get_db_prep_lookup logic about django-taggit HOT 18 CLOSED

Hrm, can you give an example with a traceback that triggers this?

from django-taggit.

Yeah np. My object has a tags field (well manager) on it. I can save a new instance with or without tags. No problem as this never hits get_db_prep_lookup. But if I try to even just save again with no modifications (or with) to the tags field, it throws the exception.
Traceback:
File "/Library/Python/2.6/site-packages/django/core/handlers/base.py" in get_response
92. response = callback(request, _callback_args, *_callback_kwargs)
File "/Library/Python/2.6/site-packages/django/contrib/admin/sites.py" in root
490. return self.model_page(request, _url.split('/', 2))
File "/Library/Python/2.6/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
44. response = view_func(request, *args, *_kwargs)
File "/Library/Python/2.6/site-packages/django/contrib/admin/sites.py" in model_page
509. return admin_obj(request, rest_of_url)
File "/Library/Python/2.6/site-packages/django/contrib/admin/options.py" in call
1098. return self.change_view(request, unquote(url))
File "/Library/Python/2.6/site-packages/django/db/transaction.py" in _commit_on_success
240. res = func(_args, *_kw)
File "/Library/Python/2.6/site-packages/django/contrib/admin/options.py" in change_view
831. form.save_m2m()
File "/Library/Python/2.6/site-packages/django/forms/models.py" in save_m2m
75. f.save_form_data(instance, cleaned_data[f.name])
File "/Library/Python/2.6/site-packages/taggit/managers.py" in save_form_data
48. getattr(instance, self.name).set(_value)
File "/Library/Python/2.6/site-packages/taggit/utils.py" in inner
11. return func(self, *args, *_kwargs)
File "/Library/Python/2.6/site-packages/taggit/managers.py" in set
121. self.clear()
File "/Library/Python/2.6/site-packages/taggit/utils.py" in inner
11. return func(self, _args, *_kwargs)
File "/Library/Python/2.6/site-packages/taggit/managers.py" in clear
133. content_type=ContentType.objects.get_for_model(self.model)).delete()
File "/Library/Python/2.6/site-packages/django/db/models/query.py" in delete
399. delete_objects(seen_objs)
File "/Library/Python/2.6/site-packages/django/db/models/query.py" in delete_objects
1037. del_query.delete_batch_related(pk_list)
File "/Library/Python/2.6/site-packages/django/db/models/sql/subqueries.py" in delete_batch_related
56. AND)
File "/Library/Python/2.6/site-packages/django/db/models/sql/where.py" in add
56. obj, params = obj.process(lookup_type, value)
File "/Library/Python/2.6/site-packages/django/db/models/sql/where.py" in process
269. params = self.field.get_db_prep_lookup(lookup_type, value)
File "/Library/Python/2.6/site-packages/taggit/managers.py" in get_db_prep_lookup
65. raise ValueError("You can't combine Tag objects and strings, pick one !")

Exception Type: ValueError at /admin/articles/article/1061/
Exception Value: You can't combine Tag objects and strings, pick one!

from django-taggit.

I just pushed a test that seems to test the same behavior you described, can you fork and try to add a test case that shows the issue?

from django-taggit.

======================================================================
ERROR: test_add_tag (taggit.tests.tests.AddTagTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Python/2.6/site-packages/taggit/tests/tests.py", line 34, in test_add_tag
    apple.tags.remove('green')
  File "/Library/Python/2.6/site-packages/taggit/utils.py", line 11, in inner
    return func(self, *args, **kwargs)
  File "/Library/Python/2.6/site-packages/taggit/managers.py", line 128, in remove
    tag__name__in=tags).delete()
  File "/Library/Python/2.6/site-packages/django/db/models/query.py", line 399, in delete
    delete_objects(seen_objs)
  File "/Library/Python/2.6/site-packages/django/db/models/query.py", line 1037, in delete_objects
    del_query.delete_batch_related(pk_list)
  File "/Library/Python/2.6/site-packages/django/db/models/sql/subqueries.py", line 56, in delete_batch_related
    AND)
  File "/Library/Python/2.6/site-packages/django/db/models/sql/where.py", line 56, in add
    obj, params = obj.process(lookup_type, value)
  File "/Library/Python/2.6/site-packages/django/db/models/sql/where.py", line 269, in process
    params = self.field.get_db_prep_lookup(lookup_type, value)
  File "/Library/Python/2.6/site-packages/taggit/managers.py", line 65, in get_db_prep_lookup
    raise ValueError("You can't combine Tag objects and strings, pick one!")
ValueError: You can't combine Tag objects and strings, pick one!

