Turn off problematic rules in recommended config (prepare for next es…

…lint-config-prettier version) (#360)

README.md

@@ -2,6 +2,8 @@
 
 Runs [Prettier](https://github.com/prettier/prettier) as an [ESLint](http://eslint.org) rule and reports differences as individual ESLint issues.
 
+If your desired formatting does not match Prettier’s output, you should use a different tool such as [prettier-eslint](https://github.com/prettier/prettier-eslint) instead.
+
 ## Sample
 
 ```js
@@ -52,48 +54,68 @@ Then, in your `.eslintrc.json`:
 
 ## Recommended Configuration
 
-This plugin works best if you disable all other ESLint rules relating to code formatting, and only enable rules that detect patterns in the AST. (If another active ESLint rule disagrees with `prettier` about how code should be formatted, it will be impossible to avoid lint errors.) You can use [eslint-config-prettier](https://github.com/prettier/eslint-config-prettier) to disable all formatting-related ESLint rules.
-
-If your desired formatting does not match the `prettier` output, you should use a different tool such as [prettier-eslint](https://github.com/prettier/prettier-eslint) instead.
+This plugin works best if you disable all other ESLint rules relating to code formatting, and only enable rules that detect potential bugs. (If another active ESLint rule disagrees with `prettier` about how code should be formatted, it will be impossible to avoid lint errors.) You can use [eslint-config-prettier](https://github.com/prettier/eslint-config-prettier) to disable all formatting-related ESLint rules.
 
-To integrate this plugin with `eslint-config-prettier`, you can use the `"recommended"` configuration:
+This plugin ships with a `plugin:prettier/recommended` config that sets up both the plugin and `eslint-config-prettier` in one go.
 
 1. In addition to the above installation instructions, install `eslint-config-prettier`:
 
    ```sh
    npm install --save-dev eslint-config-prettier
    ```
 
-2. Then you need to add `plugin:prettier/recommended` as the last extension in your `.eslintrc.json`:
+2. Then you need to add `plugin:prettier/recommended` as the _last_ extension in your `.eslintrc.json`:
 
    ```json
    {
      "extends": ["plugin:prettier/recommended"]
    }
    ```
 
-This does three things:
+   You can then set Prettier's own options inside a `.prettierrc` file.
 
-- Enables `eslint-plugin-prettier`.
-- Sets the `prettier/prettier` rule to `"error"`.
-- Extends the `eslint-config-prettier` configuration.
+3. Some ESLint plugins (such as [eslint-plugin-react](https://github.com/yannickcr/eslint-plugin-react)) also contain rules that conflict with Prettier. Add extra exclusions for the plugins you use like so:
+
+   ```json
+   {
+     "extends": [
+       "plugin:prettier/recommended",
+       "prettier/flowtype",
+       "prettier/react"
+     ]
+   }
+   ```
 
-You can then set Prettier's own options inside a `.prettierrc` file.
+   For the list of every available exclusion rule set, please see the [readme of eslint-config-prettier](https://github.com/prettier/eslint-config-prettier/blob/master/README.md).
 
-3. In order to support special ESLint plugins (e.g. [eslint-plugin-react](https://github.com/yannickcr/eslint-plugin-react)), add extra exclusions for the plugins you use like so:
+Exactly what does `plugin:prettier/recommended` do? Well, this is what it expands to:
 
 ```json
 {
-  "extends": [
-    "plugin:prettier/recommended",
-    "prettier/flowtype",
-    "prettier/react",
-    "prettier/standard"
-  ]
+  "extends": ["prettier"],
+  "plugins": ["prettier"],
+  "rules": {
+    "prettier/prettier": "error",
+    "arrow-body-style": "off",
+    "prefer-arrow-callback": "off"
+  }
 }
 ```
 
-For the list of every available exclusion rule set, please see the [readme of eslint-config-prettier](https://github.com/prettier/eslint-config-prettier/blob/master/README.md).
+- `"extends": ["prettier"]` enables the main config from `eslint-config-prettier`, which turns off some ESLint core rules that conflict with Prettier.
+- `"plugins": ["prettier"]` registers this plugin.
+- `"prettier/prettier": "error"` turns on the rule provided by this plugin, which runs Prettier from within ESLint.
+- `"arrow-body-style": "off"` and `"prefer-arrow-callback": "off"` turns off two ESLint core rules that unfortunately are problematic with this plugin – see the next section.
+
+## `arrow-body-style` and `prefer-arrow-callback` issue
+
+If you use [arrow-body-style](https://eslint.org/docs/rules/arrow-body-style) or [prefer-arrow-callback](https://eslint.org/docs/rules/prefer-arrow-callback) together with the `prettier/prettier` rule from this plugin, you can in some cases end up with invalid code due to a bug in ESLint’s autofix – see [issue #65](https://github.com/prettier/eslint-plugin-prettier/issues/65).
+
+For this reason, it’s recommended to turn off these rules. The `plugin:prettier/recommended` config does that for you.
+
+You _can_ still use these rules together with this plugin if you want, because the bug does not occur _all the time._ But if you do, you need to keep in mind that you might end up with invalid code, where you manually have to insert a missing closing parenthesis to get going again.
+
+If you’re fixing large of amounts of previously unformatted code, consider temporarily disabling the `prettier/prettier` rule and running `eslint --fix` and `prettier --write` separately.
 
 ## Options
 

eslint-plugin-prettier.js

@@ -110,7 +110,9 @@ module.exports = {
       extends: ['prettier'],
       plugins: ['prettier'],
       rules: {
-        'prettier/prettier': 'error'
+        'prettier/prettier': 'error',
+        'arrow-body-style': 'off',
+        'prefer-arrow-callback': 'off'
       }
     }
   },