Introduce "warning" policy; change no-var to a warning

CHANGELOG.md

@@ -5,6 +5,32 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [16.0.1] - 2020-10-30
+
+- Introduce "warning" system for disruptive rules (read more below)
+- Change rule to a "warning": Require let or const instead of var ([no-var](https://eslint.org/docs/rules/no-var)) [#633](https://github.com/standard/standard/issues/633)
+
+`standard` treats all rule violations as errors, which means that `standard`
+will exit with a non-zero (error) exit code.
+
+However, we may occasionally release a new major version of `standard`
+which changes a rule that affects the majority of `standard` users (for example,
+transitioning from `var` to `let`/`const`). We do this only when we think the
+advantage is worth the cost and only when the rule is
+[auto-fixable](https://standardjs.com/#is-there-an-automatic-formatter).
+
+In these situations, we have a "transition period" where the rule change is only
+a "warning". Warnings don't cause `standard` to return a non-zero (error)
+exit code. However, a warning message will still print to the console. During
+the transition period, `using standard --fix` will update your code so that it's
+ready for the next major version.
+
+The slow and careful approach is what we strive for with `standard`. We're
+generally extremely conservative in enforcing the usage of new language
+features. We want using `standard` to be light and fun and so we're careful
+about making changes that may get in your way. As always, you can
+[disable a rule](https://standardjs.com/#how-do-i-disable-a-rule) at any time, if necessary.
+
 ## [16.0.0] - 2020-10-28
 
 We're super excited to announce `standard` 16!
@@ -26,10 +52,10 @@ code to match the newly added rules.
 
 - 🌟 Support the `.gitignore` ignore syntax from the command line [#1117](https://github.com/standard/standard/issues/1117)
   - In older versions, the command `standard src` would not lint the `src/` folder
-  - Instead, a glob pattern needed like `standard src/**/*.js` was required
+  - Instead, a glob pattern like `standard src/**/*.js` was required
   - This is now fixed! You can run `standard src` to lint the `src/` folder!
 
-- 🌟 Support relative paths from the command line (e.g. `standard ../src/*.js`) [#1384](https://github.com/standard/standard/issues/1384)
+- 🌟 Support relative paths from the command line in more situations (e.g. `standard ../src/*.js`) [#1384](https://github.com/standard/standard/issues/1384)
 
 - 🌟 New `extensions` option for linting additional extensions besides `.js`, `.jsx`, `.mjs`, and `.cjs`
   - Can be configured with the `--ext` command line flag or in `package.json`:
@@ -47,13 +73,14 @@ code to match the newly added rules.
     }
     ```
 
+- 🌟 New cache directory location, respecting `XDG_CACHE_HOME` preference, with fallback to `~/.cache/standard` [standard-engine/#214](https://github.com/standard/standard-engine/pull/214)
+
 ### Changed features
 
 - Update `eslint` from `~7.11.0` to `~7.12.1`
 
 - Update `standard-engine` from `^12` to `^14`
-  - Fix inaccurate `--help` command which indicates that `bundle.js` is automatically ignored when it is not [standard-engine/#224](https://github.com/standard/standard-engine/pull/224)
-  - New cache directory location, respecting `XDG_CACHE_HOME` preference, with fallback to `~/.cache/standard` [standard-engine/#214](https://github.com/standard/standard-engine/pull/214)
+  - Fix inaccurate `--help` command which indicates that `bundle.js` is automatically ignored when it is not anymore [standard-engine/#224](https://github.com/standard/standard-engine/pull/224)
   - Remove `deglob` package and use built-in ESLint folder-traversal support
 
 - Paths with square brackets (e.g. `[` and `]`) are no longer skipped [#1333](https://github.com/standard/standard/issues/1333)
@@ -1016,7 +1043,9 @@ In `package.json`, use the "standard" property:
 
 [view diff](https://github.com/standard/standard/compare/v3.9.0...v4.0.0)
 
-[unreleased]: https://github.com/standard/standard/compare/v16.0.0...HEAD
+[unreleased]: https://github.com/standard/standard/compare/v16.0.1...HEAD
+
+[16.0.1]: https://github.com/standard/standard/compare/v16.0.0...v16.0.1
 
