Studio sync: handle 413 push failures gracefully

apps/studio/src/modules/sync/lib/ipc-handlers.ts

@@ -13,9 +13,11 @@ import {
 import { isErrnoException } from '@studio/common/lib/is-errno-exception';
 import { getCurrentUserId } from '@studio/common/lib/shared-config';
 import { fetchSyncableSites } from '@studio/common/lib/sync/sync-api';
+import { shouldRetryTusStatus } from '@studio/common/lib/sync/tus-upload';
 import wpcomFactory from '@studio/common/lib/wpcom-factory';
 import wpcomXhrRequest from '@studio/common/lib/wpcom-xhr-request-factory';
 import { SyncSite } from '@studio/common/types/sync';
+import { __, sprintf } from '@wordpress/i18n';
 import { Upload } from 'tus-js-client';
 import { z } from 'zod';
 import {
@@ -319,12 +321,7 @@ export async function pushArchive(
 				}
 
 				const status = error.originalResponse ? error.originalResponse.getStatus() : 0;
-				// Stop retrying if the upload failed because of a 403 error.
-				if ( status === 403 ) {
-					return false;
-				}
-
-				return true;
+				return shouldRetryTusStatus( status );
 			},
 		} );
 
@@ -388,8 +385,38 @@ export async function pushArchive(
 			return { success: false, error: parseResult.data.error };
 		}
 
-		return { success: false, error: 'Unknown error' };
+		// A bare upload failure (e.g. a 413) has no `{ error: string }` body, so
+		// fall back to the HTTP status for a meaningful message.
+		const status = getTusErrorStatus( error );
+		if ( status === 413 ) {
+			return {
+				success: false,
+				error: __( 'The site archive is too large to upload right now. Please try again later.' ),
+			};
+		}
+		if ( status ) {
+			return {
+				success: false,
+				// translators: %d is the HTTP status code of the failed upload, e.g. 500.
+				error: sprintf( __( 'Upload failed with HTTP status %d.' ), status ),
+			};
+		}
+
+		return { success: false, error: __( 'Unknown error' ) };
+	}
+}
+
+function getTusErrorStatus( error: unknown ): number {
+	if (
+		typeof error === 'object' &&
+		error !== null &&
+		'originalResponse' in error &&
+		error.originalResponse &&
+		typeof ( error.originalResponse as { getStatus?: unknown } ).getStatus === 'function'
+	) {
+		return ( error.originalResponse as { getStatus: () => number } ).getStatus();
 	}
+	return 0;
 }
 
 export async function downloadSyncBackup(

tools/common/lib/sync/tus-upload.ts

@@ -2,6 +2,17 @@ import fs from 'fs';
 import nodePath from 'path';
 import { Upload } from 'tus-js-client';
 
+/**
+ * 5xx and network errors (status 0) are transient. 4xx are terminal, except 409
+ * (Conflict) and 423 (Locked), which the resumable protocol uses transiently.
+ */
+export function shouldRetryTusStatus( status: number ): boolean {
+	if ( status >= 400 && status < 500 ) {
+		return status === 409 || status === 423;
+	}
+	return true;
+}
+
 export type TusUploadOptions = {
 	token: string;
 	remoteSiteId: number;
@@ -110,7 +121,7 @@ export function createTusUpload( options: TusUploadOptions ): {
 					}
 
 					const status = error.originalResponse ? error.originalResponse.getStatus() : 0;
-					return status !== 403;
+					return shouldRetryTusStatus( status );
 				},
 			} );