WIP

backend/sync_server/src/server/delete_document.rs

@@ -10,7 +10,7 @@ use serde::Deserialize;
 
 use super::{app_state::AppState, auth::auth, requests::DeleteDocumentVersion};
 use crate::{
-    database::models::{DocumentId, StoredDocumentVersion, VaultId},
+    database::models::{DocumentId, DocumentVersionWithoutContent, StoredDocumentVersion, VaultId},
     errors::{SyncServerError, server_error},
     utils::sanitize_path,
 };
@@ -31,7 +31,7 @@ pub async fn delete_document(
     }): Path<PathParams>,
     State(state): State<AppState>,
     Json(request): Json<DeleteDocumentVersion>,
-) -> Result<(), SyncServerError> {
+) -> Result<Json<DocumentVersionWithoutContent>, SyncServerError> {
     auth(&state, auth_header.token())?;
 
     let mut transaction = state
@@ -69,5 +69,5 @@ pub async fn delete_document(
         .context("Failed to commit successful transaction")
         .map_err(server_error)?;
 
-    Ok(())
+    Ok(Json(new_version.into()))
 }

backend/sync_server/src/server/update_document.rs

@@ -138,6 +138,18 @@ async fn internal_update_document(
             Ok,
         )?;
 
+    if latest_version.is_deleted {
+        transaction
+            .rollback()
+            .await
+            .context("Failed to roll back transaction")
+            .map_err(server_error)?;
+
+        return Ok(Json(DocumentUpdateResponse::FastForwardUpdate(
+            latest_version.into(),
+        )));
+    }
+
     let sanitized_relative_path = sanitize_path(&relative_path);
 
     // Return the latest version if the content and path are the same as the latest
@@ -195,7 +207,7 @@ async fn internal_update_document(
         content: merged_content,
         created_date,
         updated_date: chrono::Utc::now(),
-        is_deleted: latest_version.is_deleted,
+        is_deleted: false,
     };
 
     state

frontend/sync-client/src/file-operations/file-operations.test.ts

@@ -1,17 +1,27 @@
 import type { FileSystemOperations } from "sync-client";
-import type { Database, RelativePath } from "../persistence/database";
+import type {
+	Database,
+	DocumentMetadata,
+	RelativePath
+} from "../persistence/database";
 import { FileOperations } from "./file-operations";
 import { Logger } from "../tracing/logger";
 import { assertSetContainsExactly } from "../utils/assert-set-contains-exactly";
 
 describe("File operations", () => {
 	class MockDatabase {
-		public async updatePath(
+		public async move(
 			_oldRelativePath: RelativePath,
 			_newRelativePath: RelativePath
 		): Promise<void> {
 			// this is called but irrelevant for this mock
 		}
+
+		public getResolvedDocument(
+			_relativePath: RelativePath | undefined
+		): DocumentMetadata | undefined {
+			return undefined;
+		}
 	}
 
 	class FakeFileSystemOperations implements FileSystemOperations {

frontend/sync-client/src/file-operations/file-operations.ts

@@ -6,7 +6,10 @@ import type {
 	RelativePath
 } from "src/persistence/database";
 import { isBinary, isFileTypeMergable, mergeText } from "sync_lib";
-import { SafeFileSystemOperations } from "./safe-filesystem-operations";
+import {
+	FileNotFoundError,
+	SafeFileSystemOperations
+} from "./safe-filesystem-operations";
 
 export class FileOperations {
 	private static readonly PARENTHESES_REGEX = / \((\d+)\)$/;
@@ -17,7 +20,7 @@ export class FileOperations {
 		private readonly database: Database,
 		fs: FileSystemOperations
 	) {
-		this.fs = new SafeFileSystemOperations(fs);
+		this.fs = new SafeFileSystemOperations(fs, logger);
 	}
 
 	public async listAllFiles(): Promise<RelativePath[]> {
@@ -58,15 +61,37 @@ export class FileOperations {
 	// All parent directories are created if they don't exist.
 	public async create(
 		path: RelativePath,
-		newContent: Uint8Array
+		newContent: Uint8Array,
+		documentId?: DocumentId
 	): Promise<void> {
+		this.logger.debug(`Creating file: ${path}`);
 		if (await this.fs.exists(path)) {
 			const deconflictedPath = await this.deconflictPath(path);
 			this.logger.debug(
 				`Didn't expect ${path} to exist, deconflicting by moving it to '${deconflictedPath}'`
 			);
-			await this.database.updatePath(path, deconflictedPath);
-			await this.fs.rename(path, deconflictedPath);
+
+			const existingMetadata = this.database.getResolvedDocument(path);
+			this.logger.debug(
+				`Existing metadata for ${path}: ${JSON.stringify(existingMetadata)}`
+			);
+			if (
+				existingMetadata === undefined ||
+				existingMetadata.isDeleted ||
+				existingMetadata.documentId !== documentId ||
+				!documentId
+			) {
+				this.logger.debug(
+					`We need to save what's at ${path} to ${deconflictedPath}`
+				);
+				await this.move(path, deconflictedPath, documentId);
+				await this.database.move(path, deconflictedPath);
+			} else {
+				// This can happen if the document got moved both locally and remotely
+				// to the same file path. In this case, we shouldn't deconflict, however,
+				// we also can't overwrite otherwise we'd lose changes.
+				throw new FileNotFoundError(path);
+			}
 		} else {
 			await this.createParentDirectories(path);
 		}
@@ -126,9 +151,13 @@ export class FileOperations {
 		return new TextEncoder().encode(resultText);
 	}
 
-	public async remove(path: RelativePath): Promise<void> {
+	public async delete(path: RelativePath): Promise<void> {
+		if (!(await this.exists(path))) {
 			this.logger.debug(`Deleting file: ${path}`);
 			return this.fs.delete(path);
+		} else {
+			this.logger.debug(`No need to delete '${path}', it doesn't exist`);
+		}
 	}
 
 	public async move(
@@ -145,16 +174,20 @@ export class FileOperations {
 			this.logger.debug(
 				`Conflict when moving '${oldPath}' to '${newPath}', the latter already exists, deconflicting by moving it to '${deconflictedPath}'`
 			);
-
-			const existingMetadata = this.database.getDocument(newPath);
+			const existingMetadata = this.database.getResolvedDocument(newPath);
 			if (
 				existingMetadata === undefined ||
-				existingMetadata.documentId !== documentId
+				existingMetadata.isDeleted ||
+				existingMetadata.documentId !== documentId ||
+				!documentId
 			) {
-				await this.database.updatePath(newPath, deconflictedPath);
-				await this.fs.rename(newPath, deconflictedPath);
+				await this.move(newPath, deconflictedPath, documentId);
+				await this.database.move(oldPath, newPath);
 			} else {
-				await this.database.deleteDocument(newPath);
+				// This can happen if the document got moved both locally and remotely
+				// to the same file path. In this case, we shouldn't deconflict, however,
+				// we also can't overwrite otherwise we'd lose changes.
+				throw new FileNotFoundError(newPath);
 			}
 		} else {
 			await this.createParentDirectories(newPath);

frontend/sync-client/src/file-operations/filesystem-operations.ts

@@ -13,7 +13,5 @@ export interface FileSystemOperations {
 	exists: (path: RelativePath) => Promise<boolean>;
 	createDirectory: (path: RelativePath) => Promise<void>;
 	delete: (path: RelativePath) => Promise<void>;
-
-	// Must be able to handle renaming to a file that already exists
 	rename: (oldPath: RelativePath, newPath: RelativePath) => Promise<void>;
 }

frontend/sync-client/src/file-operations/safe-filesystem-operations.ts

@@ -1,5 +1,7 @@
-import type { RelativePath } from "src/persistence/database";
+import type { RelativePath } from "../persistence/database";
 import type { FileSystemOperations } from "./filesystem-operations";
+import type { Logger } from "../tracing/logger";
+import { DocumentLocks } from "./document-locks";
 
 export class FileNotFoundError extends Error {
 	public constructor(message: string) {
@@ -9,71 +11,145 @@ export class FileNotFoundError extends Error {
 }
 
