fix: 添加迁移文件（如果需要，将Default节点的key从0修改为1)

apps/assets/migrations/0063_migrate_default_node_key.py

@@ -0,0 +1,72 @@
+# Generated by Jiangjie.Bai on 2020-12-01 10:47
+
+from django.db import migrations
+from django.db.models import Q
+
+default_node_value = 'Default'  # Always
+old_default_node_key = '0'  # Version <= 1.4.3
+new_default_node_key = '1'  # Version >= 1.4.4
+
+
+def compute_parent_key(key):
+    try:
+        return key[:key.rindex(':')]
+    except ValueError:
+        return ''
+
+
+def migrate_default_node_key(apps, schema_editor):
+    """ 将已经存在的Default节点的key从0修改为1 """
+    # 1.4.3版本中Default节点的key为0
+    print('')
+    Node = apps.get_model('assets', 'Node')
+    Asset = apps.get_model('assets', 'Asset')
+
+    # key为0的节点
+    old_default_node = Node.objects.filter(key=old_default_node_key, value=default_node_value).first()
+    if not old_default_node:
+        print(f'Check old default node `key={old_default_node_key} value={default_node_value}` not exists')
+        return
+    print(f'Check old default node `key={old_default_node_key} value={default_node_value}` exists')
+    # key为1的节点
+    new_default_node = Node.objects.filter(key=new_default_node_key, value=default_node_value).first()
+    if new_default_node:
+        print(f'Check new default node `key={new_default_node_key} value={default_node_value}` exists')
+        all_assets = Asset.objects.filter(
+            Q(nodes__key__startswith=f'{new_default_node_key}:') | Q(nodes__key=new_default_node_key)
+        ).distinct()
+        if all_assets:
+            print(f'Check new default node has assets (count: {len(all_assets)})')
+            return
+        all_children = Node.objects.filter(Q(key__startswith=f'{new_default_node_key}:'))
+        if all_children:
+            print(f'Check new default node has children nodes (count: {len(all_children)})')
+            return
+        print(f'Check new default node not has assets and children nodes, delete it.')
+        new_default_node.delete()
+    # 执行修改
+    print(f'Modify old default node key from `{old_default_node_key}` to `{new_default_node_key}`')
+    nodes = Node.objects.filter(
+        Q(key__istartswith=f'{old_default_node_key}:') | Q(key=old_default_node_key)
+    )
+    for node in nodes:
+        old_key = node.key
+        key_list = old_key.split(':', maxsplit=1)
+        key_list[0] = new_default_node_key
+        new_key = ':'.join(key_list)
+        node.key = new_key
+        node.parent_key = compute_parent_key(node.key)
+    # 批量更新
+    Node.objects.bulk_update(nodes, ['key', 'parent_key'])
+    print('Bulk update key and parent_key')
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('assets', '0062_auto_20201117_1938'),
+    ]
+
+    operations = [
+        migrations.RunPython(migrate_default_node_key)
+    ]