Fix DataCloneError with Prettier plugins containing functions in PNPM projects

[Copilot]

Prettier plugins (e.g., prettier-plugin-sh) can include functions in their configuration that cannot be serialized when passed across worker boundaries, causing DataCloneError. If getSupportInfo fails, the extension crashes on undefined.forEach.

Changes

• Added sanitizePlugin() function: Recursively strips function properties from plugin objects before passing to Prettier APIs, preserving all serializable configuration
• Error handling for getSupportInfo calls: Wrapped both invocations in try-catch with empty array fallbacks, allowing extension to continue with default language support
• Nullish coalescing: Changed || to ?? for precise null-safety semantics

// Before: plugin objects with functions passed directly
resolvedPlugins.push(plugin);

// After: functions removed recursively
resolvedPlugins.push(sanitizePlugin(plugin));

// Before: unguarded call that can throw
const { languages } = await prettierInstance.getSupportInfo({ plugins });
languages.forEach(lang => { ... }); // crashes if getSupportInfo returns undefined

// After: graceful degradation
let languages = [];
try {
  const supportInfo = await prettierInstance.getSupportInfo({ plugins });
  languages = supportInfo?.languages ?? [];
} catch (error) {
  this.loggingService.logError("Failed to get support info...", error);
}
languages.forEach(lang => { ... }); // safe

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://storage.googleapis.com/chrome-for-testing-public/143.0.7499.4/linux64/chrome-headless-shell-linux64.zip
  • Triggering command: /usr/local/bin/node /usr/local/bin/node /home/REDACTED/work/prettier-vscode/prettier-vscode/node_modules/playwright-core/lib/server/registry/oopDownloadBrowserMain.js (http block)
• https://storage.googleapis.com/chrome-for-testing-public/143.0.7499.4/linux64/chrome-linux64.zip
  • Triggering command: /usr/local/bin/node /usr/local/bin/node /home/REDACTED/work/prettier-vscode/prettier-vscode/node_modules/playwright-core/lib/server/registry/oopDownloadBrowserMain.js (http block)
• update.code.visualstudio.com
  • Triggering command: /usr/local/bin/node node /home/REDACTED/work/prettier-vscode/prettier-vscode/node_modules/.bin/vscode-test --grep plugins -150�� test && node scripts/install-fixtures.mjs (dns block)

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>DOMError when in PNPM package and using prettier plugin</issue_title>
<issue_description>### Preflight Checklist

• I have read the troubleshooting guide
• I have searched existing issues and this is not a duplicate
• This is a bug with the VS Code extension, not with how Prettier formats code

Issue Summary

Prettier VSCode extension fails with an exception when run in a PNPM project, and prettier config has at least one plugin.

This is a follow up on #3036 and #3037 which were closed without a fix

Reproduction Repository

https://github.com/maxpatiiuk/pnpm-prettier-vscode

Steps to Reproduce

1. Clone repository

   git clone https://github.com/maxpatiiuk/pnpm-prettier-vscode
   cd pnpm-prettier-vscode

2. Run PNPM install:

   pnpm i

3. Open VSCode and go to the "Output" tab.

   Open ./README.md then switch to ./test.ts.

   See exception in the console.

   Also, file is not formatted on save.

   Comment out the plugin in prettier.config.js and restart vscode - the error is gone.

Expected Behavior

No exception

Actual Behavior

Code is not reformated. VSCode Output for Prettier plugin contains:

["INFO" - 5:55:51 PM] Extension Name: esbenp.prettier-vscode.
["INFO" - 5:55:51 PM] Extension Version: 11.0.2.
["DEBUG" - 5:55:51 PM] Enabling Prettier globally
{
  "languageSelector": [
    {
      "language": "javascript"
    },
    {
      "language": "mongo"
    },
    {
      "language": "javascriptreact"
    },
    {
      "language": "typescript"
    },
    {
      "language": "typescriptreact"
    },
    {
      "language": "json"
    },
    {
      "language": "jsonc"
    },
    {
      "language": "json5"
    },
    {
      "language": "css"
    },
    {
      "language": "postcss"
    },
    {
      "language": "less"
    },
    {
      "language": "scss"
    },
    {
      "language": "handlebars"
    },
    {
      "language": "graphql"
    },
    {
      "language": "markdown"
    },
    {
      "language": "mdx"
    },
    {
      "language": "html"
    },
    {
      "language": "vue"
    },
    {
      "language": "yaml"
    },
    {
      "language": "ansible"
    },
    {
      "language": "home-assistant"
    },
    {
      "language": "jsonc",
      "scheme": "vscode-userdata"
    }
  ],
  "rangeLanguageSelector": [
    {
      "language": "javascript"
    },
    {
      "language": "javascriptreact"
    },
    {
      "language": "typescript"
    },
    {
      "language": "typescriptreact"
    },
    {
      "language": "json"
    },
    {
      "language": "jsonc"
    },
    {
      "language": "graphql"
    }
  ]
}
["DEBUG" - 5:55:55 PM] Local prettier module path: /Users/mak13180/s/e/pnpm-prettier-vscode/node_modules/prettier/index.cjs
["DEBUG" - 5:55:55 PM] Using prettier version 3.8.0
["INFO" - 5:55:55 PM] Using config file at /Users/mak13180/s/e/pnpm-prettier-vscode/prettier.config.js
["ERROR" - 5:55:55 PM] Error handling text editor change
["ERROR" - 5:55:55 PM] function({ filepath }) {
      const basename = path.basename(filepath);
      return basename === ".env" || ba...<omitted>... } could not be cloned.
DataCloneError: function({ filepath }) {
      const basename = path.basename(filepath);
      return basename === ".env" || ba...<omitted>... } could not be cloned.
    at new DOMException (node:internal/per_context/domexception:76:18)
    at p (/Users/mak13180/Documents/code/code-portable-data/extensions/esbenp.prettier-vscode-11.0.2/dist/worker/prettier-instance-worker.js:37:22)
    at /Users/mak13180/Documents/code/code-portable-data/extensions/esbenp.prettier-vscode-11.0.2/dist/worker/prettier-instance-worker.js:60:75

It seems to be trying to serialize an Error object to pass it from the worker to the main thread and fails.

When I resolve that bug by updating the extension source code to wrap the error object in a String() to make it serializable, I get the actual cause:

TypeError: Cannot read properties of undefined (reading 'forEach')
	at t.default.getSelectors (/Users/mak13180/Documents/code/code-portable-data/extensions/esbenp.prettier-vscode-11.0.2/dist/extension.js:640:19)
	at async t.default.handleActiveTextEditorChanged (/Users/mak13180/Documents/code/code-portable-data/extensions/esbenp.prettier-vscode-11.0.2/dist/extension.js:604:27)

Which happens here in the source code:

prettier-vscode/src/PrettierEditService.ts

Line 398 in 49528d4

languages.forEach((lang) => {

Operating System

macOS

VS Code Version

1.108.0

Prettier Extension Version

11.0.2

Prettier Version

3.8.0

Prettier Extension Logs

...

• Fixes DOMError when in PNPM package and using prettier plugin #3903

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[ntotten]

@Copolit we need to have a test case for this in our tests to validate the fix.