 // Decorate FileSystemOperations replacing errors with FileNotFoundError
-// if the accessed file doesn't exist.
+// if the accessed file doesn't exist. It also ensures that there's only
+// ever a single request in-flight for any one file.
 export class SafeFileSystemOperations implements FileSystemOperations {
-	public constructor(private readonly fs: FileSystemOperations) {}
+	private readonly locks: DocumentLocks;
+
+	public constructor(
+		private readonly fs: FileSystemOperations,
+		private readonly logger: Logger
+	) {
+		this.locks = new DocumentLocks(logger);
+	}
 
 	public async listAllFiles(): Promise<RelativePath[]> {
+		this.logger.debug("Listing all files");
 		return this.fs.listAllFiles();
 	}
 
 	public async read(path: RelativePath): Promise<Uint8Array> {
-		return this.safeOperation(path, async () => this.fs.read(path));
+		this.logger.debug(`Reading file: ${path}`);
+		return this.safeOperation(
+			path,
+			this.decorateToHoldLock(path, async () => this.fs.read(path)),
+			"read"
+		);
 	}
 
 	public async write(path: RelativePath, content: Uint8Array): Promise<void> {
-		return this.fs.write(path, content);
+		this.logger.debug(`Writing file: ${path}`);
+		return this.decorateToHoldLock(path, async () =>
+			this.fs.write(path, content)
+		)();
 	}
 
 	public async atomicUpdateText(
 		path: RelativePath,
 		updater: (currentContent: string) => string
 	): Promise<string> {
-		return this.safeOperation(path, async () =>
+		this.logger.debug(`Atomic update of file: ${path}`);
+		return this.safeOperation(
+			path,
+			this.decorateToHoldLock(path, async () =>
 				this.fs.atomicUpdateText(path, updater)
+			),
+			"atomicUpdateText"
 		);
 	}
 
 	public async getFileSize(path: RelativePath): Promise<number> {
-		return this.safeOperation(path, async () => this.fs.getFileSize(path));
+		this.logger.debug(`Getting file size: ${path}`);
+		return this.safeOperation(
+			path,
+			this.decorateToHoldLock(path, async () =>
+				this.fs.getFileSize(path)
+			),
+			"getFileSize"
+		);
 	}
 
 	public async getModificationTime(path: RelativePath): Promise<Date> {
-		return this.safeOperation(path, async () =>
+		this.logger.debug(`Getting modification time: ${path}`);
+		return this.safeOperation(
+			path,
+			this.decorateToHoldLock(path, async () =>
 				this.fs.getModificationTime(path)
+			),
+			"getModificationTime"
 		);
 	}
 
 	public async exists(path: RelativePath): Promise<boolean> {
-		return this.fs.exists(path);
+		this.logger.debug(`Checking if file exists: ${path}`);
+		return this.decorateToHoldLock(path, async () =>
+			this.fs.exists(path)
+		)();
 	}
 
 	public async createDirectory(path: RelativePath): Promise<void> {
-		return this.fs.createDirectory(path);
+		this.logger.debug(`Creating directory: ${path}`);
+		return this.decorateToHoldLock(path, async () =>
+			this.fs.createDirectory(path)
+		)();
 	}
 
 	public async delete(path: RelativePath): Promise<void> {
-		return this.fs.delete(path);
+		this.logger.debug(`Deleting file: ${path}`);
+		return this.decorateToHoldLock(path, async () =>
+			this.fs.delete(path)
+		)();
 	}
 
 	public async rename(
 		oldPath: RelativePath,
 		newPath: RelativePath
 	): Promise<void> {
-		return this.safeOperation(oldPath, async () =>
+		this.logger.debug(`Renaming file: ${oldPath} to ${newPath}`);
+		return this.safeOperation(
+			oldPath,
+			this.decorateToHoldLock([oldPath, newPath], async () =>
 				this.fs.rename(oldPath, newPath)
+			),
+			"rename"
 		);
 	}
 
+	private decorateToHoldLock<T>(
+		pathOrPaths: RelativePath | RelativePath[],
+		operation: () => Promise<T>
+	): () => Promise<T> {
+		return async () => {
+			const paths = Array.isArray(pathOrPaths)
+				? pathOrPaths
+				: [pathOrPaths];
+			await Promise.all(
+				paths.map(async (path) => this.locks.waitForDocumentLock(path))
+			);
+			try {
+				return await operation();
+			} finally {
+				await Promise.all(
+					paths.map((path) => {
+						this.locks.unlockDocument(path);
+					})
+				);
+			}
+		};
+	}
+
 	private async safeOperation<T>(
 		path: RelativePath,
-		operation: () => Promise<T>
+		operation: () => Promise<T>,
+		operationName: string
 	): Promise<T> {
 		// Without locking the file, this isn't atomic, however, it's good enough practicaly.
 		// This will only break if the file exists, gets deleted and then immediately
 		// recreated while `operation` is running.
 		if (!(await this.fs.exists(path))) {
-			throw new FileNotFoundError(path);
+			throw new FileNotFoundError(
+				`File not found: ${path} before trying to ${operationName}`
+			);
 		}
 		try {
 			return await operation();
@@ -81,7 +157,9 @@ export class SafeFileSystemOperations implements FileSystemOperations {
 			if (await this.fs.exists(path)) {
 				throw error;
 			} else {
-				throw new FileNotFoundError(path);
+				throw new FileNotFoundError(
+					`File not found: ${path} when trying to ${operationName}`
+				);
 			}
 		}
 	}

frontend/sync-client/src/persistence/database.ts

@@ -6,6 +6,7 @@ export interface DocumentMetadata {
 	parentVersionId: VaultUpdateId;
 	documentId: DocumentId;
 	hash: string;
+	isDeleted: boolean;
 }
 
 import type { Logger } from "src/tracing/logger";
@@ -16,7 +17,10 @@ export interface StoredDatabase {
 }
 
 export class Database {
-	private documents = new Map<RelativePath, DocumentMetadata>();
+	private documents = new Map<
+		RelativePath,
+		DocumentMetadata | Promise<DocumentMetadata | undefined>
+	>();
 
 	private lastSeenUpdateId: VaultUpdateId | undefined;
 
@@ -43,8 +47,15 @@ export class Database {
 		);
 	}
 
-	public getDocuments(): Map<RelativePath, DocumentMetadata> {
-		return this.documents;
+	public get length(): number {
+		return this.documents.size;
+	}
+
+	public get resolvedDocuments(): [RelativePath, DocumentMetadata][] {
+		// eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
+		return Array.from(this.documents.entries()).filter(
+			([_, metadata]) => !(metadata instanceof Promise)
+		) as [RelativePath, DocumentMetadata][];
 	}
 
 	public getLastSeenUpdateId(): VaultUpdateId | undefined {
@@ -67,58 +78,106 @@ export class Database {
 	public getDocumentByDocumentId(
 		documentId: DocumentId
 	): [RelativePath, DocumentMetadata] | undefined {
-		return [...this.documents.entries()].find(
+		return this.resolvedDocuments.find(
 			([_, metadata]) => metadata.documentId === documentId
 		);
 	}
 
