fix: Unassign flow folders before removing folder

packages/backend/src/controllers/api/v1/folders/delete-folder.js

@@ -4,7 +4,7 @@ export default async (request, response) => {
     .findById(request.params.folderId)
     .throwIfNotFound();
 
-  await folder.$query().delete();
+  await folder.delete();
 
   response.status(204).end();
 };

packages/backend/src/models/folder.js

@@ -1,5 +1,6 @@
 import Base from './base.js';
 import User from './user.js';
+import Flow from './flow.js';
 
 class Folder extends Base {
   static tableName = 'folders';
@@ -24,7 +25,20 @@ class Folder extends Base {
         to: 'users.id',
       },
     },
+    flows: {
+      relation: Base.HasManyRelation,
+      modelClass: Flow,
+      join: {
+        from: 'folders.id',
+        to: 'flows.folder_id',
+      },
+    },
   });
+
+  async delete() {
+    await this.$relatedQuery('flows').patch({ folderId: null });
+    await this.$query().delete();
+  }
 }
 
 export default Folder;

packages/backend/src/models/folder.test.js

@@ -1,7 +1,11 @@
 import { describe, it, expect } from 'vitest';
 import Folder from './folder';
 import User from './user';
+import Flow from './flow';
 import Base from './base';
+import { createFolder } from '../../test/factories/folder';
+import { createFlow } from '../../test/factories/flow';
+import { createUser } from '../../test/factories/user';
 
 describe('Folder model', () => {
   it('tableName should return correct name', () => {
@@ -24,8 +28,40 @@ describe('Folder model', () => {
           to: 'users.id',
         },
       },
+      flows: {
+        relation: Base.HasManyRelation,
+        modelClass: Flow,
+        join: {
+          from: 'folders.id',
+          to: 'flows.folder_id',
+        },
+      },
     };
 
     expect(relationMappings).toStrictEqual(expectedRelations);
   });
+
+  describe('delete', () => {
+    it('should set folderId to null for all related flows before deleting the folder', async () => {
+      const user = await createUser();
+
+      const folder = await createFolder({ userId: user.id });
+      const flow = await createFlow({ folderId: folder.id, userId: user.id });
+
+      await folder.delete();
+
+      const refetchedFlow = await flow.$query();
+      expect(refetchedFlow.folderId).toBe(null);
+    });
+
+    it('should delete the folder', async () => {
+      const user = await createUser();
+      const folder = await createFolder({ userId: user.id });
+
+      await folder.delete();
+
+      const deletedFolder = await Folder.query().findById(folder.id);
+      expect(deletedFolder).toBeUndefined();
+    });
+  });
 });