 [16.0.0]: https://github.com/standard/standard/compare/v15.0.1...v16.0.0
 

README.md

@@ -59,18 +59,18 @@ Give it a try by running `npx standard --fix` right now!
   - [But this isn't a real web standard!](#but-this-isnt-a-real-web-standard)
   - [Is there an automatic formatter?](#is-there-an-automatic-formatter)
   - [How do I ignore files?](#how-do-i-ignore-files)
-  - [How do I hide a certain warning?](#how-do-i-hide-a-certain-warning)
+  - [How do I disable a rule?](#how-do-i-disable-a-rule)
   - [I use a library that pollutes the global namespace. How do I prevent "variable is not defined" errors?](#i-use-a-library-that-pollutes-the-global-namespace-how-do-i-prevent-variable-is-not-defined-errors)
   - [How do I use experimental JavaScript (ES Next) features?](#how-do-i-use-experimental-javascript-es-next-features)
   - [Can I use a JavaScript language variant, like Flow or TypeScript?](#can-i-use-a-javascript-language-variant-like-flow-or-typescript)
   - [What about Mocha, Jest, Jasmine, QUnit, etc?](#what-about-mocha-jest-jasmine-qunit-etc)
   - [What about Web Workers and Service Workers?](#what-about-web-workers-and-service-workers)
+  - [What is the difference between warnings and errors?](#what-is-the-difference-between-warnings-and-errors)
   - [Can I check code inside of Markdown or HTML files?](#can-i-check-code-inside-of-markdown-or-html-files)
   - [Is there a Git `pre-commit` hook?](#is-there-a-git-pre-commit-hook)
   - [How do I make the output all colorful and pretty?](#how-do-i-make-the-output-all-colorful-and-pretty)
   - [Is there a Node.js API?](#is-there-a-nodejs-api)
   - [How do I contribute to StandardJS?](#how-do-i-contribute-to-standardjs)
-- [License](#license)
 
 ## Install
 
@@ -399,13 +399,13 @@ that, add a `standard.ignore` property to `package.json`:
 }
 ```
 
-## How do I hide a certain warning?
+## How do I disable a rule?
 
-In rare cases, you'll need to break a rule and hide the warning generated by
+In rare cases, you'll need to break a rule and hide the error generated by
 `standard`.
 
 JavaScript Standard Style uses [ESLint](http://eslint.org/) under-the-hood and
-you can hide warnings as you normally would if you used ESLint directly.
+you can hide errors as you normally would if you used ESLint directly.
 
 To get verbose output (so you can find the particular rule name to ignore), run:
 
@@ -633,6 +633,29 @@ For Service workers, add this instead:
 /* eslint-env serviceworker */
 ```
 
+## What is the difference between warnings and errors?
+
+`standard` treats all rule violations as errors, which means that `standard`
+will exit with a non-zero (error) exit code.
+
+However, we may occasionally release a new major version of `standard`
+which changes a rule that affects the majority of `standard` users (for example,
+transitioning from `var` to `let`/`const`). We do this only when we think the
+advantage is worth the cost and only when the rule is
+[auto-fixable](#is-there-an-automatic-formatter).
+
+In these situations, we have a "transition period" where the rule change is only
+a "warning". Warnings don't cause `standard` to return a non-zero (error)
+exit code. However, a warning message will still print to the console. During
+the transition period, `using standard --fix` will update your code so that it's
+ready for the next major version.
+
+The slow and careful approach is what we strive for with `standard`. We're
+generally extremely conservative in enforcing the usage of new language
+features. We want using `standard` to be light and fun and so we're careful
+about making changes that may get in your way. As always, you can
+[disable a rule](#how-do-i-disable-a-rule) at any time, if necessary.
+
 ## Can I check code inside of Markdown or HTML files?
 
 To check code inside Markdown files, use [`standard-markdown`](https://www.npmjs.com/package/standard-markdown).

package.json

@@ -15,7 +15,7 @@
   },
   "dependencies": {
     "eslint": "~7.12.1",
-    "eslint-config-standard": "16.0.0",
+    "eslint-config-standard": "16.0.1",
     "eslint-config-standard-jsx": "10.0.0",
     "eslint-plugin-import": "~2.22.1",
     "eslint-plugin-node": "~11.1.0",