Prettier 3.x - Package subpath is not defined

[ivodolenc]

Hi, after updating prettier to 3.0.0, I am trying to set the main configuration from the shared configuration (npm package) but I'm getting errors via terminal:

["INFO" - 3:55:52 PM] Formatting file...
["ERROR" - 3:55:52 PM] Error resolving prettier configuration for ...
["ERROR" - 3:55:52 PM] Package subpath './prettier-base' is not defined by "exports" in .../node_modules/pkg/package.json

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './prettier-base' is not defined by "exports" in .../node_modules/pkg/package.json

Current pkg setup

node_modules/pkg/dist/prettier/prettier-base.mjs

export default {
  // ...
}

node_modules/pkg/package.json

{
  "type": "module",
  "exports": {
    "./prettier-base": {
      "types": "./dist/prettier/prettier-base.d.ts",
      "import": "./dist/prettier/prettier-base.mjs"
    }
  }
}

---

And later I import it into the project:

package.json

This throws the errors I mentioned above:

{
  "type": "module",
  "prettier": "pkg/prettier-base"
}

This works as expected without errors:

{
  "type": "module",
  "prettier": "./node_modules/pkg/dist/prettier/prettier-base.mjs"
}

and this also works as expected:

// prettier.config.js

import baseConfig from 'pkg/prettier-base'

export default baseConfig

Any advice?

[github-actions]

👋 @ivodolenc, we use the issue tracker exclusively for development purposes. For questions, please use Stack Overflow.

[ivodolenc]

Hi @kachkaev, may I ask why you closed this? Do I need you to share an example repo?

[kachkaev]

👋 @ivodolenc! I marked this issue as a question and it got automatically closed, according to this repo’s config. I believe that your issue is external to Prettier and is a generic one, related to configuring ESM modules.

Either way, it is hard to come up with advice without a full reproduction. You can try seeking for help on StackOverflow or in GitHub Discussions by sharing a repository or a code sandbox. Issues in this repo are dedicated to bug tracking and feature requests.

[ivodolenc]

I wrote "Any advice?" because maybe someone on the team already knows a quick fix or something... This is not a question but a bug report because the manual path from node_modules works as expected.

Also, when importing the configuration from the subpath into the custom prettier.config.js, that configuration works as expected (I've provided both examples above). Package subpaths works fine on my side.

It is possible that Pretier has problems finding node subpaths when the configuration is extended via package.json (prettier v3.x.x) but if you don't want to investigate further, I'm fine with that.

[kachkaev]

Looking at your terminal output, looks like this is an issue specific to VS Code. This repo is for tracking issues with Prettier core only. After a bit of digging, I think I found the issue report you are looking for: prettier/prettier-vscode#3066.

If you find a bug in Prettier core, please follow the issue template and make sure that there are reproduction steps that others can easily reproduce.

[ivodolenc]

Here is a minimal reproduction with a simple example. The npm package is live and you can also see the github repo with all the code.

[kachkaev]

Thanks for creating the reproduction repo @ivodolenc! Things make a bit more sense now. I was initially confused by patterns like ["INFO" - 3:55:52 PM] and ["ERROR" - 3:55:52 PM] in your issue report. They are often a sign of people having troubles with VS Code, which is external to this repo. Configuring ESM is often a bit tricky, so I thought this was a setup question of some sort. Existence of prettier/prettier-vscode#3066 confused me even more. Sorry for that!

