Test client fails after 10398

[Ville Säävuori]

After changeset r10398 my tests started failing for an app that uses signals. (post_save signal in this case -- nothing special in there)

Traceback from the test client:

Traceback (most recent call last):
  File "/home/syneusfi/new_intra/pylib/heimlich/tests.py", line 142, in test_ticket_creation
    response = self.client.post('/partiovaruste/bugilista/uusi/', postdata)
  File "/home/syneusfi/django/django/test/client.py", line 306, in post
    response = self.request(**r)
  File "/home/syneusfi/django/django/test/client.py", line 224, in request
    response = self.handler(environ)
  File "/home/syneusfi/django/django/test/client.py", line 75, in __call__
    signals.request_finished.disconnect(close_connection)
  File "/home/syneusfi/django/django/dispatch/dispatcher.py", line 124, in disconnect
    (r_key, _) = self.receivers[index]
IndexError: list index out of range

The tests in question pass for revision r10397. I tested that they also pass when reverting only django/django/dispatch/dispatcher.py to the previous revision, so I'm quite confident that r10398 broke something here.

[Russell Keith-Magee]

Any chance you could give us an example of a test that is actually failing? It's great to know that you have a test that is failing, but unless you can give us the actual test, it is a lot more difficult to diagnose what is going on here.

[Karataev Pavel]

see ​http://code.djangoproject.com/changeset/10398 dispatcher.py

example:

In [1]: l = [1,2,3]
In [2]: for i in xrange(len(l)):

...: del l[i]

---

IndexError Traceback (most recent call last)

IndexError: list assignment index out of range

[Karataev Pavel]

see attachment

[Russell Keith-Magee]

1. This isn't fixed until the patch is applied to trunk.
2. The patch doesn't contain a test case.
3. The test case you have provided in the comments is pure python - it doesn't contain any Django code. The example breaks for a very good reason - after deleting two items from the list, there isn't an l[2] to delete. This is purely normal python behaviour.

[Ville Säävuori]

Replying to russellm:

Any chance you could give us an example of a test that is actually failing?

I wrote a small test project + testapp to demonstrate this but I couldn't reproduce the bug in there. I'll try to strip out the problematic app+test from the original project next.

Weird thing is, this was the only test that broke in dozens of projects with lots of tests. But I'm still quite sure it's a bug in Django.

[Karataev Pavel]

This issue occurs when there are more than one listener and the last one is disconnected.

test case with django:

s = Signal()
r1 = lambda kw: None
r2 = lambda kw: None
s.connect(r1)
s.connect(r2)
s.disconnect(r1)

Traceback (most recent call last):

File "<console>", line 1, in <module>
File "/home/minmax/projects/lib/django/dispatch/dispatcher.py", line 124, in disconnect

(r_key, _) = self.receivers[index]

IndexError: list index out of range

[Karataev Pavel]

sorry

>>> s = Signal()
>>> r1 = lambda **kw: None
>>> r2 = lambda **kw: None
>>> s.connect(r1)
>>> s.connect(r2)
>>> s.disconnect(r1)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/minmax/projects/lib/django/dispatch/dispatcher.py", line 124, in disconnect
    (r_key, _) = self.receivers[index]
IndexError: list index out of range

[Adrian Holovaty]

I'm getting this error as well, after [10398]. Thanks for the patch -- I'm going to take a look.

[Adrian Holovaty]

(In [10497]) Fixed #10753 -- Fixed regression in dispatcher after [10398]. Thanks for the patch and tests, minmax

[Jacob]

(In [10503]) [1.0.X] Fixed #10753 -- Fixed regression in dispatcher after [10398]. Thanks for the patch and tests, minmax. Backport of r10497 from trunk.

[Jacob]

Milestone 1.1 deleted