+	public getDocumentByIdentity(
+		document:
+			| DocumentMetadata
+			| Promise<DocumentMetadata | undefined>
+			| undefined
+	):
+		| [
+				RelativePath,
+				DocumentMetadata | Promise<DocumentMetadata | undefined>
+		  ]
+		| undefined {
+		if (document === undefined) {
+			return undefined;
+		}
+
+		return Array.from(this.documents.entries()).find(
+			([_, metadata]) => metadata === document
+		);
+	}
+
 	public async setDocument({
 		documentId,
 		relativePath,
 		parentVersionId,
-		hash
+		hash,
+		isDeleted
 	}: {
 		documentId: DocumentId;
 		relativePath: RelativePath;
 		parentVersionId: VaultUpdateId;
 		hash: string;
+		isDeleted: boolean;
 	}): Promise<void> {
 		this.documents.set(relativePath, {
 			documentId,
 			parentVersionId,
-			hash
+			hash,
+			isDeleted
 		});
 		await this.save();
 	}
 
-	public async removeDocument(relativePath: RelativePath): Promise<void> {
-		this.documents.delete(relativePath);
-		await this.save();
+	public async setDocumentPromise({
+		relativePath,
+		promise
+	}: {
+		relativePath: RelativePath;
+		promise: Promise<DocumentMetadata | undefined>;
+	}): Promise<void> {
+		this.documents.set(relativePath, promise);
+		// No need to save as Promises don't get serialized
+		// and a crash would only result in the document being
+		// creatied again.
+	}
+
+	public getResolvedDocument(
+		relativePath: RelativePath | undefined
+	): DocumentMetadata | undefined {
+		if (relativePath == undefined) {
+			return undefined;
+		}
+
+		const metadata = this.documents.get(relativePath);
+		if (metadata instanceof Promise) {
+			return undefined;
+		}
+
+		return metadata;
 	}
 
 	public getDocument(
-		relativePath: RelativePath
-	): DocumentMetadata | undefined {
+		relativePath: RelativePath | undefined
+	): Promise<DocumentMetadata | undefined> | DocumentMetadata | undefined {
+		if (relativePath == undefined) {
+			return undefined;
+		}
+
 		return this.documents.get(relativePath);
 	}
 
-	public async deleteDocument(relativePath: RelativePath): Promise<void> {
-		this.documents.delete(relativePath);
-		await this.save();
-	}
-
-	public async updatePath(
+	public async move(
 		oldRelativePath: RelativePath,
 		newRelativePath: RelativePath
 	): Promise<void> {
 		const document = this.documents.get(oldRelativePath);
 		if (!document) {
-			throw new Error(
-				`Cannot update physical path for document that does not exist: ${oldRelativePath}`
-			);
+			return;
 		}
 
-		if (this.documents.has(newRelativePath)) {
+		const resolvedDocument = this.getResolvedDocument(oldRelativePath);
+		if (
+			this.documents.has(newRelativePath) &&
+			resolvedDocument != undefined &&
+			resolvedDocument.isDeleted
+		) {
 			throw new Error(
 				`Cannot update physical path to path that is already in use: ${newRelativePath}`
 			);
@@ -133,16 +192,15 @@ export class Database {
 	private async save(): Promise<void> {
 		this.ensureConsistency();
 		await this.saveData({
-			documents: Object.fromEntries(this.documents.entries()),
+			documents: Object.fromEntries(this.resolvedDocuments),
 			lastSeenUpdateId: this.lastSeenUpdateId
 		});
 	}
 
 	private ensureConsistency(): void {
-		const allMetadata = Array.from(this.documents.entries());
-		const idToPath = new Map<string, Array<string>>();
+		const idToPath = new Map<string, string[]>();
 
-		allMetadata.forEach(([name, metadata]) => {
+		this.resolvedDocuments.forEach(([name, metadata]) => {
 			idToPath.set(metadata.documentId, [
 				...(idToPath.get(metadata.documentId) ?? []),
 				name

frontend/sync-client/src/services/sync-service.ts

@@ -59,7 +59,7 @@ export class SyncService {
 		relativePath: RelativePath;
 		contentBytes: Uint8Array;
 		createdDate: Date;
-	}): Promise<components["schemas"]["DocumentUpdateResponse"]> {
+	}): Promise<components["schemas"]["DocumentVersionWithoutContent"]> {
 		const formData = new FormData();
 		formData.append("relative_path", relativePath);
 		formData.append("created_date", createdDate.toISOString());
@@ -155,7 +155,7 @@ export class SyncService {
 		documentId: DocumentId;
 		relativePath: RelativePath;
 		createdDate: Date;
-	}): Promise<void> {
+	}): Promise<components["schemas"]["DocumentVersionWithoutContent"]> {
 		const response = await this.client.DELETE(
 			"/vaults/{vault_id}/documents/{document_id}",
 			{

frontend/sync-client/src/services/types.ts

@@ -274,12 +274,13 @@ export interface paths {
                 };
             };
             responses: {
-				/** @description no content */
                 200: {
                     headers: {
                         [name: string]: unknown;
                     };
-					content?: never;
+                    content: {
+                        "application/json": components["schemas"]["DocumentVersionWithoutContent"];
+                    };
                 };
                 default: {
                     headers: {
@@ -466,9 +467,8 @@ export interface components {
             createdDate: string;
             relativePath: string;
         };
-		/** @description Response to a update document request. */
-		DocumentUpdateResponse:
-			| {
+        /** @description Response to an update document request. */
+        DocumentUpdateResponse: {
             /** Format: date-time */
             createdDate: string;
             /** Format: uuid */
@@ -482,8 +482,7 @@ export interface components {
             vaultId: string;
             /** Format: int64 */
             vaultUpdateId: number;
-			  }
-			| {
+        } | {
             contentBase64: string;
             /** Format: date-time */
             createdDate: string;

frontend/sync-client/src/sync-client.ts

@@ -42,7 +42,7 @@ export class SyncClient {
 	}
 
 	public get documentCount(): number {
-		return this._database.getDocuments().size;
+		return this._database.length;
 	}
 
 	public set fetchImplementation(fetch: typeof globalThis.fetch) {

frontend/sync-client/src/sync-operations/syncer.ts

@@ -1,4 +1,8 @@
-import type { Database, RelativePath } from "../persistence/database";
+import type {
+	Database,
+	DocumentMetadata,
+	RelativePath
+} from "../persistence/database";
 
 import type { SyncService } from "src/services/sync-service";
 import type { Logger } from "src/tracing/logger";
@@ -10,6 +14,7 @@ import type { Settings } from "src/persistence/settings";
 import type { FileOperations } from "src/file-operations/file-operations";
 import { findMatchingFileBasedOnHash } from "src/utils/find-matching-file-based-on-hash";
 import { UnrestrictedSyncer } from "./unrestricted-syncer";
+import { FileNotFoundError } from "src/file-operations/safe-filesystem-operations";
 
 export class Syncer {
 	private readonly remainingOperationsListeners: ((
@@ -58,6 +63,23 @@ export class Syncer {
 		);
 	}
 