Using the package you have published, I think I have been able to reproduce your steps in a terminal, outside VS Code:

cd /tmp

mkdir prettier-issue-15195
cd prettier-issue-15195

cat << EOF > package.json
{
  "type": "module",
  "prettier": "prettier-issue-test-config/prettier-base"
}
EOF

npm install --save-exact --save-dev prettier@3.0.0 prettier-issue-test-config@0.0.1

npx prettier --log-level=debug --write package.json

Output:

[debug] normalized argv: {"":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"logLevel":"debug","configPrecedence":"cli-override","debugRepeat":0,"ignorePath":[".gitignore",".prettierignore"],"plugins":[],"_":["package.json"],"__raw":{"_":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"log-level":"debug","config-precedence":"cli-override","debug-repeat":0,"ignore-path":[".gitignore",".prettierignore"],"plugin":[]}}
[debug] resolve config from '/private/tmp/prettier-issue-15195/package.json'
[error] Invalid configuration for file "/private/tmp/prettier-issue-15195/package.json":
[error] Package subpath './prettier-base' is not defined by "exports" in /private/tmp/prettier-issue-15195/node_modules/prettier-issue-test-config/package.json

Interestingly, when I make a somewhat illogical change to node_modules/prettier-issue-test-config/package.json, running npx prettier --log-level=debug --write package.json ends up working:

{
  "name": "prettier-issue-test-config",
  "version": "0.0.1",
  "license": "MIT",
  "type": "module",
  "exports": {
    "./prettier-base": {
+     "require": "./dist/prettier/prettier-base.mjs",
      "types": "./dist/prettier/prettier-base.d.ts",
      "import": "./dist/prettier/prettier-base.mjs"
    }
  },

[debug] normalized argv: {"":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"logLevel":"debug","configPrecedence":"cli-override","debugRepeat":0,"ignorePath":[".gitignore",".prettierignore"],"plugins":[],"_":["package.json"],"__raw":{"_":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"log-level":"debug","config-precedence":"cli-override","debug-repeat":0,"ignore-path":[".gitignore",".prettierignore"],"plugin":[]}}
[debug] resolve config from '/private/tmp/prettier-issue-15195/package.json'
[debug] loaded options `{"semi":false,"tabWidth":2,"singleQuote":true}`
[debug] applied config-precedence (cli-override): {"singleQuote":true,"semi":false,"tabWidth":2}
package.json 21ms

I tried removing "prettier": "prettier-issue-test-config/prettier-base", from package.json and creating .prettierrc.json with a reference to your package path:

"prettier-issue-test-config/prettier-base"

This also errored without the require exports hack:

[debug] normalized argv: {"":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"logLevel":"debug","configPrecedence":"cli-override","debugRepeat":0,"ignorePath":[".gitignore",".prettierignore"],"plugins":[],"_":["package.json"],"__raw":{"_":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"log-level":"debug","config-precedence":"cli-override","debug-repeat":0,"ignore-path":[".gitignore",".prettierignore"],"plugin":[]}}
[debug] resolve config from '/private/tmp/prettier-issue-15195/package.json'
[error] Invalid configuration for file "/private/tmp/prettier-issue-15195/package.json":
[error] Package subpath './prettier-base' is not defined by "exports" in /private/tmp/prettier-issue-15195/node_modules/prettier-issue-test-config/package.json

Finally, I replaced .prettierrc.json with prettier.config.js, similarly to what you did:

export { default } from "prettier-issue-test-config/prettier-base";

This worked:

[debug] normalized argv: {"":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"logLevel":"debug","configPrecedence":"cli-override","debugRepeat":0,"ignorePath":[".gitignore",".prettierignore"],"plugins":[],"_":["package.json"],"__raw":{"_":["package.json"],"cache":false,"color":true,"editorconfig":true,"write":true,"log-level":"debug","config-precedence":"cli-override","debug-repeat":0,"ignore-path":[".gitignore",".prettierignore"],"plugin":[]}}
[debug] resolve config from '/private/tmp/prettier-issue-15195/package.json'
[debug] loaded options `{"semi":false,"tabWidth":2,"singleQuote":true}`
[debug] applied config-precedence (cli-override): {"singleQuote":true,"semi":false,"tabWidth":2}
package.json 21ms

ESM support for config files was added in #13130. There are lots of test cases, but maybe we’ve found a gap? @fisker, WDYT?

@ivodolenc, thanks again for being persistent with this report, and apologies again for closing the issue too early!