def _get_path_info_with_parent(self):
"""
Return the path that joins the current model through any parent models.
The idea is that if you have a GFK defined on a parent model then we
need to join the parent model first, then the child model.
"""
# With an inheritance chain ChildTag -> Tag and Tag defines the
# GenericForeignKey, and a TaggedItem model has a GenericRelation to
# ChildTag, then we need to generate a join from TaggedItem to Tag
# (as Tag.object_id == TaggedItem.pk), and another join from Tag to
# ChildTag (as that is where the relation is to). Do this by first
# generating a join to the parent model, then generating joins to the
# child models.
path = []
opts = self.remote_field.model._meta
parent_opts = opts.get_field(self.object_id_field_name).model._meta
target = parent_opts.pk
path.append(PathInfo(self.model._meta, parent_opts, (target,), self.remote_field, True, False))
# Collect joins needed for the parent -> child chain. This is easiest
# to do if we collect joins for the child -> parent chain and then
# reverse the direction (call to reverse() and use of
# field.remote_field.get_path_info()).
parent_field_chain = []
while parent_opts != opts:
field = opts.get_ancestor_link(parent_opts.model)
parent_field_chain.append(field)
opts = field.remote_field.model._meta
parent_field_chain.reverse()
for field in parent_field_chain:
path.extend(field.remote_field.get_path_info())
return path
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