+	private static async forgivingFileNotFoundWrapper<T>(
+		fn: () => Promise<T>,
+		logger: Logger
+	): Promise<T | undefined> {
+		try {
+			return await fn();
+		} catch (e) {
+			if (e instanceof FileNotFoundError) {
+				logger.debug(
+					`File has been deleted or moved before we had a chance to inspect it, skipping`
+				);
+			} else {
+				throw e;
+			}
+		}
+	}
+
 	public addRemainingOperationsListener(
 		listener: (remainingOperations: number) => void
 	): void {
@@ -68,12 +90,44 @@ export class Syncer {
 		relativePath: RelativePath,
 		updateTime: Date
 	): Promise<void> {
-		await this.syncQueue.add(async () =>
-			this.internalSyncer.unrestrictedSyncLocallyCreatedFile(
+		let resolve:
+			| undefined
+			| ((metadata: DocumentMetadata | undefined) => void) = undefined;
+
+		const creationPromise = new Promise<DocumentMetadata | undefined>(
+			(r) => (resolve = r)
+		);
+
+		await this.database.setDocumentPromise({
+			relativePath,
+			promise: creationPromise
+		});
+
+		await this.syncQueue.add(async () => {
+			// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+			resolve!(
+				await this.internalSyncer.unrestrictedSyncLocallyCreatedFile(
 					relativePath,
 					updateTime
 				)
 			);
+		});
+	}
+
+	public async syncLocallyDeletedFile(
+		relativePath: RelativePath
+	): Promise<void> {
+		let metadata = this.database.getDocument(relativePath);
+		if (metadata !== undefined && !(metadata instanceof Promise)) {
+			metadata = Promise.resolve(metadata);
+		}
+
+		await this.syncQueue.add(async () =>
+			this.internalSyncer.unrestrictedSyncLocallyDeletedFile(
+				relativePath,
+				metadata
+			)
+		);
 	}
 
 	public async syncLocallyUpdatedFile(args: {
@@ -81,8 +135,25 @@ export class Syncer {
 		relativePath: RelativePath;
 		updateTime: Date;
 	}): Promise<void> {
+		if (args.oldPath === args.relativePath) {
+			throw new Error(
+				`Old path and new path are the same: ${args.oldPath}`
+			);
+		}
+
+		if (args.oldPath !== undefined) {
+			await this.database.move(args.oldPath, args.relativePath);
+		}
+
+		let metadata = this.database.getDocument(args.relativePath);
+		if (metadata !== undefined && !(metadata instanceof Promise)) {
+			metadata = Promise.resolve(metadata);
+		}
 		await this.syncQueue.add(async () =>
-			this.internalSyncer.unrestrictedSyncLocallyUpdatedFile(args)
+			this.internalSyncer.unrestrictedSyncLocallyUpdatedFile({
+				...args,
+				metadata
+			})
 		);
 	}
 
@@ -90,14 +161,6 @@ export class Syncer {
 		return this.syncQueue.onEmpty();
 	}
 
-	public async syncLocallyDeletedFile(
-		relativePath: RelativePath
-	): Promise<void> {
-		await this.syncQueue.add(async () =>
-			this.internalSyncer.unrestrictedSyncLocallyDeletedFile(relativePath)
-		);
-	}
-
 	public async scheduleSyncForOfflineChanges(): Promise<void> {
 		if (!this.settings.getSettings().isSyncEnabled) {
 			this.logger.debug(
@@ -178,32 +241,50 @@ export class Syncer {
 
 		// This includes renamed files for now
 		let locallyPossiblyDeletedFiles = [
-			...this.database.getDocuments().entries()
+			...this.database.resolvedDocuments
 		].filter(([path, _]) => !allLocalFiles.includes(path));
 
-		await Promise.all(
+		const updates = Promise.all(
 			allLocalFiles.map(async (relativePath) =>
 				this.syncQueue.add(async () => {
-					const metadata = this.database.getDocument(relativePath);
+					const metadata =
+						this.database.getResolvedDocument(relativePath);
 
 					if (metadata) {
 						this.logger.debug(
 							`Document ${relativePath} might have been updated locally, scheduling sync to validate and update it`
 						);
+						const updateTime =
+							await Syncer.forgivingFileNotFoundWrapper(
+								async () =>
+									this.operations.getModificationTime(
+										relativePath
+									),
+								this.logger
+							);
+						if (updateTime === undefined) {
+							return;
+						}
+
 						return this.internalSyncer.unrestrictedSyncLocallyUpdatedFile(
 							{
 								relativePath,
-								updateTime:
-									await this.operations.getModificationTime(
-										relativePath
-									)
+								updateTime,
+								metadata: Promise.resolve(metadata)
 							}
 						);
 					}
 
 					// Perhaps the file has been moved. Let's check by looking at the deleted files
 					const contentBytes =
-						await this.operations.read(relativePath);
+						await Syncer.forgivingFileNotFoundWrapper(
+							async () => this.operations.read(relativePath),
+							this.logger
+						);
+					if (contentBytes === undefined) {
+						return;
+					}
+
 					const contentHash = hash(contentBytes);
 
 					// todo: make this smarter so that offline files can be renamed & edited at the same time
@@ -221,13 +302,28 @@ export class Syncer {
 						this.logger.debug(
 							`Document '${originalFile[0]}' was not found under its current path in the database but was found under a different path (${relativePath}), scheduling sync to move it`
 						);
+
+						const updateTime =
+							await Syncer.forgivingFileNotFoundWrapper(
+								async () =>
+									this.operations.getModificationTime(
+										relativePath
+									),
+								this.logger
+							);
+						if (updateTime === undefined) {
+							return;
+						}
+
 						return this.internalSyncer.unrestrictedSyncLocallyUpdatedFile(
 							{
 								oldPath: originalFile[0],
-								relativePath: relativePath,
-								updateTime:
-									await this.operations.getModificationTime(
+								relativePath,
+								updateTime,
+								metadata: Promise.resolve(
+									this.database.getResolvedDocument(
 										relativePath
+									)
 								),
 								optimisations: {
 									contentBytes,
@@ -240,15 +336,26 @@ export class Syncer {
 					this.logger.debug(
 						`Document ${relativePath} not found in database, scheduling sync to create it`
 					);
+					const updateTime =
+						await Syncer.forgivingFileNotFoundWrapper(
+							async () =>
+								this.operations.getModificationTime(
+									relativePath
+								),
+							this.logger
+						);
+					if (updateTime === undefined) {
+						return;
+					}
 					return this.internalSyncer.unrestrictedSyncLocallyCreatedFile(
 						relativePath,
-						await this.operations.getModificationTime(relativePath)
+						updateTime
 					);
 				})
 			)
 		);
 
