_under_autocommit(self):
-        """
-        Only required when autocommits_when_autocommit_is_off = True.
-        """
-        raise NotImplementedError(
-            'subclasses of BaseDatabaseWrapper may require a '
-            '_start_transaction_under_autocommit() method'
-        )
-
     def schema_editor(self, *args, **kwargs):
         """
         Return a new instance of this backend's SchemaEditor.
diff --git a/django/db/backends/sqlite3/features.py b/django/db/backends/sqlite3/features.py
index c56a393772..efb9413119 100644
--- a/django/db/backends/sqlite3/features.py
+++ b/django/db/backends/sqlite3/features.py
@@ -1,3 +1,5 @@
+import sys
+
 from django.db import utils
 from django.db.backends.base.features import BaseDatabaseFeatures
 from django.utils.functional import cached_property
@@ -13,7 +15,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_timezones = False
     max_query_params = 999
     supports_mixed_date_datetime_comparisons = False
-    autocommits_when_autocommit_is_off = True
+    autocommits_when_autocommit_is_off = sys.version_info < (3, 6)
     can_introspect_decimal_field = False
     can_introspect_duration_field = False
     can_introspect_positive_integer_field = True
diff --git a/django/db/transaction.py b/django/db/transaction.py
index 39c3402925..901d8b62e7 100644
--- a/django/db/transaction.py
+++ b/django/db/transaction.py
@@ -173,8 +173,8 @@ class Atomic(ContextDecorator):
             connection.commit_on_exit = True
             connection.needs_rollback = False
             if not connection.get_autocommit():
-                # Some database adapters (namely sqlite3) don't handle
-                # transactions and savepoints properly when autocommit is off.
+                # sqlite3 in Python < 3.6 doesn't handle transactions and
+                # savepoints properly when autocommit is off.
                 # Turning autocommit back on isn't an option; it would trigger
                 # a premature commit. Give up if that happens.
                 if connection.features.autocommits_when_autocommit_is_off: