Cannot read properties of undefined (reading 'length') #16218

sebastianrath · 2022-09-05T04:39:34Z

sebastianrath
Sep 5, 2022

Hey there,

I am upgrading my webpack dependency in my Electron app from 4.46.0 to the latest 5.74.0. I am running into the following error message when building my project:

⠇ Generating browser application bundles (phase: building).../
       /../node_modules/webpack/lib/util/hash/wasm-hash.js:108
                const length = data.length;

TypeError: Cannot read properties of undefined (reading 'length')
    at WasmHash._updateWithBuffer (/.../node_modules/webpack/lib/util/hash/wasm-hash.js:108:23)
    at WasmHash.update (/.../node_modules/webpack/lib/util/hash/wasm-hash.js:51:8)
    at BatchedHash.update (/.../node_modules/webpack/lib/util/hash/BatchedHash.js:50:14)
    at /.../node_modules/webpack/lib/FileSystemInfo.js:3464:11
    at processQueue (/.../node_modules/webpack/lib/util/processAsyncTree.js:55:4)
    at processTicksAndRejections (node:internal/process/task_queues:78:11)

webpack/lib/util/hash/wasm-hash.js

Lines 106 to 108 in 9fcaa24

    
           _updateWithBuffer(data) { 
        
           	const { exports, buffered, mem } = this; 
        
           	const length = data.length;

This is the content of the webpack.config.js:

const MonacoWebpackPlugin = require('monaco-editor-webpack-plugin');
const NodePolyfillPlugin = require("node-polyfill-webpack-plugin");

const path = require('path');

let sassImplementation = require('sass');

module.exports = {
	output: {
		path: path.resolve(__dirname, 'build-js'),
		filename: 'app.js'
	},
  externals: {
    'fsevents': "require('fsevents')"
  },
	plugins: [new MonacoWebpackPlugin(),
    new NodePolyfillPlugin({
      excludeAliases: ["console"]
    })
  ],
  target: 'electron-renderer',
  module: {
    rules: [
      {
        test: /\.css$/i,
				use: ['style-loader', 'css-loader']
      },
      {
        test: /\.scss$/,
        use: [
          'postcss-loader',
          {
            loader: 'sass-loader',
            options: {
              implementation: sassImplementation,
              sourceMap: false,
              sassOptions: {
                precision: 8,
              },
            },
          },
        ],
      },
    ],
  },
};

Does anything stand out that could cause this, or is this an issue in webpack? Any help is highly appreciated.

Thanks!

alexander-akait · 2022-09-05T16:52:55Z

alexander-akait
Sep 5, 2022
Maintainer

I think a bug somewhere in monaco-editor-webpack-plugin. Does monaco-editor-webpack-plugin use the latest webpack-sources?

14 replies

yoyo837 Apr 5, 2023

alexander-akait Apr 5, 2023
Maintainer

It means you have old webpack plugin which doesn't update own code to v5

adonis-lsh Apr 10, 2023

me too

lyztroy Apr 24, 2023

i have the same problem. what should I do ?

alexander-akait Apr 24, 2023
Maintainer

Run npm ls webpack

artemis-prime · 2024-05-12T00:59:34Z

artemis-prime
May 12, 2024

I'm seeing this in next 14.1.3... seemingly out of nowhere

14 replies

phinpho Oct 30, 2024

@alexander-akait, I'm redacting some details for security reasons, but I think it will be fine for analyzing the Stack Trace.

When I run the Next.js dev server (very early on), the latest line of the command output is ✓ Ready in 1526ms. When I try to access the page with the path /[slug]/page in the browser, it shows the following logs and the page gets stuck. The latest message in the logs is ○ Compiling /404 ..., anything else (except if I interrupt the process).

