Upgrade notes

0.8.6

Now supports django 1.10. After upgrading, you may come across this error when running migrations:

Unhandled exception in thread started by <function wrapper at 0x7f32e681faa0>
Traceback (most recent call last):
  #...
  File "venv/lib/python2.7/site-packages/django/db/models/manager.py", line 120, in contribute_to_class
    setattr(model, name, ManagerDescriptor(self))
AttributeError: can't set attribute

To fix this, please replace ._default_manager in your historic migrations with .objects. For more detailed information see #469, #498

0.8.0

Dropped support for old Django versions and Python 2.6

Unsupported versions of django (1.4, 1.5, 1.6, 1.7) are no longer supported, and Python 2.6 is no longer supported.

These versions of python/django no longer receive security patches. You should upgrade to Python 2.7 and Django 1.8+.

Django 1.9 support has been added.

0.7.0

Dropped support for Django 1.5, Added support for 1.8

Django 1.5 support has been removed since django 1.5 is not supported upstream any longer.

Django 1.8 support has been added.

Deprecated: Calling recursetree/cache_tree_children with incorrectly-ordered querysets

Previously, when given a queryset argument, cache_tree_children called .order_by to ensure that the queryset was in the correct order. In 0.7, calling cache_tree_children with an incorrectly-ordered queryset will cause a deprecation warning. In 0.8, it will raise an error.

This also applies to recursetree, since it calls cache_tree_children.

This probably doesn’t affect many usages, since the default ordering for mptt models will work fine.

Minor: TreeManager.get_queryset no longer provided on Django < 1.6

Django renamed get_query_set to get_queryset in Django 1.6. For backward compatibility django-mptt had both methods available for 1.4-1.5 users.

This has been removed. You should use get_query_set on Django 1.4-1.5, and get_queryset if you’re on 1.6+.

Removed FeinCMSModelAdmin

Deprecated in 0.6.0, this has now been removed.

0.6.0

mptt now requires Python 2.6+, and supports Python 3.2+

mptt 0.6 drops support for both Python 2.4 and 2.5.

This was done to make it easier to support Python 3, as well as support the new context managers (delay_mptt_updates and disable_mptt_updates).

If you absolutely can’t upgrade your Python version, you’ll need to stick to mptt 0.5.5 until you can.

No more implicit empty_label=True on form fields

Until 0.5, TreeNodeChoiceField and TreeNodeMultipleChoiceField implicitly set empty_label=True. This was around since a long time ago, for unknown reasons. It has been removed in 0.6.0 as it caused occasional headaches for users.

If you were relying on this behavior, you’ll need to explicitly pass empty_label=True to any of those fields you use, otherwise you will start seeing new ‘——–’ choices appearing in them.

Deprecated FeinCMSModelAdmin

If you were using mptt.admin.FeinCMSModelAdmin, you should switch to using feincms.admin.tree_editor.TreeEditor instead, or you’ll get a loud deprecation warning.

0.4.2 to 0.5.5

TreeManager is now the default manager, YourModel.tree removed

In 0.5, TreeManager now behaves just like a normal django manager. If you don’t override anything, you’ll now get a TreeManager by default (.objects.)

Before 0.5, .tree was the default name for the TreeManager. That’s been removed, so we recommend updating your code to use .objects.

If you don’t want to update .tree to .objects everywhere just yet, you should add an explicit TreeManager to your models:

objects = tree = TreeManager()

save(raw=True) keyword argument removed

In earlier versions, MPTTModel.save() had a raw keyword argument. If True, the MPTT fields would not be updated during the save. This (undocumented) argument has now been removed.

_meta attributes moved to _mptt_meta

In 0.4, we deprecated all these attributes on model._meta. These have now been removed:

MyModel._meta.left_attr
MyModel._meta.right_attr
MyModel._meta.tree_id_attr
MyModel._meta.level_attr
MyModel._meta.tree_manager_attr
MyModel._meta.parent_attr
MyModel._meta.order_insertion_by

If you’re still using any of these, you’ll need to update by simply renaming _meta to _mptt_meta.

Running the tests

Tests are now run with:

cd tests/
./runtests.sh

The previous method (python setup.py test) no longer works since we switched to plain distutils.

0.3 to 0.4.2

Model changes

MPTT attributes on MyModel._meta deprecated, moved to MyModel._mptt_meta

Most people won’t need to worry about this, but if you’re using any of the following, note that these are deprecated and will be removed in 0.5:

MyModel._meta.left_attr
MyModel._meta.right_attr
MyModel._meta.tree_id_attr
MyModel._meta.level_attr
MyModel._meta.tree_manager_attr
MyModel._meta.parent_attr
MyModel._meta.order_insertion_by

They’ll continue to work as previously for now, but you should upgrade your code if you can. Simply replace _meta with _mptt_meta.

Use model inheritance where possible

The preferred way to do model registration in django-mptt 0.4 is via model inheritance.

Suppose you start with this:

class Node(models.Model):
    ...

mptt.register(Node, order_insertion_by=['name'], parent_attr='padre')

First, Make your model a subclass of MPTTModel, instead of models.Model:

from mptt.models import MPTTModel

class Node(MPTTModel):
    ...

Then remove your call to mptt.register(). If you were passing it keyword arguments, you should add them to an MPTTMeta inner class on the model:

class Node(MPTTModel):
    ...
    class MPTTMeta:
        order_insertion_by = ['name']
        parent_attr = 'padre'

If necessary you can still use mptt.register. It was removed in 0.4.0 but restored in 0.4.2, since people reported use cases that didn’t work without it.)

For instance, if you need to register models where the code isn’t under your control, you’ll need to use mptt.register().

Behind the scenes, mptt.register() in 0.4 will actually add MPTTModel to Node.__bases__, thus achieving the same result as subclassing MPTTModel. If you’re already inheriting from something other than Model, that means multiple inheritance.

You’re probably all upgraded at this point :) A couple more notes for more complex scenarios:

More complicated scenarios

What if I’m already inheriting from something?

If your model is already a subclass of an abstract model, you should use multiple inheritance:

class Node(MPTTModel, ParentModel):
    ...

You should always put MPTTModel as the first model base. This is because there’s some complicated metaclass stuff going on behind the scenes, and if Django’s model metaclass gets called before the MPTT one, strange things can happen.

Isn’t multiple inheritance evil? Well, maybe. However, the Django model docs don’t forbid this, and as long as your other model doesn’t have conflicting methods, it should be fine.

Note

As always when dealing with multiple inheritance, approach with a bit of caution.

Our brief testing says it works, but if you find that the Django internals are somehow breaking this approach for you, please create an issue with specifics.

Compatibility with 0.3

MPTTModel was added in 0.4. If you’re writing a library or reusable app that needs to work with 0.3, you should use the mptt.register() function instead, as above.