Inline workers does not work in Edge Legacy anymore

[mpk]

• Operating System: Windows 10
• Node Version: 12.14.0
• NPM Version: 6.13.4
• webpack Version: 4.44.2
• worker-loader Version: 3.0.3

Expected Behavior

Inline worker should execute in Edge Legacy

Actual Behavior

Inline worker does not execute in Edge Legacy

Code

// webpack.config.js
let HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = {
    entry: './index.js',
    plugins: [new HtmlWebpackPlugin()]
};

// index.js
import TestWorker from 'worker-loader?inline=no-fallback!./worker';

let worker = new TestWorker();
console.log(worker);

// worker.js
console.log('Log from worker');

How Do We Reproduce?

The code should write "Log from worker" into the console. However, it does not work in Edge Legacy browser (tested on version 18.18363). The worker is created successfully, but its contents are not executed, so nothing gets logged into the console.

I have looked at the worker-loader code and found out that the problem is in URL.revokeObjectURL(objectURL); line in inline.js. When I commented out that line, Edge executed the worker contents. Wrapping the call in setTimeout with 1000ms delay worked as well, but that solution seems quite hacky.

This issue is not present in worker-loader 2.0.0

[alexander-akait]

Feel free to send a fix:

if (URL.revokeObjectURL) {
  URL.revokeObjectURL(objectURL);
}

Should be easy

[mpk]

No, Edge Legacy actually supports URL.revokeObjectURL, but it does not like when the Blob URL is revoked "too quickly".

[Rush]

inline workers stopped working for me after upgrading to 3.x and changing inline: true to inline: 'no-fallback'

Investigating network shows a script with contents:

importScripts('http://localhost:4000/[object%20Module]');

[alexander-akait]

@mpk Can you create reproducible test repo?

[alexander-akait]

@Rush It is not you problem, please provide reproducible test repo, I will help

[mpk]

@evilebottnawi Sure, here you go: https://github.com/mpk/worker-loader-edge

[alexander-akait]

@mpk to be honestly I can't reproduce :confused:

[KallynGowdy]

I'm having a similar issue with Chrome (87.0.4280.88) and Edgium (87.0.664.55) on worker-loader v3.0.6 with webpack v5.10.0. It is worth noting that the worker loads fine on Firefox.

Definitely seems like a race condition because if I put a breakpoint at inline.js line 31 and continue after half a second then the worker loads correctly but if I disable the breakpoint then it does not load.

In light of this, the root cause appears to actually be a Chrome bug however I haven't found anything in their bug tracker.

[Shravan-Joopally]

I could reproduce this issue consistently on IE 11. Definitely revoking the object url immediately is issue. If I tried below code its working fine.

import TestWorker from 'worker-loader?inline=no-fallback!./worker';

let tmp = URL.revokeObjectURL;
URL.revokeObjectURL = function() {};

let worker = new TestWorker();

URL.revokeObjectURL = tmp;

console.log(worker);

[alexander-akait]

Can you check revokeObjectURL is exist?

[Shravan-Joopally]

yes its there

[alexander-akait]

Weird, it should work, no errors? Can you add try/catch for revokeObjectURL and check again

[Shravan-Joopally]

yeah, no errors

[alexander-akait]

Looks bug in browser...

[lawrence-witt]

I'm also running into this issue with inline workers in IE11. Changing the URL revocation in inline.js to the following fixes it in my use case:

setTimeout(function() { URL.revokeObjectURL(objectURL) });

[alexander-akait]

Very very very weird, somebody can provide versions and steps to reproduce, I am not against to fix it using setTimeout, but I want to investigate it

[elasim]

Is there any chance to merge the patch about setTimeout on above or the other plan for this issue?

[alexander-akait]

@elasim Can you provide screenshot/etc of the problem?

[elasim]

In this case, the screenshot is useless. there are no exception or error throws for this. following is the information about reproduced environment.

