(core) Fix issue with sandboxUtil where %s in message would get interpreted wrongly

Summary:
- Also converted sandboxUtil to typescript.
- The issue with %s manifested when a Python traceback contained "%s" in the
  string; in that case the object with log metadata (e.g. docId) would
  confusingly replace %s as if it were part of the message from Python.

Test Plan: Added a test case for the fix.

Reviewers: alexmojaki

Reviewed By: alexmojaki

Differential Revision: https://phab.getgrist.com/D3486

app/server/lib/sandboxUtil.ts

@@ -1,26 +1,18 @@
 /**
  * Various utilities and constants for communicating with the python sandbox.
  */
-
+import * as MemBuffer from 'app/common/MemBuffer';
-
+import * as log from 'app/server/lib/log';
-var MemBuffer = require('app/common/MemBuffer');
-var log = require('./log');
 
 
 /**
  * SandboxError is an error type for reporting errors forwarded from the sandbox.
  */
-function SandboxError(message) {
+export class SandboxError extends Error {
-  // Poorly documented node feature, required to make the derived error keep a proper stack trace.
+  constructor(message: string) {
-  Error.captureStackTrace(this, this.constructor);
+    super("[Sandbox] " + (message || 'Python reported an error'));
-  this.name = 'SandboxError';
+  }
-  this.message = "[Sandbox] " + (message || 'Python reported an error');
 }
-SandboxError.prototype = new Error();
-// We need to set the .constructor property for Error.captureStackTrace to work correctly.
-SandboxError.prototype.constructor = SandboxError;
-
-exports.SandboxError = SandboxError;
 
 
 /**
@@ -30,9 +22,9 @@ exports.SandboxError = SandboxError;
  *    DATA = data must be a value to return to a call from the other side
  *    EXC = data must be an exception to return to a call from the other side
  */
-exports.CALL = null;
+export const CALL = null;
-exports.DATA = true;
+export const DATA = true;
-exports.EXC = false;
+export const EXC = false;
 
 
 /**
@@ -40,19 +32,18 @@ exports.EXC = false;
  * The logged output is line-oriented, so that the prefix is only inserted at the start of a line.
  * Binary data is encoded as with JSON.stringify.
  */
-function makeLinePrefixer(prefix, logMeta) {
+export function makeLinePrefixer(prefix: string, logMeta: object) {
-  var partial = '';
+  let partial = '';
-  return data => {
+  return (data: Uint8Array) => {
     partial += MemBuffer.arrayToString(data);
-    var newline;
+    let newline;
     while ((newline = partial.indexOf("\n")) !== -1) {
-      var line = partial.slice(0, newline);
+      const line = partial.slice(0, newline);
       partial = partial.slice(newline + 1);
       // Escape some parts of the string by serializing it to JSON (without the quotes).
-      log.rawInfo(prefix + JSON.stringify(line).slice(1, -1).replace(/\\"/g, '"')
+      log.origLog('info', "%s%s", prefix,
-        .replace(/\\\\/g, '\\'),
+        JSON.stringify(line).slice(1, -1).replace(/\\"/g, '"').replace(/\\\\/g, '\\'),
         logMeta);
     }
   };
 }
-exports.makeLinePrefixer = makeLinePrefixer;

test/server/testUtils.ts

@@ -126,7 +126,7 @@ export function setTmpLogLevel(level: string, optCaptureFunc?: (level: string, m
  * captures those at minLevel and higher. Returns a promise for the array of "level: message"
  * strings. These may be tested using testUtils.assertMatchArray(). Callback may return a promise.
  */
-export async function captureLog(minLevel: string, callback: any) {
+export async function captureLog(minLevel: string, callback: () => void|Promise<void>): Promise<string[]> {
   const messages: string[] = [];
   const prevLogLevel = log.transports.file.level;
   const name = _.uniqueId('CaptureLog');