excluded column not removed from sequence

[mbertheau]

With this code:

class ParticipantTable(Table):
    email = Column(verbose_name=_("Email"), accessor='user.email')
    register_datetime = Column(verbose_name=_("Register date"))

    class Meta(DashboardTable.Meta):
        model = Participant
        fields = ()
        sequence = ('email', 'register_datetime')


class ParticipantCancelTable(ParticipantTable):
    status = TemplateColumn(verbose_name=_("Status"),
                            template_name='dashboard/catalogue/participant_row_status.html',
                            order_by='status')

    class Meta(ParticipantTable.Meta):
        pass


class TrainerParticipantTable(ParticipantCancelTable):
    class Meta(ParticipantCancelTable.Meta):
        exclude = ('register_datetime', 'order', 'actions')

I get

  File "/home/markus/src/machtfit/apps/dashboard/catalogue/tables.py", line 94, in <module>
    class TrainerParticipantTable(ParticipantCancelTable):
  File "/home/markus/src/django-tables2/django_tables2/tables.py", line 203, in __new__
    attrs["base_columns"] = SortedDict(((x, attrs["base_columns"][x]) for x in opts.sequence))
  File "/home/markus/src/django/django/utils/datastructures.py", line 135, in __init__
    for key, value in data:
  File "/home/markus/src/django-tables2/django_tables2/tables.py", line 203, in <genexpr>
    attrs["base_columns"] = SortedDict(((x, attrs["base_columns"][x]) for x in opts.sequence))
KeyError: u'register_datetime'

The reason is that while ParticipantTable.sequence is enforced by reordering base_columns, a potential exclusion is not taken into account.

A workaround is to specify sequence on TrainerParticipantTable and leave 'register_datetime` out.

[onnokort]

Upvote! Fell into the exactly same trap with django_tables2 version 1.0.4.

[jieter]

Finally started looking at this. I reduced the example to this:

    class PersonTable(tables.Table):
        class Meta:
            model = Person
            fields = ()
            sequence = ('first_name', 'last_name', 'occupation')

    class AnotherPersonTable(PersonTable):
        class Meta(PersonTable.Meta):
            exclude = ('first_name', 'last_name')

Resulting in the error in django_tables2/tables.py:222:

>   base_columns = OrderedDict(((x, base_columns[x]) for x in opts.sequence))
E   KeyError: u'first_name'

[jieter]

@mbertheau Thanks for reporting the issue, sorry it took so long to fix. Next time it will really help to have a simple, compact reproducible test case.

[jieter]

It seems this is not fixed at all, because instantiating the AnotherPersonTable raises a KeyError. This is a more complete test case, which currently fails:

def test_exclude_should_work_on_sequence_too():
    '''
    It should be possible to define a sequence on a table
    and exclude it in a child of that table.
    '''
    class PersonTable(tables.Table):
        first_name = tables.Column()
        last_name = tables.Column()
        occupation = tables.Column()

        class Meta:
            model = Person
            sequence = ('first_name', 'last_name', 'occupation')

    class AnotherPersonTable(PersonTable):
        class Meta(PersonTable.Meta):
            exclude = ('first_name', 'last_name')

    tableA = PersonTable(Person.objects.all())
    assert tableA.columns.names() == ['first_name', 'last_name', 'occupation']

    tableB = AnotherPersonTable(Person.objects.all())
    assert tableB.columns.names() == ['occupation']