-		await Promise.all(
+		const deletes = Promise.all(
 			locallyPossiblyDeletedFiles.map(async ([relativePath, _]) => {
 				this.logger.debug(
 					`Document ${relativePath} has been deleted locally, scheduling sync to delete it`
@@ -265,6 +372,8 @@ export class Syncer {
 				return this.syncLocallyDeletedFile(relativePath);
 			})
 		);
+
+		await Promise.all([updates, deletes]);
 	}
 
 	private async internalApplyRemoteChangesLocally(): Promise<void> {
@@ -280,9 +389,15 @@ export class Syncer {
 		this.logger.info("Applying remote changes locally");
 
 		await Promise.all(
-			remote.latestDocuments.map(async (remoteDocument) =>
-				this.syncRemotelyUpdatedFile(remoteDocument)
+			remote.latestDocuments
+				.filter(
+					(remoteDocument) =>
+						remoteDocument.vaultUpdateId >
+						(this.database.getDocumentByDocumentId(
+							remoteDocument.documentId
+						)?.[1].parentVersionId ?? -1)
 				)
+				.map(this.syncRemotelyUpdatedFile.bind(this))
 		);
 
 		const lastSeenUpdateId = this.database.getLastSeenUpdateId();

frontend/sync-client/src/sync-operations/unrestricted-syncer.ts

@@ -1,19 +1,23 @@
-import type { Database, RelativePath } from "../persistence/database";
+import type {
+	Database,
+	DocumentMetadata,
+	RelativePath
+} from "../persistence/database";
 
 import type { SyncService } from "src/services/sync-service";
 import type { Logger } from "src/tracing/logger";
 import type { SyncHistory } from "src/tracing/sync-history";
 import { SyncSource, SyncStatus, SyncType } from "src/tracing/sync-history";
-import { hash } from "src/utils/hash";
+import { EMPTY_HASH, hash } from "src/utils/hash";
 import type { components } from "src/services/types";
 import { deserialize } from "src/utils/deserialize";
 import type { Settings } from "src/persistence/settings";
 import type { FileOperations } from "src/file-operations/file-operations";
 import { FileNotFoundError } from "src/file-operations/safe-filesystem-operations";
-import { DocumentLocks } from "./document-locks";
+import { DocumentLocks } from "../file-operations/document-locks";
 
 export class UnrestrictedSyncer {
-	private readonly locks = new DocumentLocks();
+	private readonly locks: DocumentLocks;
 
 	public constructor(
 		private readonly logger: Logger,
@@ -22,7 +26,9 @@ export class UnrestrictedSyncer {
 		private readonly syncService: SyncService,
 		private readonly operations: FileOperations,
 		private readonly history: SyncHistory
-	) {}
+	) {
+		this.locks = new DocumentLocks(logger);
+	}
 
 	public async unrestrictedSyncLocallyCreatedFile(
 		relativePath: RelativePath,
@@ -31,96 +37,132 @@ export class UnrestrictedSyncer {
 			contentBytes?: Uint8Array;
 			contentHash?: string;
 		}
-	): Promise<void> {
-		await this.executeWhileHoldingFileLock(
+	): Promise<DocumentMetadata | undefined> {
+		return this.executeSync(
 			[relativePath],
 			SyncType.CREATE,
 			SyncSource.PUSH,
 			async () => {
+				const localMetadata = this.database.getDocument(relativePath);
+
 				if (
-					(await this.operations.getFileSize(relativePath)) / // this can throw FileNotFoundError
-						1024 /
-						1024 >
-					this.settings.getSettings().maxFileSizeMB
+					!(localMetadata instanceof Promise) &&
+					localMetadata &&
+					!localMetadata.isDeleted
 				) {
-					this.history.addHistoryEntry({
-						status: SyncStatus.ERROR,
-						relativePath,
-						message: `File size exceeds the maximum file size limit of ${
-							this.settings.getSettings().maxFileSizeMB
-						}MB`,
-						type: SyncType.CREATE
-					});
+					this.logger.debug(
+						`Document metadata already exists for ${relativePath}, it must have been downloaded from the server`
+					);
+
 					return;
 				}
 
 				const contentBytes =
 					optimisations?.contentBytes ??
 					(await this.operations.read(relativePath)); // this can throw FileNotFoundError
-				let contentHash =
+				const contentHash =
 					optimisations?.contentHash ?? hash(contentBytes);
 
-				const localMetadata = this.database.getDocument(relativePath);
-				if (localMetadata) {
-					this.logger.debug(
-						`Document metadata already exists for ${relativePath}, it must have been downloaded from the server`
-					);
-
-					if (localMetadata.hash === contentHash) {
-						this.history.addHistoryEntry({
-							status: SyncStatus.NO_OP,
-							relativePath,
-							message: `File hash matches with last synced version, no need to sync`,
-							type: SyncType.UPDATE
-						});
-						return;
-					}
-				}
-
 				const response = await this.syncService.create({
 					relativePath,
 					contentBytes,
 					createdDate: updateTime
 				});
 
+				const currentMetadata =
+					this.database.getDocumentByIdentity(localMetadata);
+				if (!currentMetadata) {
+					throw new Error(
+						`Document metadata for ${relativePath} not found after creation`
+					);
+				}
+
 				this.history.addHistoryEntry({
 					status: SyncStatus.SUCCESS,
 					source: SyncSource.PUSH,
-					relativePath,
+					relativePath: currentMetadata[0],
 					message: `Successfully uploaded locally created file`,
 					type: SyncType.CREATE
 				});
 
-				// The response can't have a different relative path than the one we sent
-				// because the relative path is the key when finding existing documents
-				// when a create request is sent.
-
-				if (response.type === "MergingUpdate") {
-					const responseBytes = deserialize(response.contentBase64);
-					contentHash = hash(responseBytes);
-
-					await this.operations.write(
-						relativePath,
-						contentBytes,
-						responseBytes
-					);
-					this.history.addHistoryEntry({
-						status: SyncStatus.SUCCESS,
-						source: SyncSource.PULL,
-						relativePath,
-						message: `The file we created locally has already existed remotely, so we have merged them`,
-						type: SyncType.UPDATE
-					});
-				}
+				const newMetadata = {
+					documentId: response.documentId,
+					parentVersionId: response.vaultUpdateId,
+					hash: contentHash,
+					isDeleted: false
+				};
 
 				await this.database.setDocument({
-					documentId: response.documentId,
-					relativePath: response.relativePath,
-					parentVersionId: response.vaultUpdateId,
-					hash: contentHash
+					relativePath: currentMetadata[0],
+					...newMetadata
 				});
 