UA: Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; Tablet PC 2.0; rv:11.0) like Gecko WinVer 20H2.19042.928

test-project
├── @babel/plugin-transform-runtime@7.13.15
├── @babel/preset-env@7.14.1
├── @babel/runtime-corejs3@7.14.0
├── eslint@7.25.0
├── typescript@4.2.4
├── webpack@5.35.1
├── webpack-dev-server@3.11.0
├── babel-loader@8.2.2
├── eventemitter3@4.0.7
├── fast-xml-parser@3.19.0
├── source-map-loader@2.0.1
├── tslib@2.2.0
└── worker-loader@3.0.8

// webpack.config.js
const path = require("path");

module.exports = ({ production }) => {
  const webpackConfig = {
    // Documentation: https://webpack.js.org/configuration/mode/
    mode: production ? "production" : "development",
    resolve: {
      extensions: [".js", ".jsx", ".json"],
    },
    module: {
      rules: [
        {
          test: /\-worker\.js$/,
          use: {
            loader: "worker-loader",
            options: {
              inline: "no-fallback",
            },
          },
        },
        {
          test: /\.js$/,
          exclude: [/node_modules/],
          use: [
            {
              loader: "babel-loader",
              options: {
                presets: [
                  [
                    "@babel/preset-env",
                    {
                      targets: {
                        browsers: [
                          "chrome >= 51",
                          "firefox >= 51",
                          "ie >= 11",
                          "safari >= 8",
                          "ios >= 9",
                          "android >= 5",
                        ],
                      },
                    },
                  ],
                ],
                plugins: [
                  [
                    "@babel/plugin-transform-runtime",
                    {
                      absoluteRuntime: false,
                      corejs: 3,
                      helpers: true,
                      regenerator: true,
                    },
                  ],
                ],
              },
            },
          ],
        },
        {
          test: /\.js$/,
          enforce: "pre",
          use: ["source-map-loader"],
        },
      ],
    },
    entry: {
      test: path.join(__dirname, "lib", "index.js"),
    },
    output: {
      path: path.join(__dirname, "dist"),
      filename: "[name].es5.js",
      environment: {
        arrowFunction: false,
        bigIntLiteral: false,
        const: true,
        destructuring: false,
        dynamicImport: false,
        forOf: false,
        module: false,
      },
    },
    performance: {
      maxEntrypointSize: 250000,
      maxAssetSize: 250000,
    },
    devtool: production ? undefined : "source-map",
  };

  return webpackConfig;
};

[alexander-akait]

hm, code is just not executed? Can you add console.log('BEFORE') and `console.log('After') between https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L35 in your bundled code?

[elasim]

seems like worker is forked with empty script.

[alexander-akait]

Can you console log https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L23 content and blob and show me it here?

[elasim]

Can you console log https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L23 content and blob and show me it here?

Are you sure L23 is the place what you want to put logpoint? (Blob is supported natively, so that line wasn't executed.) btw, it is the log of content and blob

Chrome

IE11

/******/ (function() { // webpackBootstrap
/******/    "use strict";
/******/    // The require scope
/******/    var __webpack_require__ = {};
/******/    
/************************************************************************/
/******/    /* webpack/runtime/define property getters */
/******/    !function() {
/******/        // define getter functions for harmony exports
/******/        __webpack_require__.d = function(exports, definition) {
/******/            for(var key in definition) {
/******/                if(__webpack_require__.o(definition, key) && !__webpack_require__.o(exports, key)) {
/******/                    Object.defineProperty(exports, key, { enumerable: true, get: definition[key] });
/******/                }
/******/            }
/******/        };
/******/    }();
/******/    
/******/    /* webpack/runtime/hasOwnProperty shorthand */
/******/    !function() {
/******/        __webpack_require__.o = function(obj, prop) { return Object.prototype.hasOwnProperty.call(obj, prop); }
/******/    }();
/******/    
/******/    /* webpack/runtime/make namespace object */
/******/    !function() {
/******/        // define __esModule on exports
/******/        __webpack_require__.r = function(exports) {
/******/            if(typeof Symbol !== 'undefined' && Symbol.toStringTag) {
/******/                Object.defineProperty(exports, Symbol.toStringTag, { value: 'Module' });
/******/            }
/******/            Object.defineProperty(exports, '__esModule', { value: true });
/******/        };
/******/    }();
/******/    
/************************************************************************/
var __webpack_exports__ = {};
/*!*************************************************************************************************************************************************************************************************************************************************************!*\
  !*** ../../common/temp/node_modules/.pnpm/babel-loader@8.2.2/node_modules/babel-loader/lib/index.js??ruleSet[1].rules[1].use[0]!../../common/temp/node_modules/.pnpm/source-map-loader@2.0.1/node_modules/source-map-loader/dist/cjs.js!./lib/ie-worker.js ***!
  \*************************************************************************************************************************************************************************************************************************************************************/
__webpack_require__.r(__webpack_exports__);
/* harmony export */ __webpack_require__.d(__webpack_exports__, {
/* harmony export */   "default": function() { return __WEBPACK_DEFAULT_EXPORT__; }
/* harmony export */ });
function handleMessage(event) {
  self.postMessage(event.data);
}