======================================================================
ERROR: test_form (taggit.tests.tests.TaggableFormTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Python/2.6/site-packages/taggit/tests/tests.py", line 74, in test_form
    f.save()
  File "/Library/Python/2.6/site-packages/django/forms/models.py", line 407, in save
    fail_message, commit, exclude=self._meta.exclude)
  File "/Library/Python/2.6/site-packages/django/forms/models.py", line 79, in save_instance
    save_m2m()
  File "/Library/Python/2.6/site-packages/django/forms/models.py", line 75, in save_m2m
    f.save_form_data(instance, cleaned_data[f.name])
  File "/Library/Python/2.6/site-packages/taggit/managers.py", line 48, in save_form_data
    getattr(instance, self.name).set(*value)
  File "/Library/Python/2.6/site-packages/taggit/utils.py", line 11, in inner
    return func(self, *args, **kwargs)
  File "/Library/Python/2.6/site-packages/taggit/managers.py", line 121, in set
    self.clear()
  File "/Library/Python/2.6/site-packages/taggit/utils.py", line 11, in inner
    return func(self, *args, **kwargs)
  File "/Library/Python/2.6/site-packages/taggit/managers.py", line 133, in clear
    content_type=ContentType.objects.get_for_model(self.model)).delete()
  File "/Library/Python/2.6/site-packages/django/db/models/query.py", line 399, in delete
    delete_objects(seen_objs)
  File "/Library/Python/2.6/site-packages/django/db/models/query.py", line 1037, in delete_objects
    del_query.delete_batch_related(pk_list)
  File "/Library/Python/2.6/site-packages/django/db/models/sql/subqueries.py", line 56, in delete_batch_related
    AND)
  File "/Library/Python/2.6/site-packages/django/db/models/sql/where.py", line 56, in add
    obj, params = obj.process(lookup_type, value)
  File "/Library/Python/2.6/site-packages/django/db/models/sql/where.py", line 269, in process
    params = self.field.get_db_prep_lookup(lookup_type, value)
  File "/Library/Python/2.6/site-packages/taggit/managers.py", line 65, in get_db_prep_lookup
    raise ValueError("You can't combine Tag objects and strings, pick one!")
ValueError: You can't combine Tag objects and strings, pick one!

======================================================================
FAIL: test_lookup_by_tag (taggit.tests.tests.LookupByTagTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Python/2.6/site-packages/taggit/tests/tests.py", line 58, in test_lookup_by_tag
    self.assertEqual(list(Food.objects.filter(tags="red").distinct()), [apple])
AssertionError: [] != [<Food: apple>]

----------------------------------------------------------------------
Ran 3 tests in 29.757s

FAILED (failures=1, errors=2)
Destroying test database...

from django-taggit.

So the current tests fail for you? What version of django are you using?

from django-taggit.

1.1.1 - unmodified

just throwing taggit.tests into my installed apps and running 'manage.py test taggit'. tried it on a couple boxes with the same result

osx10.6 with python 2.6
debian lenny with python 2.5

from django-taggit.

bec0cf1 added some more debug information. Can you rerun the tests and provide the output again, I'm unable to reproduce the test failures you're getting unfortunately.

from django-taggit.

Ok. It has to be something on my end. I think its grappelli - but not sure how. I can build a new project with a simple app in virtualenv and taggit works perfectly and all tests pass. I then stripped everything I could out of my real project. The only things in there is one of my apps (pretty generic app) and grappelli. im gonna keep testing. sorry for wasting your time. it seems maybe grapelli is mangling the input or something

from django-taggit.

If you can figure out what grapelli is sending let me know and I'll see if I can work around that. I thought grapelli was just a new "theme" for the admin, but perhaps it's doing more than that.

from django-taggit.

It's wildly broken on MySQL.

http://github.com/bfirsh/django-taggit/commit/f174d93784235269ce9249d25fed037fd0c262f6

That gets some of the way, but there are still subquery issues.

from django-taggit.

I've applied the long patch. Let me know what other issues you're seeing (if you can file a seperate ticket that'd be great, I'm going to consider this one a grapelli issue for now).

from django-taggit.

Ok. Its not grappelli. I did a new clean app with grappelli and it worked fine. im also using the same 'articles' app I have with it and it seems to be working without issue (although not on my production app). There is something else. I'll keep looking.

After pulling the 'long' patch I'm getting a different error. I was actually getting this one before when I was hacking around with get_db_prep_lookup, but assumed I was just breaking something else.

(1093, "You can't specify target table 'taggit_taggeditem' for update in FROM clause")

from django-taggit.

Also, on a side note. All the places I'm having issues I'm running MySQL. The places where its working is SQLite3. Only reason I mention this is because of bfirsh's comment "It's wildly broken on MySQL."

from django-taggit.

Are you running on MySQL? If so then I've got something to start looking at.

from django-taggit.

Hehe, ok so it's a MySQL issue. I'm guessing the UPDATE query under mysql doesn't like the subselect. Fixing this may be tough.

from django-taggit.

Yep, that's the issue I had with MySQL. Sorry not to be much help, but I gave up and just used a simple many to many tagging system in the end.

from django-taggit.

ouch. this was the last little bit before launch (on the 1st). i may just have to gut the taggit out of it and go to manytomany if i cant fix today. im not gonna give up just yet though. im gonna see if i can't get it going.

from django-taggit.

Ok everything is working now except for queries like Food.objects.filter(tags="red"). Instead you need to do Food.objects.filter(tags__in=["red"]). I'm trying to figure out the solution inside of django-taggit, but for now everything else seems to be working. Thanks for the report (I'm closing this ticket and opening a new one for the specific issue).

from django-taggit.