 				await this.tryIncrementVaultUpdateId(response.vaultUpdateId);
+
+				return newMetadata;
+			}
+		);
+	}
+
+	public async unrestrictedSyncLocallyDeletedFile(
+		relativePath: RelativePath,
+		metadata: Promise<DocumentMetadata | undefined> | undefined
+	): Promise<void> {
+		await this.executeSync(
+			[relativePath],
+			SyncType.DELETE,
+			SyncSource.PUSH,
+			async () => {
+				const localMetadata =
+					metadata !== undefined
+						? await metadata
+						: this.database.getResolvedDocument(relativePath);
+
+				if (!localMetadata || localMetadata.isDeleted) {
+					this.logger.info(
+						`Locally deleted file hasn't been uploaded yet, so there's no need to delete it on the remote server`
+					);
+
+					return;
+				}
+
+				const response = await this.syncService.delete({
+					documentId: localMetadata.documentId,
+					relativePath,
+					createdDate: new Date() // We got the event now, so it must have been deleted just now
+				});
+
+				this.history.addHistoryEntry({
+					status: SyncStatus.SUCCESS,
+					source: SyncSource.PUSH,
+					relativePath,
+					message: `Successfully deleted locally deleted file on the remote server`,
+					type: SyncType.DELETE
+				});
+
+				const currentMetadata = this.database.getDocumentByDocumentId(
+					localMetadata.documentId
+				);
+
+				if (!currentMetadata || currentMetadata[1].isDeleted) {
+					this.logger.info(
+						`No metadata found for deleted file, '${relativePath}' must have been deleted by another operation`
+					);
+
+					return;
+				}
+
+				await this.operations.delete(currentMetadata[0]);
+
+				// We have to have a record of the delete in case there's an in-flight update for the same
+				// document which finishes after the delete has succeeded and would introduce a phantom metadata record.
+				await this.database.setDocument({
+					relativePath: currentMetadata[0],
+					documentId: response.documentId,
+					parentVersionId: response.vaultUpdateId,
+					hash: EMPTY_HASH,
+					isDeleted: true
+				});
 			}
 		);
 	}
@@ -128,53 +170,34 @@ export class UnrestrictedSyncer {
 	public async unrestrictedSyncLocallyUpdatedFile({
 		oldPath,
 		relativePath,
+		metadata,
 		updateTime,
 		optimisations
 	}: {
 		oldPath?: RelativePath;
 		relativePath: RelativePath;
+		metadata: Promise<DocumentMetadata | undefined> | undefined;
 		updateTime: Date;
 		optimisations?: {
 			contentBytes?: Uint8Array;
 			contentHash?: string;
 		};
 	}): Promise<void> {
-		await this.executeWhileHoldingFileLock(
+		await this.executeSync(
 			[oldPath, relativePath].filter((path) => path !== undefined),
 			SyncType.UPDATE,
 			SyncSource.PUSH,
 			async () => {
-				// Check the new path first in case the metadata has been already moved
-				let localMetadata = this.database.getDocument(relativePath);
-				let metadataPath = relativePath;
+				const localMetadata =
+					metadata !== undefined
+						? await metadata
+						: this.database.getResolvedDocument(relativePath);
 
-				if (localMetadata === undefined && oldPath !== undefined) {
-					localMetadata = this.database.getDocument(oldPath);
-					metadataPath = oldPath;
-				}
-
-				if (!localMetadata) {
+				if (!localMetadata || localMetadata.isDeleted) {
 					// It's fine, a subsequent sync operation must have dealt with this
 					return;
 				}
 
-				if (
-					(await this.operations.getFileSize(relativePath)) / // this can throw FileNotFoundError
-						1024 /
-						1024 >
-					this.settings.getSettings().maxFileSizeMB
-				) {
-					this.history.addHistoryEntry({
-						status: SyncStatus.ERROR,
-						relativePath,
-						message: `File size exceeds the maximum file size limit of ${
-							this.settings.getSettings().maxFileSizeMB
-						}MB`,
-						type: SyncType.CREATE
-					});
-					return;
-				}
-
 				const contentBytes =
 					optimisations?.contentBytes ??
 					(await this.operations.read(relativePath)); // this can throw FileNotFoundError
@@ -186,23 +209,48 @@ export class UnrestrictedSyncer {
 					localMetadata.hash === contentHash &&
 					oldPath === undefined
 				) {
-					this.history.addHistoryEntry({
-						status: SyncStatus.NO_OP,
-						relativePath,
-						message: `File hash matches with last synced version, no need to sync`,
-						type: SyncType.UPDATE
-					});
+					this.logger.debug(
+						`File hash of ${relativePath} matches with last synced version and the path hasn't changed; no need to sync`
+					);
+					return;
+				}
+
+				// Re-fetch based on the documentId instead of the relativePath because
+				// the relativePath might have changed since this operation was scheduled
+				let latestMetadata = this.database.getDocumentByDocumentId(
+					localMetadata.documentId
+				);
+				if (!latestMetadata || latestMetadata[1].isDeleted) {
+					// It's fine, a subsequent sync operation must have dealt with this
 					return;
 				}
 
 				const response = await this.syncService.put({
-					documentId: localMetadata.documentId,
-					parentVersionId: localMetadata.parentVersionId,
-					relativePath,
+					documentId: latestMetadata[1].documentId,
+					parentVersionId: latestMetadata[1].parentVersionId,
+					relativePath: latestMetadata[0],
 					contentBytes,
 					createdDate: updateTime
 				});
 
+				latestMetadata = this.database.getDocumentByDocumentId(
+					response.documentId
+				);
+
+				if (!latestMetadata || latestMetadata[1].isDeleted) {
+					// The document has been deleted since this operation was scheduled
+					return;
+				}
+
+				if (
+					latestMetadata[1].parentVersionId >= response.vaultUpdateId
+				) {
+					this.logger.debug(
+						`Document ${relativePath} is already more up to date than the fetched version`
+					);
+					return;
+				}
+
 				this.history.addHistoryEntry({
 					status: SyncStatus.SUCCESS,
 					source: SyncSource.PUSH,
@@ -212,11 +260,7 @@ export class UnrestrictedSyncer {
 				});
 
 				if (response.isDeleted) {
-					await this.operations.remove(oldPath ?? relativePath);
-					await this.database.removeDocument(oldPath ?? relativePath);
-					await this.tryIncrementVaultUpdateId(
-						response.vaultUpdateId
-					);
+					await this.operations.delete(relativePath);
 
 					this.history.addHistoryEntry({
 						status: SyncStatus.SUCCESS,
@@ -227,31 +271,40 @@ export class UnrestrictedSyncer {
 						type: SyncType.DELETE
 					});
 
+					await this.database.setDocument({
+						documentId: response.documentId,
+						relativePath: latestMetadata[0],
+						parentVersionId: response.vaultUpdateId,
+						hash: EMPTY_HASH,
+						isDeleted: true
+					});
+
+					await this.tryIncrementVaultUpdateId(
+						response.vaultUpdateId
+					);
+
 					return;
 				}
 
 				if (
-					response.relativePath != relativePath &&
-					response.relativePath != oldPath
+					latestMetadata[1].parentVersionId >= response.vaultUpdateId
 				) {
-					await this.locks.waitForDocumentLock(response.relativePath);
+					this.logger.debug(
+						`Document ${relativePath} is already more up to date than the fetched version`
+					);
+					return;
 				}
 
-				try {
 				if (response.relativePath != relativePath) {
-						// TODO: this can fail, that's bad
 					await this.operations.move(
-							// this can throw FileNotFoundError
-							relativePath,
+						latestMetadata[0],
 						response.relativePath,
 						response.documentId
-						);
+					); // this can throw FileNotFoundError
 				}
 
 				if (response.type === "MergingUpdate") {
-						const responseBytes = deserialize(
-							response.contentBase64
-						);
+					const responseBytes = deserialize(response.contentBase64);
 					contentHash = hash(responseBytes);
 
 					await this.operations.write(
@@ -269,68 +322,18 @@ export class UnrestrictedSyncer {
 					});
 				}
 
-					if (metadataPath !== response.relativePath) {
-						await this.database.updatePath(
-							metadataPath,
-							response.relativePath
-						);
-					}
 				await this.database.setDocument({
-						documentId: localMetadata.documentId,
-						relativePath: response.relativePath,
+					documentId: response.documentId,
+					relativePath:
+						response.relativePath != relativePath
+							? response.relativePath
+							: latestMetadata[0],
 					parentVersionId: response.vaultUpdateId,
-						hash: contentHash
+					hash: contentHash,
+					isDeleted: response.isDeleted
 				});
 