self.addEventListener("message", handleMessage);

var default_1 =
/** @class */
function () {
  function default_1() {}

  return default_1;
}();

/* harmony default export */ const __WEBPACK_DEFAULT_EXPORT__ = (default_1);
/******/ })()
;

[alexander-akait]

I want to look at blob content here https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L29, maybey BlobBuilder or getBlob is broken

[elasim]

It's not. BlobBuilder won't used. https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L14-L25 is never reached because globalScope.Blob is available.

and Blob data is not broken either as you can see.

[alexander-akait]

Can you show blob value here https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L29, here two places for bug

• blob generation is broken
• URL.createObjectURL is broken with blob
• URL.revokeObjectURL is broken without any reports

Also do you have CORS or other security headers?

[elasim]

I've already attached. see the last line of logs.

• blob generation is broken: No. It's working If I commented out revokeObjectURL or give some delay using setTimeout.
• CORS or Security Header: No. this script served via webpack-dev-server. there are no such a security header.
• URL.createObjectURL is broken with blob: No. As you can see the last image, We can read blob data via xhr and there are no error.
• URL.revokeObjectURL is broken without any reports: Maybe. but no way to figure out.

[alexander-akait]

What about setImmediate? Can you try? Maybe we can check setImmediate is defined and use logic, so for good browser we will keep original logic

[elasim]

https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L35

Replacing that line with globalScope.setImmediate(URL.revokeObjectURL, objectURL); works.

oops, no. Above approach throws an error on safari. I'll try another way.

It works now.

if (globalScope.setImmediate) {
  globalScope.setImmediate(URL.revokeObjectURL, objectURL);
} else {
  globalScope.setTimeout(0, URL.revokeObjectURL, objectURL);
}

[alexander-akait]

Ideally we need if (globalScope.setImmediate) { globalScope.setImmediate(() => { URL.revokeObjectURL(objectURL) }); } else { URL.revokeObjectURL(objectURL); }

[elasim]

Ideally we need if (globalScope.setImmediate) { globalScope.setImmediate(() => { URL.revokeObjectURL(objectURL) }); } else { URL.revokeObjectURL(objectURL); }

This one also works.

It seems like IE/Edge wasn't implement Web Worker API properly like the other API implementations does. 😢

[alexander-akait]

Feel free to send a fix to our runtime if it is work https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L35, no need tests, just add comment about version and problem

[elasim]

if (globalScope.setImmediate) { globalScope.setImmediate(() => { URL.revokeObjectURL(objectURL) }); } else { URL.revokeObjectURL(objectURL); }

I've found a bug for this approach. After blob url is revoked, Invoking URL.createObjectURL from IE11 worker context throws an error. Perhaps we should have to leave object url without revoking or revoke that when the worker terminated.

[alexander-akait]

Can you clarify?

[elasim]

Here is pseudo code to reproduce.

// inline-worker.js
self.addEventListener('message', ({ data }) => {
  // (IE bug) this line throw an error If objectUrl is revoked for this inline worker
  const url = URL.createObjectURL(new Blob(['something']));

  self.postMessage({ url });
});

// main.js
const objectUrl = URL.createObjectUrl(inlineWorkerBlob);
const worker = new Worker(objectUrl);

worker.addEventListener('message', () => {
  URL.revokeObjectUrl(objectUrl);
});

setTimeout(() => {
  // expect to success, actual also succeed.
  worker.postMessage(1);
}, 1000);
setTimeout(() => {
  // expect to success, actual is fail because of bug on IE.
  // objectUrl was revoked at first callback event
  worker.postMessage(2);
}, 2000);

[alexander-akait]

I don't understand...

