Eslint-plugin-vue: Beta incorrectly flags rule valid-template-root for pug templates

[prograhammer]

Tell us about your environment
Ubuntu 16.04 Gnome 3

• ESLint Version:
  3.19.0
• eslint-plugin-vue Version:
  beta (v3.12.0)
• Node Version:
  6.11.0

Please show your full configuration:

// http://eslint.org/docs/user-guide/configuring

module.exports = {
  root: true,
  parserOptions: {
    parser: 'babel-eslint',
    sourceType: 'module'
  },
  env: {
    browser: true,
  },
  // https://github.com/feross/standard/blob/master/RULES.md#javascript-standard-style
  // https://github.com/vuejs/eslint-plugin-vue
  extends: [
    'standard',
    'plugin:vue/recommended'
  ],
  // required to lint *.vue files
  plugins: [
    'html'
  ],
  'settings': {
      'html/html-extensions': ['.html'],  // don't include .vue
  },
  // add your custom rules here
  'rules': {
    // allow paren-less arrow functions
    'arrow-parens': 0,
    // allow async-await
    'generator-star-spacing': 0,
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 2 : 0
  }
}

What did you do? Please include the actual source code causing the issue.

<template lang="pug">
.example
  | blah blah blah
</template>

<script>
export default {
  data () {
    return {

    }
  }
}
</script>

What did you expect to happen?
When I had beta v3.8.0, no linter errors occurred. After beta v3.9.0 and above, the linter error occurs in all pug templates: valid-template-root.

What actually happened? Please include the actual, raw output from ESLint.
I get an valid-template-root error for all my pug templates. It seems the latest beta updates now think that the root element is text when it is actually valid pug markup.

[armano2]

@prograhammer for now eslint-plugin-vue supports only html -> https://github.com/mysticatea/vue-eslint-parser

i think we should consider adding check if type set as lang is set to "html" or not set at all

[mysticatea]

Thank you for this report.

Yes, vue-eslint-parser has not support PUG yet.
This is a bug of vue-eslint-parser.
ast.templateBody should be undefined if the <template> is not HTML. But it exists as one Text node currently.

[Aysnine]

Now, pug is still not being ignored.

{
  "name": "xxx",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "build:preview": "vue-cli-service build --report --mode=preview",
    "lint": "vue-cli-service lint"
  },
  "dependencies": {
    "axios": "^0.18.0",
    "mockjs": "^1.0.1-beta3",
    "vue": "^2.5.17",
    "vuex": "^3.0.1"
  },
  "devDependencies": {
    "@vue/cli-plugin-babel": "^3.1.0",
    "@vue/cli-plugin-eslint": "^3.1.0",
    "@vue/cli-service": "^3.1.0",
    "@vue/eslint-config-prettier": "^4.0.0",
    "babel-eslint": "^10.0.1",
    "eslint": "^5.8.0",
    "eslint-plugin-vue": "^5.0.0-0",
    "pug": "^2.0.3",
    "pug-plain-loader": "^1.0.0",
    "stylus": "^0.54.5",
    "stylus-loader": "^3.0.2",
    "vue-template-compiler": "^2.5.17"
  },
  "eslintConfig": {
    "root": true,
    "env": {
      "node": true
    },
    "extends": [
      "plugin:vue/essential",
      "@vue/prettier"
    ],
    "rules": {
      "prettier/prettier": [
        "warn",
        {
          "singleQuote": true,
          "semi": false,
          "trailingComma": "none"
        }
      ]
    },
    "parserOptions": {
      "parser": "babel-eslint"
    }
  },
  "postcss": {
    "plugins": {
      "autoprefixer": {}
    }
  },
  "browserslist": [
    "> 1%",
    "last 2 versions",
    "not ie <= 8"
  ]
}