-					await this.tryIncrementVaultUpdateId(
-						response.vaultUpdateId
-					);
-				} finally {
-					if (
-						response.relativePath != relativePath &&
-						response.relativePath != oldPath
-					) {
-						this.locks.unlockDocument(response.relativePath);
-					}
-				}
-			}
-		);
-	}
-
-	public async unrestrictedSyncLocallyDeletedFile(
-		relativePath: RelativePath
-	): Promise<void> {
-		await this.executeWhileHoldingFileLock(
-			[relativePath],
-			SyncType.DELETE,
-			SyncSource.PUSH,
-			async () => {
-				const localMetadata = this.database.getDocument(relativePath);
-				if (!localMetadata) {
-					this.history.addHistoryEntry({
-						status: SyncStatus.NO_OP,
-						relativePath,
-						message: `Locally deleted file hasn't been uploaded yet, so there's no need to delete it on the remote server`,
-						type: SyncType.DELETE
-					});
-					return;
-				}
-
-				await this.syncService.delete({
-					documentId: localMetadata.documentId,
-					relativePath,
-					createdDate: new Date() // We got the event now, so it must have been deleted just now
-				});
-
-				this.history.addHistoryEntry({
-					status: SyncStatus.SUCCESS,
-					source: SyncSource.PUSH,
-					relativePath,
-					message: `Successfully deleted locally deleted file on the remote server`,
-					type: SyncType.DELETE
-				});
-
-				await this.database.removeDocument(relativePath);
+				await this.tryIncrementVaultUpdateId(response.vaultUpdateId);
 			}
 		);
 	}
@@ -338,56 +341,68 @@ export class UnrestrictedSyncer {
 	public async unrestrictedSyncRemotelyUpdatedFile(
 		remoteVersion: components["schemas"]["DocumentVersionWithoutContent"]
 	): Promise<void> {
-		await this.executeWhileHoldingFileLock(
+		await this.executeSync(
 			[remoteVersion.relativePath],
 			SyncType.UPDATE,
 			SyncSource.PULL,
 			async () => {
-				let localMetadata = this.database.getDocumentByDocumentId(
-					remoteVersion.documentId
-				);
-
-				if (
-					localMetadata &&
-					localMetadata[0] !== remoteVersion.relativePath
-				) {
-					await this.locks.waitForDocumentLock(localMetadata[0]);
-				}
-				// Waiting for the new lock might take a while so we need to fetch the database
-				// entry again in case it's changed.
-				localMetadata = this.database.getDocumentByDocumentId(
-					remoteVersion.documentId
-				);
-
-				if (!localMetadata) {
-					if (remoteVersion.isDeleted) {
-						this.history.addHistoryEntry({
-							status: SyncStatus.NO_OP,
-							source: SyncSource.PULL,
-							relativePath: remoteVersion.relativePath,
-							message: `Remotely deleted file hasn't been synced yet, so there's no need to delete it locally`,
-							type: SyncType.DELETE
-						});
-						return;
-					}
-
 				const content = (
 					await this.syncService.get({
 						documentId: remoteVersion.documentId
 					})
 				).contentBase64;
 				const contentBytes = deserialize(content);
+				const contentHash = hash(contentBytes);
+
+				const localMetadata = this.database.getDocumentByDocumentId(
+					remoteVersion.documentId
+				);
+				if (
+					localMetadata?.[1].documentId ===
+						remoteVersion.documentId &&
+					localMetadata[1].parentVersionId >
+						remoteVersion.vaultUpdateId
+				) {
+					this.logger.info(
+						`Document ${remoteVersion.relativePath} is already up to date`
+					);
+					return;
+				}
+
+				const localBytes = await this.operations.read(
+					remoteVersion.relativePath
+				); // this can throw FileNotFoundError
+				const localHash = hash(localBytes);
+
+				if (localHash !== localMetadata?.[1].hash) {
+					this.logger.info(
+						`Document ${remoteVersion.relativePath} has pending local changes, so we shouldn't update it here`
+					);
+					return;
+				}
+
+				if (!localMetadata || localMetadata[1].isDeleted) {
+					if (remoteVersion.isDeleted) {
+						this.logger.info(
+							`Remotely deleted file hasn't been synced yet, so there's no need to delete it locally`
+						);
+						return;
+					}
 
 					await this.operations.create(
 						remoteVersion.relativePath,
-						contentBytes
+						contentBytes,
+						remoteVersion.documentId
 					);
+
 					await this.database.setDocument({
 						documentId: remoteVersion.documentId,
 						relativePath: remoteVersion.relativePath,
 						parentVersionId: remoteVersion.vaultUpdateId,
-						hash: hash(contentBytes)
+						hash: hash(contentBytes),
+						isDeleted: remoteVersion.isDeleted
 					});
+
 					this.history.addHistoryEntry({
 						status: SyncStatus.SUCCESS,
 						source: SyncSource.PULL,
@@ -399,7 +414,6 @@ export class UnrestrictedSyncer {
 				}
 
 				const [relativePath, metadata] = localMetadata;
-
 				if (remoteVersion.vaultUpdateId <= metadata.parentVersionId) {
 					this.logger.debug(
 						`Document ${relativePath} is already up to date`
@@ -407,10 +421,8 @@ export class UnrestrictedSyncer {
 					return;
 				}
 
-				try {
 				if (remoteVersion.isDeleted) {
-						await this.operations.remove(relativePath);
-						await this.database.removeDocument(relativePath);
+					await this.operations.delete(relativePath);
 
 					this.history.addHistoryEntry({
 						status: SyncStatus.SUCCESS,
@@ -419,27 +431,18 @@ export class UnrestrictedSyncer {
 						message: `Successfully deleted remotely deleted file locally`,
 						type: SyncType.DELETE
 					});
-					} else {
-						// TODO: this can fail, that's bad
-						const currentContent =
-							await this.operations.read(relativePath); // this can throw FileNotFoundError
-						const currentHash = hash(currentContent);
 
-						if (currentHash !== metadata.hash) {
-							this.logger.info(
-								`Document ${relativePath} has been updated both remotely and locally, letting the local file update event handle it`
-							);
+					await this.database.setDocument({
+						documentId: remoteVersion.documentId,
+						relativePath: relativePath,
+						parentVersionId: remoteVersion.vaultUpdateId,
+						hash: EMPTY_HASH,
+						isDeleted: true
+					});
+
 					return;
 				}
 
-						const content = (
-							await this.syncService.get({
-								documentId: remoteVersion.documentId
-							})
-						).contentBase64;
-						const contentBytes = deserialize(content);
-						const contentHash = hash(contentBytes);
-
 				if (relativePath !== remoteVersion.relativePath) {
 					// TODO: this can fail, that's bad
 					await this.operations.move(
@@ -448,23 +451,21 @@ export class UnrestrictedSyncer {
 						remoteVersion.relativePath,
 						remoteVersion.documentId
 					);
-
-							await this.database.updatePath(
-								relativePath,
-								remoteVersion.relativePath
-							);
 				}
 
-						await this.operations.write(
+				// todo: why
+				await this.operations.create(
 					remoteVersion.relativePath,
-							currentContent,
-							contentBytes
+					contentBytes,
+					remoteVersion.documentId
 				);
+
 				await this.database.setDocument({
 					documentId: remoteVersion.documentId,
 					relativePath: remoteVersion.relativePath,
 					parentVersionId: remoteVersion.vaultUpdateId,
-							hash: contentHash
+					hash: contentHash,
+					isDeleted: remoteVersion.isDeleted
 				});
 
 				this.history.addHistoryEntry({
@@ -475,21 +476,15 @@ export class UnrestrictedSyncer {
 					type: SyncType.UPDATE
 				});
 			}
-				} finally {
-					if (relativePath !== remoteVersion.relativePath) {
-						this.locks.unlockDocument(relativePath);
-					}
-				}
-			}
 		);
 	}
 