[elasim]

Okay, maybe I'll capture some video stub with example repo for your understand.

[alexander-akait]

What are you trying to achieve? I don't understand at all, here is a browser problem and that's it. We need search approach to fix it.

[elasim]

Oh, sorry to keep bother you. I was completely lost. I was telling you what's the issue is.

So, back to how to fix it. Maybe we got 2 options.

1. Give up self-closing and delegate revoking to the author who people using it.

// inline.js
worker = new Worker(objectUrl);
worker.objectUrl = objectUrl;

return worker

// usage.js
const worker = new InlineWorker();

worker.close();
URL.revokeObjectURL(worker.objectUrl); // revoke by author

2. Putting some codes to revoke when it closed. perhaps we need some special message for this and it will need to change original behavior. like following stub. (I know it's messy. but I want to review all the option we can try)

// Inject stub if worker launched inline worker. (but we can't determine that at compile-time.)
// maybe here? https://github.com/webpack-contrib/worker-loader/blob/22275e9cb0b67bc008ea2b008542303493eede18/src/utils.js#L84
var origTerminate = worker.terminate;
worker.terminate = () => {
  URL.revokeObjectURL(objectUrl);
  return origTerminate.call(worker);
};
worker.addEventListener('message', ({ data }) => {
  if (data === ''$specialMessageForClosing'') {
    URL.revokeObjectURL(objectUrl);
  }
});

var origClose = self.close;
self.close = () => {
  self.postMessage('$specialMessageForClosing');
  origClose.call(self);
}

I think option-1 is reasonable.

[alexander-akait]

If you forget to run URL.revokeObjectURL, you will have memory leak, If this problem is so complex I would rather say that we do not support workers in Edge Legacy browsers due bug in browsers and you can write workaround on application side.

If you need deeply help, please create reproducible repo, provide version of browser(s) and os information. I will write to Microsoft and ask them how we can fix it.

[elasim]

What about adding new option for manual revoke? Is it too complicated? I'll post reproducible repo anyway.

[alexander-akait]

I want to avoid new options if we can solve it on code level

[elasim]

I attached reproducible link and test results. Also, I'm not used webpack or worker-loader on this testbed intentionally to make it sure the issue is coming from URL.revokeObjectURL.

https://elasim.github.io/test/ie-inline-worker-bug

Browser version	Result
Win7 IE 11	X
Win11 IE 11	X
Edge 15	X
Edge 16	X
Edge 17	X
Edge 18	X
Edge 80	O

[alexander-akait]

hm, we can add window.navigator.msSaveOrOpenBlob check and if it is true we should always run https://github.com/webpack-contrib/worker-loader/blob/master/src/runtime/inline.js#L39

[elasim]

• there are security error with using data-uri.
• temporal URL.revokeObjectURL patching isn't useful with core-js is used.
• app side workaround isn't acceptable with some use-case because of heavy workload.

by the way, we probably can merge PR #316 and write caveat about this issue on document or just close that. I'll respect your decision.

[alexander-akait]

there are security error with using data-uri.

What is the problem? Do you mean CORS?

[elasim]

What is the problem? Do you mean CORS?

Umm.. It was script5022: securityerror. and seems like a restriction rather than CORS. https://docs.microsoft.com/en-us/previous-versions//cc848897(v=vs.85)?redirectedfrom=MSDN

Also, It could be CORS. After some investigation, I've found the information about spec for data-uri and same-origin-policy from stackoverflow. (https://stackoverflow.com/a/23895830) It said same-origin-policy was changed for data-uri and that wasn't applied to data-uri before.

[alexander-akait]

But this problem should be same with blob too

[elasim]

I agree that too. But spec and actual behavior is does. (IE is annoying and frustrating always does 🤣)

Back to solution.

I want to suggest about two loader which is splited from current implementation.

first is child compiler which output will be string. second is code injector which are depend first one and output will be same as current implements

author can choose one of them. and if you don't want to make any breaking changes, Perhaps I need to make fork version of this. (Only if you and CLA agree with this)

[alexander-akait]

What is webpack version you are use?