Issue parsing .svelte files when using Flat Config

[eagerestwolf]

What version of eslint are you using?: 8.50.0

What version of prettier are you using?: 3.0.3

What version of eslint-plugin-prettier are you using?: 5.0.0

Please paste any applicable config files that you're using (e.g. .prettierrc or .eslintrc files)

prettier.config.js

/** @type {import("prettier").Config} */
export default {
  arrowParens: "always",
  bracketSameLine: true,
  bracketSpacing: true,
  endOfLine: "lf",
  htmlWhitespaceSensitivity: "css",
  overrides: [
    {
      files: "*svelte",
      options: {
        parser: "svelte"
      }
    }
  ],
  plugins: ["prettier-plugin-svelte", "prettier-plugin-tailwindcss"],
  printWidth: 100,
  proseWrap: "preserve",
  quoteProps: "as-needed",
  semi: true,
  singleAttributePerLine: false,
  singleQuote: false,
  svelteStrictMode: true,
  tabWidth: 2,
  trailingComma: "none",
  useTabs: false
};

eslint.config.js

For the sake of brevity, I didn't include all of my local includes and rules. This is an abbreviated version of the shared config I am using. Ignore the random trailing commas, I don't use trailing commas, but I copy and pasted parts of the shared config I use and VS Code insisted on putting in trailing commas.

import typescriptESLint from "@typescript-eslint/eslint-plugin";
import typescriptParser from "@typescript-eslint/parser";
import eslintConfigPrettier from "eslint-config-prettier";
import prettier from "eslint-plugin-prettier";
import svelte from "eslint-plugin-svelte";
import globals from "globals";
import svelteParser from "svelte-eslint-parser";

/** @type {import("eslint").Linter.FlatConfig[]} */
export default [
  {
    ignores: globalIgnores,
    languageOptions: {
      ecmaVersion: "latest",
    },
    linterOptions: {
      reportUnusedDisableDirectives: true,
    },
  },
  {
    ignores: globalIgnores,
    languageOptions: {
      ecmaVersion: "latest",
    },
    plugins: { prettier },
    rules: {
      ...prettier.configs.recommended.rules,
      "prettier/prettier": "error",
    },
  },
  {
    files: svelteFiles,
    ignores: svelteIgnores,
    languageOptions: {
      ecmaVersion: "latest",
      globals: {
        ...globals.browser,
        ...globals.es2017
      },
      parser: svelteParser,
      parserOptions: {
        extraFileExtensions: [".svelte"],
        parser: typescriptParser,
        project: "./tsconfig.json"
      }
    },
    plugins: {
      "@typescript-eslint": typescriptESLint,
      svelte
    },
    rules: {
      ...baseRules,
      ...typescriptBaseRules,
      ...typescriptOverrideRules,
      ...svelteRules
    }
  },
  {
    files: javascriptFiles,
    ignores: javascriptIgnores,
    languageOptions: {
      globals: {
        ...globals.es2017,
        ...globals.node
      }
    },
    rules: {
      ...baseRules,
      ...javascriptRules
    }
  },
  {
    files: typescriptFiles,
    ignores: typescriptIgnores,
    languageOptions: {
      ecmaVersion: "latest",
      globals: { ...globals.es2017, ...globals.node },
      parser: typescriptParser,
      parserOptions: {
        extraFileExtensions: [".svelte"],
        project: "./tsconfig.json"
      }
    },
    plugins: {
      "@typescript-eslint": typescriptESLint
    },
    rules: {
      ...baseRules,
      ...typescriptBaseRules,
      ...typescriptOverrideRules
    }
  },
  eslintConfigPrettier,
  {
    languageOptions: {
      parserOptions: {
        project: "./tsconfig.node.json"
      }
    }
  }
];

If you wish to see my actual eslint.config.js, this is it

import { garavest } from "@garavest/eslint-config";

/** @type {import("eslint").Linter.FlatConfig[]} */
export default [
  ...garavest.default,
  {
    languageOptions: {
      parserOptions: {
        project: "./tsconfig.node.json"
      }
    }
  }
];

What source code are you linting?

.svelte files in a SvelteKit project.

What did you expect to happen?

I expected to get a report of any code format issues in my code base.

What actually happened?

I got an error from ESLint :(

website on  main [✘!?] via  v18.17.1 took 17s
❯ pnpm eslint .

Oops! Something went wrong! :(

ESLint: 8.50.0

TypeError: Cannot read properties of undefined (reading 'includes')
    at C:\Users\Seth Murphy\sources\website\node_modules\.pnpm\eslint-plugin-prettier@5.0.0_eslint-config-prettier@9.0.0_eslint@8.50.0_prettier@3.0.3\node_modules\eslint-plugin-prettier\worker.js:115:27

Crazy thing is, I don't know why this error is being thrown. The plugin is reading context.parserPath which is correct for a flat config. For reference, this is the line that is causing the error. Everything else works fine, but then again Svelte is the only case I have where this plugin specifically needs to check which parser is used. I know ESLint is reading the config correctly because everything else works fine, just not this. If I change the config to remove Prettier, everything is fine. I'm kinda stumped, but I don't know much about creating ESLint plugins.

I now know the issue. Everyone say it with me now..."Flat Config". Ugh. I hate paying the early adopter tax sometimes. I don't really know how to get around this one either. I guess, I'll just have to tell this plugin to avoid .svelte files for the time being.

[JounQin]

close in favor of #588