get_constraints broke on newer version of sqlite.

[dmrsearch]

Running the test suite with the latest version of sqlite "3.8.9" gives the following error. The way sqlite brings back constraints change between the two versions.

ERROR: test_unique_together_meta (inspectdb.tests.InspectDBTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/sthompso/PycharmProjects/django/tests/inspectdb/tests.py", line 225, in test_unique_together_meta
    stdout=out)
  File "/Users/sthompso/PycharmProjects/django/django/core/management/__init__.py", line 118, in call_command
    return command.execute(*args, **defaults)
  File "/Users/sthompso/PycharmProjects/django/django/core/management/base.py", line 398, in execute
    output = self.handle(*args, **options)
  File "/Users/sthompso/PycharmProjects/django/django/core/management/commands/inspectdb.py", line 25, in handle
    for line in self.handle_inspection(options):
  File "/Users/sthompso/PycharmProjects/django/django/core/management/commands/inspectdb.py", line 69, in handle_inspection
    constraints = connection.introspection.get_constraints(cursor, table_name)
  File "/Users/sthompso/PycharmProjects/django/django/db/backends/sqlite3/introspection.py", line 242, in get_constraints
    for number, index, unique in cursor.fetchall():
ValueError: too many values to unpack

[maestrofjp]

It appears that database.index_list() in sqlite3 has changed:

Current documentation for the latest release 3.8.9:
​http://www.sqlite.org/pragma.html#pragma_index_list

Older documentation (don't know which version exactly but shows what Django is relying on):
​https://www.safaribooksonline.com/library/view/using-sqlite/9781449394592/re183.html

[maestrofjp]

The new version of 3.8.9 returns 5 columns while we are relying that is only has 3 columns.

[maestrofjp]

The original reporter was on OSX as I helped him with this is at PyCon Sprints. I can confirm that upgrading from Sqlite3 3.8.2 to 3.8.9 on Ubuntu 14 causes the above issue. This issue is reproducible. Sqlite 3.8.9 was released on April 8, 2015. I had to install it from source on Ubuntu.

[maestrofjp]

I have a PR in progress that works for both behaviors.

[maestrofjp]

Patch is PR4494 on GH:

​https://github.com/django/django/pull/4494

[Tim Graham <timograham@…>]

In f8e8853:

Fixed #24637 -- Fixed database introspection with SQLite 3.8.9.

[Tim Graham <timograham@…>]

In d74903e4:

[1.7.x] Fixed #24637 -- Fixed database introspection with SQLite 3.8.9.

Backport of f8e8853b51476af1cc75a229dadc990c9ccf45ec from master

[Tim Graham <timograham@…>]

In 309142d:

[1.8.x] Fixed #24637 -- Fixed database introspection with SQLite 3.8.9.

Backport of f8e8853b51476af1cc75a229dadc990c9ccf45ec from master