Fix parent error when deleting category

- Any child categories have their parent set to the parent of the deleted category

InvenTree/InvenTree/models.py

@@ -4,6 +4,8 @@ from django.db import models
 from django.contrib.contenttypes.models import ContentType
 from rest_framework.exceptions import ValidationError
 
+from django.db.models.signals import pre_delete
+from django.dispatch import receiver
 
 class Company(models.Model):
     """ Abstract model representing an external company
@@ -40,9 +42,12 @@ class InvenTreeTree(models.Model):
         unique_together = ('name', 'parent')
 
     name = models.CharField(max_length=100, unique=True)
+
     description = models.CharField(max_length=250, blank=True)
+
+    # When a category is deleted, graft the children onto its parent
     parent = models.ForeignKey('self',
-                               on_delete=models.CASCADE,
+                               on_delete=models.DO_NOTHING,
                                blank=True,
                                null=True,
                                related_name='children')
@@ -179,6 +184,15 @@ class InvenTreeTree(models.Model):
         return self.pathstring
 
 
+@receiver(pre_delete, sender=InvenTreeTree, dispatch_uid='tree_pre_delete_log')
+def before_delete_tree_item(sender, intance, using, **kwargs):
+
+    # Update each tree item below this one
+    for child in instance.children.all():
+        child.parent = instance.parent
+        child.save()
+
+
 def FilterChildren(queryset, parent):
     """ Filter a queryset, limit to only objects that are a child of the given parent
     Filter is passed in the URL string, e.g. '/?parent=123'

InvenTree/part/migrations/0014_auto_20180415_0107.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11 on 2018-04-15 01:07
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0013_auto_20180414_2238'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='partcategory',
+            name='parent',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.DO_NOTHING, related_name='children', to='part.PartCategory'),
+        ),
+    ]

InvenTree/part/models.py

@@ -16,6 +16,9 @@ class PartCategory(InvenTreeTree):
     """ PartCategory provides hierarchical organization of Part objects.
     """
 
+    def get_absolute_url(self):
+        return '/part/category/{id}/'.format(id=self.id)
+
     class Meta:
         verbose_name = "Part Category"
         verbose_name_plural = "Part Categories"
@@ -48,6 +51,11 @@ def before_delete_part_category(sender, instance, using, **kwargs):
         part.category = instance.parent
         part.save()
 
+    # Update each child category
+    for child in instance.children.all():
+        child.parent = instance.parent
+        child.save()
+
 
 # Function to automatically rename a part image on upload
 # Format: part_pk.<img>

InvenTree/stock/migrations/0005_auto_20180415_0107.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11 on 2018-04-15 01:07
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0004_auto_20180414_1032'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='stocklocation',
+            name='parent',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.DO_NOTHING, related_name='children', to='stock.StockLocation'),
+        ),
+    ]