settings_changed signal uses strings for sender

[Alex Gaynor]

Since internally the sender is represented by the id() this is not valid, because there's no guarntee 2 strings of the same value have the same id(). This reproduces easily with PyPy:

alex@alex-gaynor-laptop:~/projects/django$ PYTHONPATH=`pwd` ~/projects/pypy/pypy-c tests/runtests.py --settings=test_sqlite settings_tests --failfast
Creating test database for alias 'default'...
Creating test database for alias 'other'...
...........F
======================================================================
FAIL: test_signal_callback_context_manager (regressiontests.settings_tests.tests.SettingsTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/alex/projects/django/tests/regressiontests/settings_tests/tests.py", line 80, in test_signal_callback_context_manager
    self.assertEqual(testvalue, 'override')
AssertionError: None != 'override'

----------------------------------------------------------------------
Ran 12 tests in 0.004s

FAILED (failures=1)
Destroying test database for alias 'default'...
Destroying test database for alias 'other'...

but it would also be possible to reproduce with CPython.

[Jannis Leidel]

In [16530]:

Fixed #16447 -- Stopped using the setting name as the sender parameter for the setting_changed signal. Thanks, Alex Gaynor.