The command:

npm run dev

In the package.json, the property scripts.dev has the following value:

"NODE_OPTIONS='--trace-deprecation' next dev"

The result:

  ▲ Next.js 14.2.16
  - Local:        http://localhost:3000
  - Experiments (use with caution):
    · externalDir
    · scrollRestoration
    · forceSwcTransforms

 ✓ Starting...
 ✓ Ready in 3s
 ✓ Compiled /src/middleware in 162ms (142 modules)
 ○ Compiling /[slug]/page ...
 ✓ Compiled /[slug]/page in 4s (994 modules)
(node:57213) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
    at node:punycode:3:9
    at BuiltinModule.compileForInternalLoader (node:internal/bootstrap/realm:399:7)
    at BuiltinModule.compileForPublicLoader (node:internal/bootstrap/realm:338:10)
    at loadBuiltinModule (node:internal/modules/helpers:96:7)
    at Module._load (node:internal/modules/cjs/loader:1070:17)
    at TracingChannel.traceSync (node:diagnostics_channel:315:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:215:24)
    at Module.require (node:internal/modules/cjs/loader:1304:12)
    at mod.require ([[--PROJECT-PATH--]]/node_modules/next/dist/server/require-hook.js:65:28)
    at require (node:internal/modules/helpers:123:16)
    at Object.<anonymous> ([[--PROJECT-PATH--]]/node_modules/node-fetch/node_modules/whatwg-url/lib/url-state-machine.js:2:18)
    at Module._compile (node:internal/modules/cjs/loader:1504:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1588:10)
    at Module.load (node:internal/modules/cjs/loader:1282:32)
    at Module._load (node:internal/modules/cjs/loader:1098:12)
TypeError: Cannot read properties of undefined (reading 'length')
    at WasmHash._updateWithBuffer ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1384455)
    at WasmHash.update ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1383790)
    at BatchedHash.update ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1380151)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:297115
    at processQueue ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1397772)
    at processAsyncTree ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1397778)
    at FileSystemInfo._resolveContextTimestamp ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:296723)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:270356
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1333530
    at Hook.eval [as callAsync] (eval at create ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:13:28858), <anonymous>:6:1)
    at AsyncQueue._handleResult ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1333084)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1332935
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:296661
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:295397
    at done ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/neo-async/async.js:1:10300)
 ⨯ uncaughtException: TypeError: Cannot read properties of undefined (reading 'length')
    at WasmHash._updateWithBuffer ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1384455)
    at WasmHash.update ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1383790)
    at BatchedHash.update ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1380151)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:297115
    at processQueue ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1397772)
    at processAsyncTree ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1397778)
    at FileSystemInfo._resolveContextTimestamp ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:296723)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:270356
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1333530
    at Hook.eval [as callAsync] (eval at create ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:13:28858), <anonymous>:6:1)
    at AsyncQueue._handleResult ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1333084)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1332935
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:296661
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:295397
    at done ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/neo-async/async.js:1:10300)
 ⨯ uncaughtException: TypeError: Cannot read properties of undefined (reading 'length')
    at WasmHash._updateWithBuffer ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1384455)
    at WasmHash.update ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1383790)
    at BatchedHash.update ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1380151)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:297115
    at processQueue ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1397772)
    at processAsyncTree ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1397778)
    at FileSystemInfo._resolveContextTimestamp ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:296723)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:270356
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1333530
    at Hook.eval [as callAsync] (eval at create ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:13:28858), <anonymous>:6:1)
    at AsyncQueue._handleResult ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1333084)
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:1332935
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:296661
    at [[--PROJECT-PATH--]]/node_modules/next/dist/compiled/webpack/bundle5.js:28:295397
    at done ([[--PROJECT-PATH--]]/node_modules/next/dist/compiled/neo-async/async.js:1:10300)
 ○ Compiling /404 ...

Node Version:

22.5.1

NPM Version:

10.8.2

Versions of some packages found in the package-lock.json file:

Package	Version
`node_modules/neo-async`	2.6.2
`node_modules/next`	14.2.16
`node_modules/webpack`	5.95.0
`node_modules/webpack-bundle-analyzer`	4.10.1
`node_modules/webpack-dev-middleware`	6.1.3
`node_modules/webpack-hot-middleware`	2.26.1
`node_modules/webpack-sources`	3.2.3
`node_modules/webpack-virtual-modules`	0.5.0
`node_modules/unplugin`	1.14.1
`node_modules/unplugin/node_modules/webpack-virtual-modules`	0.6.2

Let me know if you need more information

alexander-akait Oct 30, 2024
Maintainer

webpack-virtual-modules can be a problem, when trying to create a hash, but for some reason our content is undefined, here the place - https://github.com/webpack/webpack/blob/main/lib/util/hash/wasm-hash.js#L42, I asked for the stack so I could see where it came from, but apparently it happens in the hook so the stack is dirty, https://github.com/webpack/webpack/blob/main/lib/FileSystemInfo.js#L3582 - the main problem here is how to we work with directories, you can debug which directory is a problem, hashes are - https://github.com/webpack/webpack/blob/main/lib/FileSystemInfo.js#L3607 and https://github.com/webpack/webpack/blob/main/lib/FileSystemInfo.js#L3613

Can you debug? Maybe we should add undefined checks, but this may lead to the fact that the directory change will not be tracked by the timestamp. Need a little more information

alexander-akait Oct 30, 2024
Maintainer

To debug we need entry value and hashes - https://github.com/webpack/webpack/blob/main/lib/FileSystemInfo.js#L3606

yue4u Nov 22, 2024

I just encountered a similar error using storybook

  entry: {
    safeTime: 1732269935475,
    timestampHash: '6fa9cbf877b15bff2026d0cfa34364cf',
    hash: '2c6dac90603fc802b664d11e672aad55',
    symlinks: Set(1) {
      '/Users/<redacted>'
    }
  },
  hashes: [ '1c7c4e56b8455609a99c91f0940bfef8', undefined, undefined ]
}
/Users/<redacted>/node_modules/@storybook/cli/bin/index.js:23
  throw error;
  ^

TypeError: Cannot read properties of undefined (reading 'length')
    at WasmHash._updateWithBuffer (/Users/<redacted>/node_modules/webpack/lib/util/hash/wasm-hash.js:108:23)
    at WasmHash.update (/Users/<redacted>/node_modules/webpack/lib/util/hash/wasm-hash.js:51:8)
    at BatchedHash.update (/Users/<redacted>/node_modules/webpack/lib/util/hash/BatchedHash.js:50:14)
    at /Users/<redacted>/node_modules/webpack/lib/FileSystemInfo.js:3518:12
    at processQueue (/Users/<redacted>/node_modules/webpack/lib/util/processAsyncTree.js:61:4)
    at process.processTicksAndRejections (node:internal/process/task_queues:85:11)

Node.js v22.11.0

alexander-akait Nov 25, 2024
Maintainer

@yue4u Can you create a reproducible repository?

aheritier · 2024-12-19T13:15:36Z

aheritier
Dec 19, 2024

We faced the issue on our CI in august and it just reappears.
We were thinking it could be due to some invalid symbolic links in node_modules but today we don't find any of them. it's hard to create a testcase to reproduce the issue because it happens only on our CI and it could be related with the cache management.
Not sure how to debug this issue.

8 replies

alexander-akait Dec 19, 2024
Maintainer

Can you debug this place - #16218 (reply in thread)

aheritier Dec 19, 2024

A theory we had in the past is that the we had an invalid symlink pointing to nothing. In August it's by removing such anomaly that we thought we solved the issue. Sadly I verified on our current node_modules folder and there is no broken link.

We are not using nextjs but react, now with the number of dependencies we have on our monolith it is highly possible that we use something deprecated plugins. I am looking at your link

alexander-akait Dec 19, 2024
Maintainer

@aheritier As another solution, you can try to create a reproducible repository or give me private access to the stag project (just send invite) (I can sign an NDA) and I will see why this is happening

aheritier Dec 19, 2024

npm ls webpack gives me this:

