[1.7.x] Fixed #23303 -- Added BEGIN and COMMIT statements to the output of sqlmigrate.

Backport of 5853c87a45 from master.

Conflicts:
	django/core/management/commands/sqlmigrate.py
	tests/user_commands/tests.py

django/core/management/commands/sqlmigrate.py

@@ -19,6 +19,14 @@ class Command(BaseCommand):
     )
 
     help = "Prints the SQL statements for the named migration."
+    output_transaction = True
+
+    def execute(self, *args, **options):
+        # sqlmigrate doesn't support coloring its output but we need to force
+        # no_color=True so that the BEGIN/COMMIT statements added by
+        # output_transaction don't get colored either.
+        options['no_color'] = True
+        return super(Command, self).execute(*args, **options)
 
     def handle(self, *args, **options):
 
@@ -50,5 +58,4 @@ class Command(BaseCommand):
         # for it
         plan = [(executor.loader.graph.nodes[targets[0]], options.get("backwards", False))]
         sql_statements = executor.collect_sql(plan)
-        for statement in sql_statements:
-            self.stdout.write(statement)
+        return '\n'.join(sql_statements)

docs/intro/tutorial01.txt

@@ -480,6 +480,7 @@ readability):
 
 .. code-block:: sql
 
+    BEGIN;
     CREATE TABLE polls_question (
         "id" serial NOT NULL PRIMARY KEY,
         "question_text" varchar(200) NOT NULL,
@@ -500,6 +501,7 @@ readability):
         FOREIGN KEY ("question_id")
         REFERENCES "polls_question" ("id")
         DEFERRABLE INITIALLY DEFERRED;
+    COMMIT;
 
 
 Note the following:

docs/ref/contrib/gis/tutorial.txt

@@ -285,6 +285,7 @@ This command should produce the following output:
 
 .. code-block:: sql
 
+    BEGIN;
     CREATE TABLE "world_worldborder" (
         "id" serial NOT NULL PRIMARY KEY,
         "name" varchar(50) NOT NULL,
@@ -302,6 +303,7 @@ This command should produce the following output:
     )
     ;
     CREATE INDEX "world_worldborder_mpoly_id" ON "world_worldborder" USING GIST ( "mpoly" );
+    COMMIT;
 
 .. note::
 

docs/ref/django-admin.txt

@@ -1127,6 +1127,8 @@ Prints the SQL for the named migration. This requires an active database
 connection, which it will use to resolve constraint names; this means you must
 generate the SQL against a copy of the database you wish to later apply it on.
 
+Note that ``sqlmigrate`` doesn't colorize its output.
+
 The :djadminopt:`--database` option can be used to specify the database for
 which to generate the SQL.
 

tests/migrations/test_commands.py

@@ -93,6 +93,13 @@ class MigrateTests(MigrationTestBase):
         """
         Makes sure that sqlmigrate does something.
         """
+        # Make sure the output is wrapped in a transaction
+        stdout = six.StringIO()
+        call_command("sqlmigrate", "migrations", "0001", stdout=stdout)
+        output = stdout.getvalue().lower()
+        self.assertIn("begin;", output)
+        self.assertIn("commit;", output)
+
         # Test forwards. All the databases agree on CREATE TABLE, at least.
         stdout = six.StringIO()
         call_command("sqlmigrate", "migrations", "0001", stdout=stdout)

tests/user_commands/management/commands/transaction.py

@@ -0,0 +1,10 @@
+from django.core.management.base import BaseCommand
+
+
+class Command(BaseCommand):
+    help = "Say hello."
+    args = ''
+    output_transaction = True
+
+    def handle(self, *args, **options):
+        return 'Hello!'

tests/user_commands/tests.py

@@ -74,6 +74,11 @@ class CommandTests(SimpleTestCase):
             if current_path is not None:
                 os.environ['PATH'] = current_path
 
+    def test_output_transaction(self):
+        out = StringIO()
+        management.call_command('transaction', stdout=out, no_color=True)
+        self.assertEqual(out.getvalue(), 'BEGIN;\nHello!\n\nCOMMIT;\n')
+
 
 class UtilsTests(SimpleTestCase):