Extension can't use plugin object (CLI can; Extension can use plugin's path/name string)

[tomchen]

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Summary

Extension shows error while CLI is good with a local custom plugin.

Edit: it seems Extension can't use a imported plugin configuration object (but CLI can). Extension can only use plugin's path/name string

Steps To Reproduce:

• New folder, npm init -y, latest VS Code, install latest Prettier extension and set it as default JS formatter, prettier not installed globally with npm
• npm install -D prettier
• Add ./prettier.config.mjs:

import customPlugin from "./prettier-plugin-custom.mjs";

export default {
  plugins: [customPlugin],
};

• Add ./prettier-plugin-custom.mjs:

import { parsers as parsersBabel } from "prettier/plugins/babel";

export default {
  parsers: {
    babel: parsersBabel.babel,
  },
};

• npx prettier --write prettier-plugin-custom.mjs -> No problem
• Shift + Alt + F to format prettier-plugin-custom.mjs -> Error, log simply shows Invalid prettier configuration file detected. See log for details.

Additional information

VS Code Version:

Latest

Version: 1.98.0 (user setup)
Commit: 6609ac3d66f4eade5cf376d1cb76f13985724bcb
Date: 2025-03-04T21:06:18.612Z
Electron: 34.2.0
ElectronBuildId: 11044223
Chromium: 132.0.6834.196
Node.js: 20.18.2
V8: 13.2.152.36-electron.0
OS: Windows_NT x64 10.0.26100

Prettier Extension Version: Latest 11.0.0

OS and version: Windows 11

Prettier Log Output

Simply

Invalid prettier configuration file detected. See log for details.

I don't see any details

Further attempts

I changed Node.js from v22.13.1 to v20.18.2 with nvm to align with VS Code Electron's Node version to see if it is caused by that, but CLI is still good.

I changed the files to Common JS:

prettier.config.cjs

const customPlugin = require("./prettier-plugin-custom.cjs");

module.exports = {
  plugins: [customPlugin],
};

prettier-plugin-custom.cjs

const { parsers: parsersBabel } = require("prettier/parser-babel");

module.exports = {
  parsers: {
    babel: parsersBabel.babel,
  },
};

Still CLI good extension bad

[SystemParadox]

Invalid prettier configuration file detected. See log for details.

This is the most frustrating thing about this issue - there is no log that shows anything other than this message. Combined with the fact that it works fine on the command line it makes this completely impossible to debug.

[SystemParadox]

Help -> Toggle developer tools in vscode may be helpful. This at least lets me see console.log statements in the prettier file. In my case the prettierrc is loading fine, so I think it's something in prettier or this plugin that then throws for some reason?

Changing to use plugins: ['prettier-plugin-svelte'] rather than plugins: [ require('prettier-plugin-svelte') ] seems to fix it which is odd. Does prettier not allow loading plugins like this anymore? But then why does it work on the CLI?

[kingston]

It appears related to https://github.com/prettier/prettier/discussions/15167 so potentially something to do with RPC boundaries and the fact that required modules cannot be sent to the appropriate worker thread.

I was able to workaround it with:

import url from 'node:url';

export default {
  ...,
  plugins: [
    url.fileURLToPath(import.meta.resolve('prettier-plugin-packagejson')),
  ]
}

But the simple string works too if it's in the root node_modules (I'm using a monorepo approach with PNPM which does not hoist plugins by default anymore)

[SystemParadox]

We're also using pnpm but we've added public-hoist-pattern[]='prettier-plugin-svelte' to .npmrc to hoist it.

The fileURLToPath example is useful though, I might try that instead.

[tomchen]

OK. Updated the title and summary

[github-actions[bot]]

This issue has been labeled as stale due to inactivity. Reply to keep this issue open.

[SystemParadox]

Even if this isn't something that prettier-vscode can fix, it does at least need documenting.