Handle conflict resolution for remote item deletions

chrome/content/zotero/xpcom/sync/syncEngine.js

@@ -325,6 +325,7 @@ Zotero.Sync.Data.Engine.prototype._startDownload = Zotero.Promise.coroutine(func
 				let objectType = Zotero.DataObjectUtilities.getObjectTypeSingular(objectTypePlural);
 				let objectsClass = Zotero.DataObjectUtilities.getObjectsClassForObjectType(objectType);
 				let toDelete = [];
+				let conflicts = [];
 				for (let key of results.deleted[objectTypePlural]) {
 					// TODO: Remove from request?
 					if (objectType == 'tag') {
@@ -357,11 +358,55 @@ Zotero.Sync.Data.Engine.prototype._startDownload = Zotero.Promise.coroutine(func
 					}
 					// Conflict resolution
 					else if (objectType == 'item') {
-						throw new Error("Unimplemented: delete conflict");
+						conflicts.push({
+							left: yield obj.toJSON(),
+							right: {
+								deleted: true
+							}
+						});
 					}
 					
 					// Ignore deletion if collection/search changed locally
 				}
+				
+				if (conflicts.length) {
+					conflicts.sort(function (a, b) {
+						var d1 = a.left.dateModified;
+						var d2 = b.left.dateModified;
+						if (d1 > d2) {
+							return 1
+						}
+						if (d1 < d2) {
+							return -1;
+						}
+						return 0;
+					});
+					var mergeData = Zotero.Sync.Data.Local.resolveConflicts(conflicts);
+					if (mergeData) {
+						let concurrentObjects = 50;
+						yield Zotero.Utilities.Internal.forEachChunkAsync(
+							mergeData,
+							concurrentObjects,
+							function (chunk) {
+								return Zotero.DB.executeTransaction(function* () {
+									for (let json of chunk) {
+										if (!json.deleted) continue;
+										let obj = yield objectsClass.getByLibraryAndKeyAsync(
+											this.libraryID, json.key, { noCache: true }
+										);
+										if (!obj) {
+											Zotero.logError("Remotely deleted " + objectType
+												+ " didn't exist after conflict resolution");
+											continue;
+										}
+										yield obj.erase();
+									}
+								}.bind(this));
+							}.bind(this)
+						);
+					}
+				}
+				
 				if (toDelete.length) {
 					yield Zotero.DB.executeTransaction(function* () {
 						for (let obj of toDelete) {

test/tests/syncEngineTest.js

@@ -741,6 +741,88 @@ describe("Zotero.Sync.Data.Engine", function () {
 			assert.ok(Zotero.Collections.exists(collectionID));
 			assert.ok(Zotero.Searches.exists(searchID));
 		})
+		
+		it("should show conflict resolution window for conflicting remote deletions", function* () {
+			var userLibraryID = Zotero.Libraries.userLibraryID;
+			yield Zotero.Libraries.setVersion(userLibraryID, 5);
+			({ engine, client, caller } = yield setup());
+			
+			// Create local unsynced items
+			var item = createUnsavedDataObject('item');
+			item.setField('title', 'A');
+			item.synced = false;
+			var itemID1 = yield item.saveTx({ skipSyncedUpdate: true });
+			var itemKey1 = item.key;
+			
+			item = createUnsavedDataObject('item');
+			item.setField('title', 'B');
+			item.synced = false;
+			var itemID2 = yield item.saveTx({ skipSyncedUpdate: true });
+			var itemKey2 = item.key;
+			
+			var headers = {
+				"Last-Modified-Version": 6
+			};
+			setResponse({
+				method: "GET",
+				url: "users/1/settings?since=5",
+				status: 200,
+				headers: headers,
+				json: {}
+			});
+			setResponse({
+				method: "GET",
+				url: "users/1/collections?format=versions&since=5",
+				status: 200,
+				headers: headers,
+				json: {}
+			});
+			setResponse({
+				method: "GET",
+				url: "users/1/searches?format=versions&since=5",
+				status: 200,
+				headers: headers,
+				json: {}
+			});
+			setResponse({
+				method: "GET",
+				url: "users/1/items?format=versions&since=5&includeTrashed=1",
+				status: 200,
+				headers: headers,
+				json: {}
+			});
+			setResponse({
+				method: "GET",
+				url: "users/1/deleted?since=5",
+				status: 200,
+				headers: headers,
+				json: {
+					settings: [],
+					collections: [],
+					searches: [],
+					items: [itemKey1, itemKey2]
+				}
+			});
+			
+			waitForWindow('chrome://zotero/content/merge.xul', function (dialog) {
+				var doc = dialog.document;
+				var wizard = doc.documentElement;
+				var mergeGroup = wizard.getElementsByTagName('zoteromergegroup')[0];
+				
+				// 1 (accept remote deletion)
+				assert.equal(mergeGroup.leftpane.getAttribute('selected'), 'true');
+				mergeGroup.rightpane.click();
+				wizard.getButton('next').click();
+				
+				// 2 (ignore remote deletion)
+				assert.equal(mergeGroup.leftpane.getAttribute('selected'), 'true');
+				wizard.getButton('finish').click();
+			})
+			yield engine._startDownload();
+			
+			assert.isFalse(Zotero.Items.exists(itemID1));
+			assert.isTrue(Zotero.Items.exists(itemID2));
+		})
 	})
 	
 	describe("#_upgradeCheck()", function () {