Desktop,Mobile,Cli: Fix notes are moved to the conflict folder when a folder is unshared (#12993)

Co-authored-by: Laurent Cozic <laurent22@users.noreply.github.com>

packages/lib/models/Folder.sharing.test.ts

@@ -505,7 +505,7 @@ describe('models/Folder.sharing', () => {
 		expect(note4.user_updated_time).toBe(userUpdatedTimes[note4.id]);
 	});
 
-	it('should unshare items that are no longer part of an existing share', async () => {
+	it('should clear share_ids for items that are no longer part of an existing share', async () => {
 		await createFolderTree('', [
 			{
 				title: 'folder 1',
@@ -591,4 +591,34 @@ describe('models/Folder.sharing', () => {
 		}
 	});
 
+	it('should not change the updated_time when clearing share_ids for no-longer-shared items', async () => {
+		await createFolderTree('', [
+			{
+				title: 'folder 1',
+				share_id: '1',
+				children: [
+					{
+						title: 'note 1',
+					},
+				],
+			},
+		]);
+
+		await Folder.updateAllShareIds(resourceService(), []);
+
+		const folder1 = await Folder.loadByTitle('folder 1');
+		const note1 = await Note.loadByTitle('note 1');
+		await Folder.updateNoLongerSharedItems([]);
+
+		// To avoid conflicts, should not change the updated_time
+		expect(await Note.loadByTitle('note 1')).toMatchObject({
+			updated_time: note1.updated_time,
+			share_id: '',
+		});
+		expect(await Folder.loadByTitle('folder 1')).toMatchObject({
+			updated_time: folder1.updated_time,
+			share_id: '',
+		});
+	});
+
 });

packages/lib/models/Folder.ts

@@ -1,4 +1,4 @@
-import { defaultFolderIcon, FolderEntity, FolderIcon, NoteEntity, ResourceEntity } from '../services/database/types';
+import { BaseItemEntity, defaultFolderIcon, FolderEntity, FolderIcon, NoteEntity, ResourceEntity } from '../services/database/types';
 import BaseModel, { DeleteOptions } from '../BaseModel';
 import { FolderLoadOptions } from './utils/types';
 import time from '../time';
@@ -747,14 +747,18 @@ export default class Folder extends BaseItem {
 			report[tableName] = rows.length;
 
 			for (const row of rows) {
-				// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied
+				const toSave: BaseItemEntity = {
-				const toSave: any = {
 					id: row.id,
 					share_id: '',
-					updated_time: Date.now(),
+					// Don't change the updated_time.
+					// This prevents conflicts in the case where the item was unshared remotely.
+					// See https://github.com/laurent22/joplin/issues/12648
+					// updated_time: Date.now(),
 				};
 
-				if (hasParentId) toSave.parent_id = row.parent_id;
+				if (hasParentId) {
+					(toSave as FolderEntity|NoteEntity).parent_id = row.parent_id;
+				}
 
 				await ItemClass.save(toSave, { autoTimestamp: false });
 			}

readme/dev/spec/server_sharing.md

@@ -25,6 +25,18 @@ Technically, the server would only need to know the root shared folder, and from
 
 On the other hand, all that information is present on the client. Whenever a notes is moved out a shared folder, or whenever a resources is attached, the changes are tracked, and that can be used to easily assign a `share_id` property. Once this is set, it makes the whole system more simple and reliable.
 
+### When are changes to `share_id` synced?
+
+In general, changes to `share_id` should be synced only if a Joplin client still has access to the remote item. For example, if `User1` adds an item to a folder shared with `User2`, then `User1` should update and sync the `share_id` for that item.
+
+However, there are some maintenance tasks that clear `share_id` locally when a user no longer has access to a share. These changes should not be synced to the server because the user no longer has access to the relevant remote items. For example, if,
+1. `User1` shares `Folder A` with `User2`.
+2. `User2` accepts the share.
+3. `User1` unshares `Folder A`.
+4. `User2` locally clears the `share_id` property on the local `Folder A`.
+
+At this point, `User2` no longer has access to `Folder A` on the server. They cannot sync the change to `share_id` because they no longer have access to the share.
+
 ## Publishing a note via a public URL 
 
 This is done by posting a note ID to `/api/shares`.