django-mptt: how to successfully move nodes around
- by Parand
django-mptt seems determined to drive me out of my mind. I'm trying to do something relatively simple: I'm going to delete a node, and need to do something reasonable with the node's children. Namely, I'd like to move them up one level so they're children of their current parent's parent.
That is, if the tree looks like:
Root
|
Grandpa
|
Father
| |
C1 C2
I'm going to delete Father, and would like C1 and C2 to be children of Grandpa.
Here's the code I'm using:
class Node(models.Model):
first_name = models.CharField(max_length=80, blank=True)
parent = models.ForeignKey('self', null=True, blank=True, related_name='children')
def reparent_children(self, parent):
print "Reparenting"
for child in self.get_children():
print "Working on", child.first_name, "to parent", parent.email
parent = Node.objects.get(id=parent.id)
child.move_to(parent, 'last-child')
child.save()
So I'd call:
father.reparent_children(grandpa)
father.parent = None
father.save()
This works - almost. The children report their parents as Grandpa:
c1.parent == grandpa # True
Grandpa counts C1 and C2 among its children
c1 in grandpa.children.all() # True
However, Root disowns these kids.
c1.get_root() == father # c1's root is father, instead of Root
c1 in root.get_descendants() # False
How do I get the children to move and their root not get corrupted?
