Improve sync conflict handling when the changes between local and remote don't matter

CliClient/app/command-edit.js

@@ -75,7 +75,7 @@ class Command extends BaseCommand {
 			this.logger().info('Disabling fullscreen...');
 
 			app().gui().showModalOverlay(_('Starting to edit note. Close the editor to get back to the prompt.'));
-			app().gui().forceRender();
+			await app().gui().forceRender();
 			const termState = app().gui().term().saveState();
 
 			const spawnSync	= require('child_process').spawnSync;

CliClient/tests/synchronizer.js

@@ -568,4 +568,44 @@ describe('Synchronizer', function() {
 		done();
 	});
 
+	it('should not consider it is a conflict if neither the title nor body of the note have changed', async (done) => {
+		// That was previously a common conflict:
+		// - Client 1 mark todo as "done", and sync
+		// - Client 2 doesn't sync, mark todo as "done" todo. Then sync.
+		// In theory it is a conflict because the todo_completed dates are different
+		// but in practice it doesn't matter, we can just take the date when the
+		// todo was marked as "done" the first time.
+
+		let folder1 = await Folder.save({ title: "folder1" });
+		let note1 = await Note.save({ title: "un", is_todo: 1, parent_id: folder1.id });
+		await synchronizer().start();
+
+		await switchClient(2);
+
+		await synchronizer().start();
+		let note2 = await Note.load(note1.id);
+		note2.todo_completed = time.unixMs()-1;
+		await Note.save(note2);
+		note2 = await Note.load(note2.id);
+		await synchronizer().start();
+
+		await switchClient(1);
+
+		let note2conf = await Note.load(note1.id);
+		note2conf.todo_completed = time.unixMs();
+		await Note.save(note2conf);
+		note2conf = await Note.load(note1.id);
+		await synchronizer().start();
+
+		let conflictedNotes = await Note.conflictedNotes();
+		expect(conflictedNotes.length).toBe(0);
+
+		let notes = await Note.all();
+		expect(notes.length).toBe(1);
+		expect(notes[0].id).toBe(note1.id);
+		expect(notes[0].todo_completed).toBe(note2.todo_completed);
+
+		done();
+	});
+	
 });

CliClientDemo/package.json

@@ -16,7 +16,7 @@
     "node": ">=8.7.0"
   },
   "copyright": {
-    "title": "Joplin CLI",
+    "title": "Demo for Joplin CLI",
     "years": [
       2016,
       2017

ReactNativeClient/lib/models/base-item.js

@@ -280,7 +280,7 @@ class BaseItem extends BaseModel {
 			output.title = title[0];
 		}
 
-		if (body.length) output.body = body.join("\n");
+		if (output.type_ === BaseModel.TYPE_NOTE) output.body = body.join("\n");
 
 		for (let n in output) {
 			if (!output.hasOwnProperty(n)) continue;

ReactNativeClient/lib/models/note.js

@@ -415,6 +415,17 @@ class Note extends BaseItem {
 		return result;
 	}
 
+	// Tells whether the conflict between the local and remote note can be ignored.
+	static mustHandleConflict(localNote, remoteNote) {
+		// That shouldn't happen so throw an exception
+		if (localNote.id !== remoteNote.id) throw new Error('Cannot handle conflict for two different notes');
+
+		if (localNote.title !== remoteNote.title) return true;
+		if (localNote.body !== remoteNote.body) return true;
+
+		return false;
+	}
+
 }
 
 Note.updateGeolocationEnabled_ = true;

ReactNativeClient/lib/synchronizer.js

@@ -57,7 +57,6 @@ class Synchronizer {
 		if (report.deleteLocal) lines.push(_('Deleted local items: %d.', report.deleteLocal));
 		if (report.deleteRemote) lines.push(_('Deleted remote items: %d.', report.deleteRemote));
 		if (!report.completedTime && report.state) lines.push(_('State: "%s".', report.state));
-		//if (report.errors && report.errors.length) lines.push(_('Last error: %s (stacktrace in log).', report.errors[report.errors.length-1].message));
 		if (report.cancelling && !report.completedTime) lines.push(_('Cancelling...'));
 		if (report.completedTime) lines.push(_('Completed: %s', time.unixMsToLocalDateTime(report.completedTime)));
 
@@ -125,17 +124,6 @@ class Synchronizer {
 		}
 	}
 
-	randomFailure(options, name) {
-		if (!options.randomFailures) return false;
-
-		if (this.randomFailureChoice_ == name) {
-			options.onMessage('Random failure: ' + name);
-			return true;
-		}
-
-		return false;
-	}
-
 	async cancel() {
 		if (this.cancelling_ || this.state() == 'idle') return;
 		
