eslint: Refactor eslint-loader and eslintrc config generation #1182
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| ### Information | ||
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| If you want your preset or middleware to also extend from another **ESLint configuration or preset** that you have made |
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This is now covered by all of the defaults above being listed under baseConfig instead
| a dependency, you must use `baseConfig.extends` rather than just `extends`. This is a limitation of ESLint, not this | ||
| middleware. | ||
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| ### Override configuration |
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This section is unnecessary IMO (given most people should not be using this method of customisation), and given the pain points we see around lint configuration, I think we need to take a strict "less is more" approach to what we put in the docs for it.
| @@ -168,64 +168,26 @@ module.exports = { | |||
| use: [ | |||
| ['@neutrinojs/airbnb-base', { | |||
| eslint: { | |||
| rules: { | |||
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It's worth noting that this form still works, it's just not what we're using for the defaults / what we're recommending. Any preset that pass in the old form will still correctly override the values under baseConfig, since ESLint's CLIEngine (plus our eslintrc conversion function) merges them in such a way that the top-level options take precedence.
| ], | ||
| 'babel/no-invalid-this': 'off', | ||
| 'babel/no-unused-expressions': [ | ||
| 'warn', |
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This case is an example of one of the tests that would have failed previously - since before the resultant config would have discarded the rule settings, and just had the value of 'warn'.
| @@ -42,68 +42,53 @@ const eslint = require('@neutrinojs/eslint'); | |||
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| // Usage shows default values | |||
| neutrino.use(eslint, { | |||
| test: neutrino.regexFromExtensions(), // Uses extensions from neutrino.options.extensions | |||
| // Uses extensions from neutrino.options.extensions | |||
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I've adjusted the wrapping here so the code block in the docs doesn't need to have horizontal scroll bars.
| env: { | ||
| es6: true | ||
| }, | ||
| extends: [], |
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I've deliberately included empty config options here to give hints (both in the docs and via --inspect) as to where the correct place is to pass each of the options.
| const { ConfigurationError, DuplicateRuleError } = require('neutrino/errors'); | ||
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| const merge = (source, destination) => { |
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This old merge function missed several cases:
- it didn't apply the rule-merge to
baseConfig.rules - the rule-merge doesn't keep the settings of the old rule, when wanting to just adjust the off/warn/error level (unlike eslint's own merge)
- it doesn't merge
overridescorrectly
See these testcases:
https://github.com/eslint/eslint/blob/5984820670c3085becc98b75827fc4899001e605/tests/lib/config/config-ops.js#L305-L319
https://github.com/eslint/eslint/blob/5984820670c3085becc98b75827fc4899001e605/tests/lib/config/config-ops.js#L481-L494
| : merge(lintOptions, { | ||
| baseConfig: { | ||
| env: { | ||
| 'jest/globals': true |
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I've converted the top-level envs array form to the object form under baseConfig.env, since:
- users will be more familiar with it (ref Linting issue with neutrino v9 #1166 (comment))
- it then means it's possible to override an
envby passing eg'jest/globals': false(with arrays manual filtering would have to be performed) - it means the resultant
--inspectoutput is much closer to a form that can be copy-pasted into an.eslintrc.*file
* Adds option validation to `@neutrinojs/eslint`, so that it now throws when passed options that are not supported by eslint-loader. * The eslintrc conversion now correctly handles all supported options under `baseConfig` rather than silently ignoring them. * The eslintrc conversion no longer looks for settings in locations that are invalid for eslint-loader (such as top-level `settings`, `extends`, `root` or `overrides` options). * The eslintrc conversion now no longer errors if passed options that were previously missing from the `omit()` list, such as `ignore` and `reportUnusedDisableDirectives`. * The custom lint `merge()` function has been replaced with ESLint's own merging function, which correctly handles several cases that were broken before. * All non-loader related configuration has now been moved under the `baseConfig` key, since the options under it more closely relate to the options that users will have previously seen in `.eslintrc` files, thereby reducing user-confusion and making it possible to copy and paste the contents of the `baseConfig` section to a static `.eslintrc.*`. * Support has been added for projects that want to use their own non-generated `.eslintrc.*` file. They now only need to set `useEslintrc` to `true`, which will make the linting presets only set the loader-related options, preventing conflicts with the options set in their static `.eslintrc.*` file. * The `@neutrinojs/loader-merge` middleware has been removed, since its functionality was not sufficient for merging lint configuration correctly, and was not used for any other purpose. Fixes #1181. Fixes #382.
The refactor in #1182 inadvertently used babel-merge's `merge()` to merge ESLint configuration in this preset rather than deepmerge, since the existing `merge` import was not the same as in other presets from which the lint rule merging block was copied. In a later PR I think we should stop exporting a merge function from `@neutrinojs/compile-loader` named `merge`, to avoid the reduce the chance of this kind of naming conflict. Fixes: taskcluster/taskcluster-web-server#59 (comment)
In #1182, the previous broken ESLint config merging functionality was replaced by using an internal ESLint `merge` function from `config-ops`. Unfortunately in ESLint 6 that function no longer exists in a form that is easy for us to use, so in order to support ESLint 6, I have replaced it with simpler manual merges. These are virtually identical, with one difference - `rules` are now merged by a later rule entry completely replacing the first, rather than updating it. For example, merging these: `'foo': ['error', {'someSetting': false}]` `'foo': 'warn'` ...used to give: `'foo': ['warn', {'someSetting': false}]` ...but now results in: `'foo': 'warn'` I think this difference is a reasonable compromise for not having to rely on ESLint internals and/or implement our own more complex merging. I also believe hitting this will be rare, since: * it doesn't affect merging with rules defined inside an `extends` external file * it won't make a difference for rules that were already at default settings (or that were overridden with custom settings in the later rule definition being merged in) This more simplistic merging behaviour is also what's used by Neutrino 8 (#1182 landed for Neutrino 9 only) - and we still have the other bug fixes included in #1182 that were the primary motivation for refactoring in the first place. Refs #1423.
@neutrinojs/eslint, so that it now throws when passed options that are not supported by eslint-loader.baseConfigrather than silently ignoring some of them.settings,extends,rootoroverridesoptions).omit()list, such asignoreandreportUnusedDisableDirectives.merge()function has been replaced with ESLint's own merging function, which correctly handles several cases that were broken before.baseConfigkey, since the options under it more closely relate to the options that users will have previously seen in.eslintrcfiles, thereby reducing user-confusion and making it possible to copy and paste the contents of thebaseConfigsection to a static.eslintrc.*..eslintrc.*file. They now only need to setuseEslintrctotrue, which will make the linting presets only set the loader-related options, preventing conflicts with the options set in their static.eslintrc.*file.@neutrinojs/loader-mergemiddleware has been removed, since its functionality was not sufficient for merging lint configuration correctly, and was not used for any other purpose.Fixes #1181.
Fixes #382.