feat: Support custom severity when reporting unused disable directives

Author: bmish

conf/default-cli-options.js

@@ -28,5 +28,6 @@ module.exports = {
     fix: false,
     allowInlineConfig: true,
     reportUnusedDisableDirectives: void 0,
+    reportUnusedDisableDirectivesSeverity: void 0,
     globInputPaths: true
 };

docs/src/use/command-line-interface.md

@@ -98,6 +98,7 @@ Output:
 Inline configuration comments:
   --no-inline-config              Prevent comments from changing config or rules
   --report-unused-disable-directives  Adds reported errors for unused eslint-disable directives
+  --report-unused-disable-directives-severity String  Choose what severity level that eslint-disable directives should be reported as
 
 Caching:
   --cache                         Only check changed files - default: false
@@ -572,7 +573,7 @@ npx eslint --no-inline-config file.js
 
 #### `--report-unused-disable-directives`
 
-This option causes ESLint to report directive comments like `// eslint-disable-line` when no errors would have been reported on that line anyway.
+This option causes ESLint to report disable directive comments like `// eslint-disable-line` as errors when there are no violations present.
 
 * **Argument Type**: No argument.
 
@@ -581,7 +582,7 @@ This can be useful to prevent future errors from unexpectedly being suppressed,
 ::: warning
 When using this option, it is possible that new errors start being reported whenever ESLint or custom rules are upgraded.
 
-For example, suppose a rule has a bug that causes it to report a false positive, and an `eslint-disable` comment is added to suppress the incorrect report. If the bug is then fixed in a patch release of ESLint, the `eslint-disable` comment becomes unused since ESLint is no longer generating an incorrect report. This results in a new reported error for the unused directive if the `report-unused-disable-directives` option is used.
+For example, suppose a rule has a bug that causes it to report a false positive, and an `eslint-disable` comment is added to suppress the incorrect report. If the bug is then fixed in a patch release of ESLint, the `eslint-disable` comment becomes unused since ESLint is no longer generating an incorrect report. This results in a new reported error for the unused directive if the `--report-unused-disable-directives` option is used.
 :::
 
 ##### `--report-unused-disable-directives` example
@@ -590,6 +591,16 @@ For example, suppose a rule has a bug that causes it to report a false positive,
 npx eslint --report-unused-disable-directives file.js
 ```
 
+#### `--report-unused-disable-directives-severity`
+
+Same as [`--report-unused-disable-directives`](#--report-unused-disable-directives), but allows you to specify the severity level (`error`, `warn`, `off`) of the reported errors. Only one of these two options can be used at a time.
+
+##### `--report-unused-disable-directives-severity` example
+
+```shell
+npx eslint --report-unused-disable-directives-severity warn file.js
+```
+
 ### Caching
 
 #### `--cache`

docs/src/use/configure/configuration-files-new.md

@@ -45,7 +45,7 @@ Each configuration object contains all of the information ESLint needs to execut
     * `parserOptions` - An object specifying additional options that are passed directly to the `parse()` or `parseForESLint()` method on the parser. The available options are parser-dependent.
 * `linterOptions` - An object containing settings related to the linting process.
     * `noInlineConfig` - A Boolean value indicating if inline configuration is allowed.
-    * `reportUnusedDisableDirectives` - A Boolean value indicating if unused disable directives should be tracked and reported.
+    * `reportUnusedDisableDirectives` - A severity string indicating if and how unused disable directives should be tracked and reported. For legacy compatibility, `true` is equivalent to `"warn"` and `false` is equivalent to `"off"`. (default: `"off"`)
 * `processor` - Either an object containing `preprocess()` and `postprocess()` methods or a string indicating the name of a processor inside of a plugin (i.e., `"pluginName/processorName"`).
 * `plugins` - An object containing a name-value mapping of plugin names to plugin objects. When `files` is specified, these plugins are only available to the matching files.
 * `rules` - An object containing the configured rules. When `files` or `ignores` are specified, these rule configurations are only available to the matching files.
@@ -208,20 +208,22 @@ export default [
 
 #### Reporting unused disable directives
 
-Disable directives such as `/*eslint-disable*/` and `/*eslint-disable-next-line*/` are used to disable ESLint rules around certain portions of code. As code changes, it's possible for these directives to no longer be needed because the code has changed in such a way that the rule is no longer triggered. You can enable reporting of these unused disable directives by setting the `reportUnusedDisableDirectives` option to `true`, as in this example:
+Disable directives such as `/*eslint-disable*/` and `/*eslint-disable-next-line*/` are used to disable ESLint rules around certain portions of code. As code changes, it's possible for these directives to no longer be needed because the code has changed in such a way that the rule is no longer triggered. You can enable reporting of these unused disable directives by setting the `reportUnusedDisableDirectives` option to a severity string, as in this example:
 
