ESLint couldn't determine the plugin uniquely.

[MaximeBernard]

I'm trying to upgrade to eslint@7.1.0 but some breaking changes in the plugin resolution seems to get in the way.
I'm using a monorepo with yarn workspaces and the noHoist setting.
My current tree looks like this

package.json
.eslintrc
node_modules/
packages/
   app/
      .eslintrc
      package.json
      node_modules/
   api/
      .eslintrc
      package.json
      node_modules/

but when I run yarn workspace app lint

$ eslint src/**.ts*

Oops! Something went wrong! :(

ESLint: 7.0.0

ESLint couldn't determine the plugin "prettier" uniquely.

- /myproject/packages/app/node_modules/eslint-plugin-prettier/eslint-plugin-prettier.js (loaded in ".eslintrc » ../../.eslintrc")
- /myproject/node_modules/eslint-plugin-prettier/eslint-plugin-prettier.js (loaded in "../../.eslintrc")

Please remove the "plugins" setting from either config or remove either plugin installation.

My packages .eslintrc configuration files are just

{
  "extends": ["../../.eslintrc"]
}

which are supposed to help us load specific plugins per package (i.e. eslint-plugin-react for app, not for api)

Any idea where to go from here?
I posted my issue on Gitter and someone suggested to use --resolve-plugins-relative-to but so far, eslint --resolve-plugins-relative-to ./packages/app src/**.ts* and eslint --resolve-plugins-relative-to ./packages/app src/**.ts* still look in the ROOT node_modules. Am I missing something?
Bonus question for my curiosity: why eslint@7 wants uniqueness so badly?

Tell us about your environment

• yarn v1.22.4
• working ESLint: 6.8.0

./node_modules/.bin/eslint --env-info
Environment Info:

Node version: v14.3.0
npm version: v6.14.4
Local ESLint version: Not found
Global ESLint version: Not found

• not-working ESLint: 7.0.0 & 7.1.0

Please show your full configuration:

Root .eslintrc

{
  "env": {
    "browser": true,
    "es6": true
  },
  "globals": {
    "Atomics": "readonly",
    "SharedArrayBuffer": "readonly"
  },
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "project": ["./tsconfig.json"],
    "ecmaFeatures": {
      "jsx": true
    },
    "ecmaVersion": 2018,
    "sourceType": "module"
  },
  "settings": {
    "react": {
      "version": "detect"
    }
  },
  "plugins": [
    "prettier",
    "jest",
    "@typescript-eslint",
    "import",
    "react",
    "react-hooks",
    "functional"
  ],
  "extends": [
    "eslint:recommended",
    "prettier",
    "plugin:jest/recommended",
    "plugin:prettier/recommended",
    "plugin:import/errors",
    "plugin:import/warnings",
    "plugin:import/typescript",
    "plugin:react/recommended",
    "plugin:@typescript-eslint/eslint-recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:@typescript-eslint/recommended-requiring-type-checking",
    "plugin:functional/external-recommended",
    "plugin:functional/recommended"
  ],
  "rules": {
    "prettier/prettier": "error",
    "react-hooks/rules-of-hooks": "error",
    "react-hooks/exhaustive-deps": "warn",

    "react/no-this-in-sfc": "error",
    "react/prefer-stateless-function": "error",
    "react/jsx-pascal-case": "error",

    "@typescript-eslint/array-type": "error",
    "@typescript-eslint/no-dynamic-delete": "error",
    "@typescript-eslint/no-extra-non-null-assertion": "error",
    "@typescript-eslint/no-non-null-asserted-optional-chain": "error",
    "@typescript-eslint/no-require-imports": "error",
    "@typescript-eslint/no-unnecessary-boolean-literal-compare": "error",
    "@typescript-eslint/no-unnecessary-condition": "error",
    "@typescript-eslint/no-unnecessary-qualifier": "error",
    "@typescript-eslint/no-unnecessary-type-arguments": "error",
    "@typescript-eslint/no-unnecessary-type-assertion": "error",
    "@typescript-eslint/prefer-as-const": "error",
    "@typescript-eslint/prefer-for-of": "error",
    "@typescript-eslint/prefer-includes": "error",
    "@typescript-eslint/prefer-optional-chain": "error",
    "@typescript-eslint/promise-function-async": "error",
    "@typescript-eslint/restrict-plus-operands": "error",
    "@typescript-eslint/restrict-template-expressions": "error",
    "@typescript-eslint/strict-boolean-expressions": "error",
    "@typescript-eslint/switch-exhaustiveness-check": "error",
    "@typescript-eslint/default-param-last": "error",
    "@typescript-eslint/no-array-constructor": "error",
    "@typescript-eslint/no-dupe-class-members": "error",
    "@typescript-eslint/no-empty-function": "error",
    "@typescript-eslint/no-use-before-define": "error",
    "@typescript-eslint/no-useless-constructor": "error",
    "@typescript-eslint/no-unused-vars": "error",
    "@typescript-eslint/require-await": "error",
    "@typescript-eslint/return-await": "error",

    "import/first": "error",
    "import/order": [
      "error",
      {
        "groups": [
          "index",
          "sibling",
          "parent",
          "internal",
          "external",
          "builtin"
        ],
        "newlines-between": "never",
        "alphabetize": {
          "order": "asc"
        }
      }
    ],
    "import/no-default-export": "error",
    "import/no-unused-modules": ["warn", { "unusedExports": true }],

    "functional/no-expression-statement": [
      "error",
      {
        // Ignored for Jest usage: "test" & "expect"
        // Ingored for React usage: "ReactDOM", "set*" (hooks)
        "ignorePattern": ["test", "expect", "ReactDOM", "set*"]
      }
    ],
    "functional/functional-parameters": "off" // in React & Jest, too many things work without parameters
  }
}

Children .eslintrc

``` { "extends": ["../../.eslintrc"] } ```

[kwv]

Similar issue. My app/ creates scaffolding (e.g. downstream) as part of an integration test.

app/
  .eslintrc
  package.json
  node_modules/
  downstream/
      .eslintrc
      package.json
      node_modules/

adding --resolve-plugins-relative-to . to the downstream .eslintrc addressed the issue

[mysticatea]

@MaximeBernard ESLint loads all config files from the ancestor directories of lint target files. Then, ESLint 7.x loads plugins from the location of each config file which has the plugins field. (On the other hand, ESLint 6.x loads all plugins from the current working directory.)

In your case, I guess it's solved if you add root: true into your config file. It stops ESLint loading other config files from ancestor directories than the config file.

(currently, it loads .eslintrc twice because packages/*/.eslintrc extends it and ESLint loads config files from ancestor directories. It looks extra a bit, and root:true will improve it.)

[MaximeBernard]

Works perfectly, thank you @mysticatea 👍

[MaximeBernard]

May I suggest to add some documentation about this in https://eslint.org/docs/developer-guide/shareable-configs ?

[kaicataldo]

PRs to update documentation are welcome!

[MaximeBernard]

To be honest, I thought about it but I don't fully understand how it works so I don't feel like the right person to do it...

Or maybe you could point me to the right direction (the part in the code that handle that root: true) so I can read it and reverse engineer it?

[j1i-ian]

on 7.2.0 package "import" has conflicts, and is not working specifying root in eslinrc.js

I could fixing with --resolve-plugins-relative-to . option. Thank you @kwv !