[Django] #28789: Django won't update sqlite_master table using migrations.AlterModelTable, which causes loaddata to fail.

[Django]

#28789: Django won't update sqlite_master table using 
migrations.AlterModelTable,
which causes loaddata to fail.
-------------------------------------+-------------------------------------
               Reporter:  Rafael     |          Owner:  nobody
  Pires                              |
                   Type:  Bug        |         Status:  new
              Component:  Database   |        Version:  1.11
  layer (models, ORM)                |
               Severity:  Normal     |       Keywords:  migrations, sqlite3
           Triage Stage:             |      Has patch:  0
  Unreviewed                         |
    Needs documentation:  0          |    Needs tests:  0
Patch needs improvement:  0          |  Easy pickings:  0
                  UI/UX:  0          |
-------------------------------------+-------------------------------------
 I created a migration to rename a model table:


 {{{
 class Migration(migrations.Migration):

     dependencies = [
         ('assessment', '0105_previous_migration'),
     ]

     operations = [
         migrations.AlterModelTable(name='MyModel',
 table='myapp_newmymodel')
     ]

 }}}

 I can run this migration just fine, the table gets renamed and the project
 runs fine when I access it through my browser (with SQLite3 and MySQL).

 The problem is that: then I run "./manage.py test" the test fails to load
 the fixtures in the SQLite3 database:


 {{{
 ./manage.py test assessment.tests.test_models
 Creating test database for alias 'default'...
 System check identified no issues (0 silenced).
 E
 ======================================================================
 ERROR: setUpClass (assessment.tests.test_models.ModelsTestCase)
 ----------------------------------------------------------------------
 Traceback (most recent call last):
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/test/testcases.py", line 1036, in setUpClass
     'database': db_name,
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/core/management/__init__.py", line 131, in call_command
     return command.execute(*args, **defaults)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/core/management/base.py", line 330, in execute
     output = self.handle(*args, **options)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/core/management/commands/loaddata.py", line 69, in handle
     self.loaddata(fixture_labels)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/core/management/commands/loaddata.py", line 115, in
 loaddata
     connection.check_constraints(table_names=table_names)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/db/backends/sqlite3/base.py", line 286, in
 check_constraints
     column_name, referenced_column_name,
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/db/backends/utils.py", line 65, in execute
     return self.cursor.execute(sql, params)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/db/utils.py", line 94, in __exit__
     six.reraise(dj_exc_type, dj_exc_value, traceback)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/db/backends/utils.py", line 63, in execute
     return self.cursor.execute(sql)
   File "/home/user/virtualenv/myproject/local/lib/python2.7/site-
 packages/django/db/backends/sqlite3/base.py", line 326, in execute
     return Database.Cursor.execute(self, query)
 OperationalError: Problem installing fixtures: no such table:
 myapp_mymodel
 }}}

 *This table id is used by other tables as Foreign Key.*

 I looked into the code and it seems that the
 **migrations.AlterModelTable** is not updating the sqlite_master table, so
 other tables that references my new table with a Foreign Key are still
 pointing to myapp_mymodel instead of myapp_newmymodel. This happens during
 **check_constraints** execution, the sqlite3 backend gets the key columns
 using **get_key_columns** function, that reads the "CREATE TABLE" query in
 sqlite_master, but since the sqlite_master table wasn't updated correctly,
 the process fails.

 Just to be sure I ran "ALTER TABLE myapp_mymodel RENAME TO
 myapp_newmymodel" directly on the database and the sqlite_master table is
 updated correctly.

 Database: SQLite3
 Django version: 1.11.5

-- 
Ticket URL: <https://code.djangoproject.com/ticket/28789>
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