@@ -175,7 +163,6 @@ class Synchronizer {
 
 		const syncTargetId = this.api().syncTargetId();
 
-		this.randomFailureChoice_ = Math.floor(Math.random() * 5);
 		this.cancelling_ = false;
 
 		// ------------------------------------------------------------------------
@@ -187,7 +174,6 @@ class Synchronizer {
 
 		let outputContext = Object.assign({}, lastContext);
 		
-
 		this.dispatch({ type: 'SYNC_STARTED' });
 
 		this.logSyncOperation('starting', null, null, 'Starting synchronisation to target ' + syncTargetId + '... [' + synchronizationId + ']');
@@ -225,13 +211,14 @@ class Synchronizer {
 							reason = 'remote does not exist, and local is new and has never been synced';
 						} else {
 							// Note or item was modified after having been deleted remotely
+							// "itemConflict" if for all the items except the notes, which are dealt with in a special way
 							action = local.type_ == BaseModel.TYPE_NOTE ? 'noteConflict' : 'itemConflict';
 							reason = 'remote has been deleted, but local has changes';
 						}
 					} else {
 						if (remote.updated_time > local.sync_time) {
-							// Since, in this loop, we are only dealing with notes that require sync, if the
-							// remote has been modified after the sync time, it means both notes have been
+							// Since, in this loop, we are only dealing with items that require sync, if the
+							// remote has been modified after the sync time, it means both items have been
 							// modified and so there's a conflict.
 							action = local.type_ == BaseModel.TYPE_NOTE ? 'noteConflict' : 'itemConflict';
 							reason = 'both remote and local have changes';
@@ -276,13 +263,7 @@ class Synchronizer {
 						// await this.api().move(tempPath, path);
 
 						await this.api().put(path, content);
-
-						if (this.randomFailure(options, 0)) return;
-
 						await this.api().setTimestamp(path, local.updated_time);
-
-						if (this.randomFailure(options, 1)) return;
-
 						await ItemClass.saveSyncTime(syncTargetId, local, time.unixMs());
 
 					} else if (action == 'itemConflict') {
@@ -299,22 +280,43 @@ class Synchronizer {
 
 					} else if (action == 'noteConflict') {
 
-						// - Create a duplicate of local note into Conflicts folder (to preserve the user's changes)
-						// - Overwrite local note with remote note
-						let conflictedNote = Object.assign({}, local);
-						delete conflictedNote.id;
-						conflictedNote.is_conflict = 1;
-						await Note.save(conflictedNote, { autoTimestamp: false });
+						// ------------------------------------------------------------------------------
+						// First find out if the conflict matters. For example, if the conflict is on the title or body
+						// we want to preserve all the changes. If it's on todo_completed it doesn't really matter
+						// so in this case we just take the remote content.
+						// ------------------------------------------------------------------------------
 
-						if (this.randomFailure(options, 2)) return;
+						let loadedRemote = null;
+						let mustHandleConflict = true;
+						if (remote) {
+							const remoteContent = await this.api().get(path);
+							loadedRemote = await BaseItem.unserialize(remoteContent);
+							mustHandleConflict = Note.mustHandleConflict(local, loadedRemote);
+						}
+
+						// ------------------------------------------------------------------------------
+						// Create a duplicate of local note into Conflicts folder
+						// (to preserve the user's changes)
+						// ------------------------------------------------------------------------------
+
+						if (mustHandleConflict) {
+							let conflictedNote = Object.assign({}, local);
+							delete conflictedNote.id;
+							conflictedNote.is_conflict = 1;
+							await Note.save(conflictedNote, { autoTimestamp: false });
+						}
+
+						// ------------------------------------------------------------------------------
+						// Either copy the remote content to local or, if the remote content has
+						// been deleted, delete the local content.
+						// ------------------------------------------------------------------------------
 
 						if (remote) {
-							let remoteContent = await this.api().get(path);
-							local = await BaseItem.unserialize(remoteContent);
-
+							local = loadedRemote;
 							const syncTimeQueries = BaseItem.updateSyncTimeQueries(syncTargetId, local, time.unixMs());
 							await ItemClass.save(local, { autoTimestamp: false, nextQueries: syncTimeQueries });
 						} else {
+							// Remote no longer exists (note deleted) so delete local one too
 							await ItemClass.delete(local.id);
 						}
 
@@ -338,7 +340,6 @@ class Synchronizer {
 				let path = BaseItem.systemPath(item.item_id)
 				this.logSyncOperation('deleteRemote', null, { id: item.item_id }, 'local has been deleted');
 				await this.api().delete(path);
-				if (this.randomFailure(options, 3)) return;
 				await BaseItem.remoteDeletedItem(syncTargetId, item.item_id);
 			}