Report deprecated rules that are in use

[randycoulman]

In addition to #172, which would keep eslint-find-rules from reporting errors when deprecated rules are unused, it might also be nice to have a command-line option that shows deprecated rules that are still being used in a configuration.

[randycoulman]

I've been thinking more about this as I think about implementing it, and I realize that eslint already warns when deprecated rules are in use. Is this feature useful enough to implement here anyway? Or should I just close the issue?

[ljharb]

I think it's still useful to get a zero/nonzero exit code based on the config files, without having to actually run eslint.

[randycoulman]

Yeah, good point. I'll keep it open and work on it when I get a chance.

[alexilyaev]

ESLint doesn't warn when using deprecated rules in the config, only when using rules that don't exist anymore.

I've got 2 deprecated rules here: https://github.com/alexilyaev/react-es6-starter
newline-after-var and newline-before-return
Running eslint -c .eslintrc --ignore-path .gitignore . doesn't show me any warning.

I think an option to show currently configured deprecated rules is very useful.
We actually have no way of checking it right now

I'm doing something similar with stylelint-find-rules.
Can show configured deprecated rules.

Just tried filtering the currentRules:

  this.getCurrentDeprecatedRules = function () {
    var rules = eslint.linter.getRules();

    return getSortedRules(currentRules).filter(function (rule) {
      return _isDeprecated(rules.get(rule) || '')
    });
  };

It worked, though if I have extends, it counts rules from them as well.
Perhaps ignore extends somehow.

[ta2edchimp]

A flag to ignore a config's "extends" would be nice.
But atm, only manipulating the input (removing the "extends" property of the config to be loaded) before actually loading the configuration via ESLint's CLIEngine comes to my mind.

[alexilyaev]

@ta2edchimp @randycoulman So, after 2 years, I find myself back here :-)

I'm trying to validate user configured rules to not have deprecated rules.
This is useful when upgrading configs/plugins which deprecate certain rules.

Right now running eslint-find-rules -d .eslintrc will show deprecated rules not only from user configured rules, but also from extends.

I dug into the code and found it's not so simple to mitigate.
At _getConfigs we use cliEngine.getConfigForFile which loads the configFile and merges all extends on top of it.
Which means that currentRuleNames will already include rules from extends and not only the user defined rules.
And then deprecatedRuleNames can show rules that were not defined by the user.

This happened to me with eslint-config-prettier:
prettier/eslint-config-prettier#112

I tried to dig into eslint's CLIEngine code as well.
Looks like there's a cascade of configs that are being loaded and merged under CascadingConfigArrayFactory.
But eventually our configFile is loaded with configArrayFactory.loadFile, which runs _normalizeConfigData, which then loads and merges the extends and other things.

The only thing I came up with is this:

const { ConfigArrayFactory } = require('eslint/lib/cli-engine/config-array-factory.js');
const configArrayFactory = new ConfigArrayFactory();
configArrayFactory.loadFile(configFile, { name: "UserConfig" });

Which gives us an Array of configs... the user config, extends, overrides, etc.
From here it might be possible to filter out the extends and get a merged config only from user defined rules.

Here's how it looks like

[
  { name:
     'UserConfig » eslint-config-ai/react » eslint-config-prettier/react',
    filePath:
     '/Users/alex/www/Node/Personal/eslint-config-ai/node_modules/eslint-config-prettier/react.js',
    criteria: null,
    env: undefined,
    globals: undefined,
    noInlineConfig: undefined,
    parser: undefined,
    parserOptions: undefined,
    plugins: undefined,
    processor: undefined,
    reportUnusedDisableDirectives: undefined,
    root: undefined,
    rules:
     { 'react/jsx-child-element-spacing': 'off',
       'react/jsx-closing-bracket-location': 'off',
       'react/jsx-closing-tag-location': 'off',
       'react/jsx-curly-newline': 'off',
       'react/jsx-curly-spacing': 'off',
       'react/jsx-equals-spacing': 'off',
       'react/jsx-first-prop-new-line': 'off',
       'react/jsx-indent': 'off',
       'react/jsx-indent-props': 'off',
       'react/jsx-max-props-per-line': 'off',
       'react/jsx-one-expression-per-line': 'off',
       'react/jsx-props-no-multi-spaces': 'off',
       'react/jsx-space-before-closing': 'off',
       'react/jsx-tag-spacing': 'off',
       'react/jsx-wrap-multilines': 'off' },
    settings: undefined },
  { name: 'UserConfig » eslint-config-ai/react',
    filePath: '/Users/alex/www/Node/Personal/eslint-config-ai/react.js',
    criteria: null,
    env: { es6: true },
    globals: undefined,
    noInlineConfig: undefined,
    parser:
     { error: null,
       filePath:
        '/Users/alex/www/Node/Personal/eslint-config-ai/node_modules/babel-eslint/lib/index.js',
       id: 'babel-eslint',
       importerName: 'UserConfig » eslint-config-ai/react',
       importerPath: '/Users/alex/www/Node/Personal/eslint-config-ai/react.js' },
    parserOptions:
     { ecmaVersion: 6, ecmaFeatures: [Object], sourceType: 'script' },
    plugins: { react: [Object], compat: [Object] },
    processor: undefined,
    reportUnusedDisableDirectives: undefined,
    root: undefined,
    rules: { 'compat/compat': 1, 'react/jsx-pascal-case': 1 },
    settings: { react: [Object] } },
  { name: 'UserConfig » eslint-config-ai/react#overrides[0]',
    filePath: '/Users/alex/www/Node/Personal/eslint-config-ai/react.js',
    criteria:
     { includes: [Array],
       excludes: null,
       basePath: '/Users/alex/www/Node/Personal/eslint-config-ai' },
    env: { browser: true, node: false },
    globals: { process: true, module: true },
    noInlineConfig: undefined,
    parser: undefined,
    parserOptions: { sourceType: 'module' },
    plugins: undefined,
    processor: undefined,
    reportUnusedDisableDirectives: undefined,
    root: undefined,
    rules: { strict: [Array] },
    settings: undefined },
  { name: 'UserConfig',
    filePath: '/Users/alex/www/Node/Personal/eslint-config-ai/.eslintrc',
    criteria: null,
    env: undefined,
    globals: undefined,
    noInlineConfig: undefined,
    parser: undefined,
    parserOptions: undefined,
    plugins: undefined,
    processor: undefined,
    reportUnusedDisableDirectives: undefined,
    root: true,
    rules: {},
    settings: undefined }
]