/
repair_tree.py
166 lines (140 loc) · 5.97 KB
/
repair_tree.py
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from __future__ import annotations
import logging
from typing import TYPE_CHECKING
from django.core.management.base import CommandError
from ....cms.models import Page
from ..log_command import LogCommand
if TYPE_CHECKING:
from typing import Any
from django.core.management.base import CommandParser
logger = logging.getLogger(__name__)
class Command(LogCommand):
"""
Management command to repair a broken Treebeard page tree
"""
help = "Repair broken tree structure"
pages_seen: list[int] = []
def add_arguments(self, parser: CommandParser) -> None:
"""
Define the arguments of this command
:param parser: The argument parser
"""
parser.add_argument(
"page_id", type=int, help="The ID of a page belonging to the broken tree."
)
parser.add_argument(
"--commit",
action="store_true",
help="Whether changes should be written to the database",
)
# pylint: disable=arguments-differ
def handle(self, *args: Any, page_id: int, commit: bool, **options: Any) -> None:
r"""
Try to run the command
:param \*args: The supplied arguments
:param page_id: The page ID (node) of a broken tree
:param commit: Whether changes should be written to the database
:param \**options: The supplied keyword options
:raises ~django.core.management.base.CommandError: When the input is invalid
"""
self.set_logging_stream()
try:
root_node = Page.objects.get(id=page_id)
except Page.DoesNotExist as e:
raise CommandError(f'The page with id "{page_id}" does not exist.') from e
# Traversing to root node
while root_node.parent:
root_node = root_node.parent
action = "Fixing" if commit else "Detecting problems in"
logger.info("%s tree with id %s...", action, root_node.tree_id)
self.calculate_left_right_values(root_node, 1, commit)
self.check_for_orphans(root_node.tree_id)
def check_tree_fields(self, tree_node: Page, left: int, right: int) -> bool:
"""
Check whether the tree fields are correct
:param tree_node: The current node
:param left: The new left value of the node
:param right: The new right value of the node
:return: Whether the tree fields of the node are valid
"""
valid = True
logger.info("Page %s:", tree_node.id)
logger.success("\tparent_id: %s", tree_node.parent_id) # type: ignore[attr-defined]
if not tree_node.parent or tree_node.tree_id == tree_node.parent.tree_id:
logger.success("\ttree_id: %s", tree_node.tree_id) # type: ignore[attr-defined]
else:
logger.error(
"\ttree_id: %s → %s", tree_node.tree_id, tree_node.parent.tree_id
)
valid = False
if tree_node.parent_id:
if tree_node.depth == tree_node.parent.depth + 1:
logger.success("\tdepth: %s", tree_node.depth) # type: ignore[attr-defined]
else:
logger.error(
"\tdepth: %s → %s", tree_node.depth, tree_node.parent.depth + 1
)
valid = False
elif tree_node.depth == 1:
logger.success("\tdepth: %s", tree_node.depth) # type: ignore[attr-defined]
else:
logger.error("\tdepth: %s → 1", tree_node.depth)
valid = False
if tree_node.lft == left:
logger.success("\tlft: %s", tree_node.lft) # type: ignore[attr-defined]
else:
logger.error("\tlft: %s → %s", tree_node.lft, left)
valid = False
if tree_node.rgt == right:
logger.success("\trgt: %s", tree_node.rgt) # type: ignore[attr-defined]
else:
logger.error("\trgt: %s → %s", tree_node.rgt, right)
valid = False
return valid
def check_for_orphans(self, tree_id: int) -> None:
"""
Check whether orphans exist (pages with the same tree_id, but its ancestors are in another tree)
:param tree_id: The current tree id
"""
if orphans := Page.objects.filter(tree_id=tree_id).exclude(
id__in=self.pages_seen
):
logger.error(
"\n💣 Orphans detected! The following pages share the tree id "
"%s but don't have a relation to the root node:",
tree_id,
)
for orphan in orphans:
logger.info("Page %s:", orphan.id)
logger.error("\tparent_id: %s", orphan.parent_id)
if orphan.parent_id:
logger.error("\tparent.tree_id: %s", orphan.parent.tree_id)
logger.info("\tdepth %s", orphan.depth)
logger.info("\tlft: %s", orphan.lft)
logger.info("\trgt: %s", orphan.rgt)
def calculate_left_right_values(
self, tree_node: Page, left: int, commit: bool
) -> int:
"""
Recursively calculate the left and right value for a given node and its
children.
:param tree_node: A node of a MPTT tree
:param left: The new left value of the node
:param commit: Whether changes should be written to the database
:return: The new right value of the node
"""
right = left
for child in tree_node.children.all():
right = self.calculate_left_right_values(child, right + 1, commit)
right += 1
valid = self.check_tree_fields(tree_node, left, right)
if not valid and commit:
if tree_node.parent:
tree_node.tree_id = tree_node.parent.tree_id
tree_node.depth = tree_node.parent.depth + 1
tree_node.rgt = right
tree_node.lft = left
tree_node.save()
logger.info("Fixed tree fields of %r", tree_node)
self.pages_seen.append(tree_node.id)
return right