acme@ /Users/arnaud/Workspace/dev/acme/acme
├─┬ @pmmmwh/react-refresh-webpack-plugin@0.5.15
│ └── webpack@5.91.0 deduped
├─┬ @storybook/react-webpack5@8.1.1
│ ├─┬ @storybook/builder-webpack5@8.1.1
│ │ ├─┬ fork-ts-checker-webpack-plugin@8.0.0
│ │ │ └── webpack@5.91.0 deduped
│ │ ├─┬ html-webpack-plugin@5.6.0
│ │ │ └── webpack@5.91.0 deduped
│ │ ├─┬ style-loader@3.3.4
│ │ │ └── webpack@5.91.0 deduped
│ │ ├─┬ webpack-dev-middleware@6.1.3
│ │ │ └── webpack@5.91.0 deduped
│ │ └── webpack@5.91.0 deduped
│ └─┬ @storybook/preset-react-webpack@8.1.1
│   ├─┬ @storybook/react-docgen-typescript-plugin@1.0.6--canary.9.0c3f3b7.0
│   │ └── webpack@5.91.0 deduped
│   └── webpack@5.91.0 deduped
├─┬ @webpack-cli/serve@2.0.5
│ └── webpack@5.91.0 deduped
├─┬ babel-loader@9.2.1
│ └── webpack@5.91.0 deduped
├─┬ circular-dependency-plugin@5.2.2
│ └── webpack@5.91.0 deduped
├─┬ css-loader@6.10.0
│ └── webpack@5.91.0 deduped
├─┬ css-minimizer-webpack-plugin@6.0.0
│ └── webpack@5.91.0 deduped
├─┬ imports-loader@5.0.0
│ └── webpack@5.91.0 deduped
├─┬ mini-css-extract-plugin@2.9.2
│ └── webpack@5.91.0 deduped
├─┬ postcss-loader@8.1.1
│ └── webpack@5.91.0 deduped
├─┬ sass-loader@16.0.3
│ └── webpack@5.91.0 deduped
├─┬ style-loader@4.0.0
│ └── webpack@5.91.0 deduped
├─┬ terser-webpack-plugin@5.3.10
│ └── webpack@5.91.0 deduped
├─┬ webpack-assets-manifest@5.2.1
│ └── webpack@5.91.0 deduped
├─┬ webpack-cli@5.1.4
│ ├─┬ @webpack-cli/configtest@2.1.1
│ │ └── webpack@5.91.0 deduped
│ ├─┬ @webpack-cli/info@2.0.2
│ │ └── webpack@5.91.0 deduped
│ └── webpack@5.91.0 deduped
├─┬ webpack-dev-server@5.1.0
│ ├─┬ webpack-dev-middleware@7.4.2
│ │ └── webpack@5.91.0 deduped
│ └── webpack@5.91.0 deduped
├── webpack@5.91.0
└─┬ zipper@89.8.0 -> ./packages/zipper
  ├─┬ raw-loader@4.0.2
  │ └── webpack@5.91.0 deduped
  ├─┬ ts-loader@9.5.1
  │ └── webpack@5.91.0 deduped
  └── webpack@5.91.0 deduped

We will continue to investigate with our teammates tomorrow

alexander-akait Dec 19, 2024
Maintainer

I don't see anything very dangerous...

Maybe you can try to create a reproducible repository? Just comment lines step by step and look when it happend

gitmahin · 2025-04-15T13:56:40Z

gitmahin
Apr 15, 2025

I faced this same issue in Next.js 15, but solved it by deleting node_modules and reinstalling everything.

1 reply

yiheee-lab Jul 20, 2025

True but it keep happening and make things super frustrated.

yiheee-lab · 2025-07-20T07:49:59Z

yiheee-lab
Jul 20, 2025

Well for Nextjs with tauri, try disable WASM.

next.config.ts

const nextConfig: NextConfig = {
  webpack: (config) => {
    config.experiments = {
      ...config.experiments,
      asyncWebAssembly: false,
      syncWebAssembly: false,
    };
    return config;
  },
};

0 replies

Uh oh!

Cannot read properties of undefined (reading 'length') #16218

Uh oh!

Replies: 5 comments · 37 replies

Uh oh!

alexander-akait Sep 5, 2022 Maintainer

Uh oh!

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alexander-akait Apr 5, 2023 Maintainer

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alexander-akait Apr 24, 2023 Maintainer

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alexander-akait Oct 30, 2024 Maintainer

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alexander-akait Oct 30, 2024 Maintainer

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alexander-akait Nov 25, 2024 Maintainer

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alexander-akait Dec 19, 2024 Maintainer

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alexander-akait Dec 19, 2024 Maintainer

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alexander-akait Dec 19, 2024 Maintainer

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Replies: 5 comments 37 replies

alexander-akait
Sep 5, 2022
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alexander-akait Apr 24, 2023
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alexander-akait Oct 30, 2024
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alexander-akait Nov 25, 2024
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alexander-akait Dec 19, 2024
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alexander-akait Dec 19, 2024
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