-	public async executeWhileHoldingFileLock(
+	public async executeSync<T>(
 		lockedPaths: RelativePath[],
 		syncType: SyncType,
 		syncSource: SyncSource,
-		fn: () => Promise<void>
-	): Promise<void> {
+		fn: () => Promise<T>
+	): Promise<T | undefined> {
 		const relativePath = lockedPaths[lockedPaths.length - 1];
 
 		if (!this.settings.getSettings().isSyncEnabled) {
@@ -498,31 +493,47 @@ export class UnrestrictedSyncer {
 			);
 			return;
 		}
+
 		if (!this.operations.isFileEligibleForSync(relativePath)) {
-			this.logger.info(
-				`File ${relativePath} is not eligible for syncing`
-			);
+			this.history.addHistoryEntry({
+				status: SyncStatus.ERROR,
+				relativePath,
+				message: `File ${relativePath} is not eligible for syncing`,
+				type: syncType
+			});
 			return;
 		}
+
 		this.logger.debug(
 			`Syncing ${relativePath} (${syncSource} - ${syncType})`
 		);
 
-		await Promise.all(
-			lockedPaths.map(this.locks.waitForDocumentLock.bind(this.locks))
-		);
 		try {
-			await fn();
+			if (
+				(await this.operations.exists(relativePath)) &&
+				(await this.operations.getFileSize(relativePath)) / // this can throw FileNotFoundError
+					1024 /
+					1024 >
+					this.settings.getSettings().maxFileSizeMB
+			) {
+				this.history.addHistoryEntry({
+					status: SyncStatus.ERROR,
+					relativePath,
+					message: `File size exceeds the maximum file size limit of ${
+						this.settings.getSettings().maxFileSizeMB
+					}MB`,
+					type: syncType
+				});
+				return;
+			}
+
+			return await fn();
 		} catch (e) {
 			if (e instanceof FileNotFoundError) {
 				// A subsequent sync operation must have been creating to deal with this
-				this.history.addHistoryEntry({
-					status: SyncStatus.NO_OP,
-					relativePath,
-					message: `Skip ${syncSource.toLocaleLowerCase()} file because it no longer exists when trying to ${syncType.toLocaleLowerCase()} it`,
-					type: syncType,
-					source: syncSource
-				});
+				this.logger.info(
+					`Skip ${syncSource.toLocaleLowerCase()} file because it no longer exists when trying to ${syncType.toLocaleLowerCase()} it`
+				);
 			} else {
 				this.history.addHistoryEntry({
 					status: SyncStatus.ERROR,
@@ -533,8 +544,6 @@ export class UnrestrictedSyncer {
 				});
 				throw e;
 			}
-		} finally {
-			lockedPaths.forEach(this.locks.unlockDocument.bind(this.locks));
 		}
 	}
 

frontend/test-client/src/agent/mock-agent.ts

@@ -46,27 +46,31 @@ export class MockAgent extends MockClient {
 				? "(online) "
 				: "(offline)";
 			const formatted = `[${this.name} ${state}] ${logLine.timestamp.toISOString()} ${logLine.level} ${logLine.message}`;
+
+			// HACK: we have to ensure the file has been synced if we want to change it offline without data loss
+			const historyEntry = /.*History entry: (.*.md).*/.exec(
+				logLine.message
+			);
+
+			if (historyEntry) {
+				this.doNotTouchWhileOffline =
+					this.doNotTouchWhileOffline.filter(
+						(file) => file !== historyEntry[1]
+					);
+			}
 			switch (logLine.level) {
 				case LogLevel.ERROR:
 					console.error(formatted);
+
 					// Let's not ignore errors
-					process.exit(1);
+					// eslint-disable-next-line @typescript-eslint/no-floating-promises
+					sleep(1000).then(() => process.exit(1));
+
 					break;
 				case LogLevel.WARNING:
 					console.warn(formatted);
 					break;
 				case LogLevel.INFO:
-					// HACK: we have to ensure the file has been synced if we want to change it offline without data loss
-					const result = /.*History entry: (.*.md).*/.exec(
-						logLine.message
-					);
-					if (result) {
-						this.doNotTouchWhileOffline =
-							this.doNotTouchWhileOffline.filter(
-								(file) => file !== result[1]
-							);
-					}
-
 					console.info(formatted);
 					break;
 				case LogLevel.DEBUG:
@@ -79,16 +83,17 @@ export class MockAgent extends MockClient {
 	}
 
 	public async act(): Promise<void> {
+		this.assertAllContentIsPresentOnce();
+
 		const options: (() => Promise<unknown>)[] = [
 			this.createFileAction.bind(this),
 			this.changeFetchChangesUpdateIntervalMsAction.bind(this)
 		];
 
-		if (
-			this.client.settings.getSettings().isSyncEnabled &&
-			this.doNotTouchWhileOffline.length === 0
-		) {
+		if (this.client.settings.getSettings().isSyncEnabled) {
+			if (this.doNotTouchWhileOffline.length === 0) {
 				options.push(this.disableSyncAction.bind(this));
+			}
 		} else {
 			options.push(this.enableSyncAction.bind(this));
 		}

frontend/test-client/src/cli.ts

@@ -38,6 +38,8 @@ async function runTest({
 			)
 		);
 	}
+	// for debugging
+	(globalThis as any).clients = clients;
 
 	try {
 		await Promise.all(clients.map(async (client) => client.init()));
@@ -78,26 +80,25 @@ async function runTest({
 			console.info(`Content check for ${client.name} passed`);
 		});
 
-		console.info(`Test passed with ${settings}`);
+		console.info(`Test passed ${settings}`);
 	} catch (err) {
-		console.error(`Test failed with ${settings}`);
+		console.error(`Test failed ${settings}`);
 		throw err;
 	}
 }
 
 async function runTests(): Promise<void> {
 	const agentCounts = [2, 10];
-	const jitterScaleInSeconds = [0.5, 3, 0];
+	const jitterScaleInSeconds = [0, 0.5, 3];
 	const concurrencies = [1, 16];
 	const iterations = [50, 300];
-	const doDeletes = [false, true];
+	const doDeletes = [false];
 
 	for (const agentCount of agentCounts) {
 		for (const concurrency of concurrencies) {
 			for (const jitter of jitterScaleInSeconds) {
 				for (const iteration of iterations) {
 					for (const deleteFiles of doDeletes) {
-						while (true) {
 						await runTest({
 							agentCount,
 							concurrency,
@@ -111,13 +112,25 @@ async function runTests(): Promise<void> {
 		}
 	}
 }
-}
+
+process.on("uncaughtException", async (error) => {
+	console.error("Uncaught Exception:", error);
+	await sleep(1000);
+	process.exit(1);
+});
+
+process.on("unhandledRejection", async (reason, promise) => {
+	console.error("Unhandled Rejection:", reason);
+	await sleep(1000);
+	process.exit(1);
+});
 
 runTests()
 	.then(() => {
 		process.exit(0);
 	})
-	.catch((err: unknown) => {
+	.catch(async (err: unknown) => {
 		console.error(err);
+		await sleep(1000);
 		process.exit(1);
 	});