From ea6a2171a03e65efe9842bbf75e33722cab0cf5e Mon Sep 17 00:00:00 2001
From: Haoqun Jiang <haoqunjiang@gmail.com>
Date: Fri, 19 Apr 2019 21:37:39 +0800
Subject: [PATCH] feat: require ESLint as a peer dependency

BREAKING CHANGE:
Users will have to explicitly list their required ESLint version in the
project's package.json.

The major concern behind this change is that ESLint release schedule is
never aligned with Vue CLI's.
See https://eslint.org/blog/2019/04/eslint-v6.0.0-alpha.0-released
So even if we upgraded our built-in ESLint version to v5, we'll see a
new major release of ESLint in the coming months. Meanwhile we can't
easily upgrade the built-in ESLint version again without bumping our
major version number. This could become a maintenance nightmare.
---
 packages/@vue/cli-plugin-eslint/generator/index.js |  9 ++++++++-
 packages/@vue/cli-plugin-eslint/index.js           | 12 ++++--------
 packages/@vue/cli-plugin-eslint/package.json       |  6 +++---
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/packages/@vue/cli-plugin-eslint/generator/index.js b/packages/@vue/cli-plugin-eslint/generator/index.js
index 5dd53318b5..fde6c18d80 100644
--- a/packages/@vue/cli-plugin-eslint/generator/index.js
+++ b/packages/@vue/cli-plugin-eslint/generator/index.js
@@ -13,7 +13,14 @@ module.exports = (api, { config, lintOn = [] }, _, invoking) => {
       lint: 'vue-cli-service lint'
     },
     eslintConfig,
-    devDependencies: {}
+    devDependencies: {
+      'eslint': '^5.16.0',
+      'eslint-plugin-vue': '^5.0.0'
+    }
+  }
+
+  if (!api.hasPlugin('typescript')) {
+    pkg.devDependencies['babel-eslint'] = '^10.0.1'
   }
 
   const injectEditorConfig = (config) => {
diff --git a/packages/@vue/cli-plugin-eslint/index.js b/packages/@vue/cli-plugin-eslint/index.js
index bd109efe9a..959a8fb67c 100644
--- a/packages/@vue/cli-plugin-eslint/index.js
+++ b/packages/@vue/cli-plugin-eslint/index.js
@@ -6,9 +6,7 @@ module.exports = (api, options) => {
     // Use loadModule to allow users to customize their ESLint dependency version.
     const { resolveModule, loadModule } = require('@vue/cli-shared-utils')
     const cwd = api.getCwd()
-    const eslintPkg =
-      loadModule('eslint/package.json', cwd, true) ||
-      require('eslint/package.json')
+    const eslintPkg = loadModule('eslint/package.json', cwd, true)
 
     // eslint-loader doesn't bust cache when eslint config changes
     // so we have to manually generate a cache identifier that takes the config
@@ -37,7 +35,7 @@ module.exports = (api, options) => {
           .pre()
           .exclude
             .add(/node_modules/)
-            .add(require('path').dirname(require.resolve('@vue/cli-service')))
+            .add(path.dirname(require.resolve('@vue/cli-service')))
             .end()
           .test(/\.(vue|(j|t)sx?)$/)
           .use('eslint-loader')
@@ -48,10 +46,8 @@ module.exports = (api, options) => {
               cacheIdentifier,
               emitWarning: options.lintOnSave !== 'error',
               emitError: options.lintOnSave === 'error',
-              eslintPath: resolveModule('eslint', cwd) || require.resolve('eslint'),
-              formatter:
-                loadModule('eslint/lib/formatters/codeframe', cwd, true) ||
-                require('eslint/lib/formatters/codeframe')
+              eslintPath: resolveModule('eslint', cwd),
+              formatter: loadModule('eslint/lib/formatters/codeframe', cwd, true)
             })
     })
   }
diff --git a/packages/@vue/cli-plugin-eslint/package.json b/packages/@vue/cli-plugin-eslint/package.json
index b55d7e54d6..ac2e0c62f7 100644
--- a/packages/@vue/cli-plugin-eslint/package.json
+++ b/packages/@vue/cli-plugin-eslint/package.json
@@ -24,11 +24,11 @@
   },
   "dependencies": {
     "@vue/cli-shared-utils": "^3.5.1",
-    "babel-eslint": "^10.0.1",
-    "eslint": "^5.8.0",
     "eslint-loader": "^2.1.2",
-    "eslint-plugin-vue": "^5.0.0",
     "globby": "^9.0.0",
     "webpack": ">=4 < 4.29"
+  },
+  "peerDependencies": {
+    "eslint": ">= 1.6.0"
   }
 }