 ```js
 export default [
     {
         files: ["**/*.js"],
         linterOptions: {
-            reportUnusedDisableDirectives: true
+            reportUnusedDisableDirectives: "error"
         }
     }
 ];
 ```
 
-By default, unused disable directives are reported as warnings. You can change this setting using the `--report-unused-disable-directives` command line option.
+You can override this setting using the [`--report-unused-disable-directives`](../command-line-interface#--report-unused-disable-directives) or the [`--report-unused-disable-directives-severity`](../command-line-interface#--report-unused-disable-directives-severity) command line options.
+
+For legacy compatibility, `true` is equivalent to `"warn"` and `false` is equivalent to `"off"`.
 
 ### Configuring language options
 

docs/src/use/configure/rules.md

@@ -302,8 +302,8 @@ To report unused `eslint-disable` comments, use the `reportUnusedDisableDirectiv
 ```json
 {
   "rules": {...},
-  "reportUnusedDisableDirectives": true
+  "reportUnusedDisableDirectives": "error"
 }
 ```
 
-This setting is similar to [--report-unused-disable-directives](../command-line-interface#--report-unused-disable-directives) CLI option, but doesn't fail linting (reports as `"warn"` severity).
+This setting is similar to [--report-unused-disable-directives](../command-line-interface#--report-unused-disable-directives) and [--report-unused-disable-directives-severity](../command-line-interface#--report-unused-disable-directives-severity) CLI options.

lib/cli-engine/cli-engine.js

@@ -83,7 +83,7 @@ const validFixTypes = new Set(["directive", "problem", "suggestion", "layout"]);
  * @property {string[]} [plugins] An array of plugins to load.
  * @property {Record<string,RuleConf>} [rules] An object of rules to use.
  * @property {string[]} [rulePaths] An array of directories to load custom rules from.
- * @property {boolean} [reportUnusedDisableDirectives] `true` adds reports for unused eslint-disable directives
+ * @property {boolean|string} [reportUnusedDisableDirectives] `true` or `error` adds reports for unused eslint-disable directives
  * @property {boolean} [globInputPaths] Set to false to skip glob resolution of input file paths to lint (default: true). If false, each input file paths is assumed to be a non-glob path to an existing file.
  * @property {string} [resolvePluginsRelativeTo] The folder where plugins should be resolved from, defaulting to the CWD
  */
@@ -215,7 +215,7 @@ function calculateStatsPerRun(results) {
  * @param {ConfigArray} config.config The config.
  * @param {boolean} config.fix If `true` then it does fix.
  * @param {boolean} config.allowInlineConfig If `true` then it uses directive comments.
- * @param {boolean} config.reportUnusedDisableDirectives If `true` then it reports unused `eslint-disable` comments.
+ * @param {boolean|string} config.reportUnusedDisableDirectives If `true` or `error`, then it reports unused `eslint-disable` comments.
  * @param {FileEnumerator} config.fileEnumerator The file enumerator to check if a path is a target or not.
  * @param {Linter} config.linter The linter instance to verify.
  * @returns {LintResult} The result of linting.

lib/cli.js

@@ -89,6 +89,7 @@ async function translateOptions({
     plugin,
     quiet,
     reportUnusedDisableDirectives,
+    reportUnusedDisableDirectivesSeverity,
     resolvePluginsRelativeTo,
     rule,
     rulesdir
@@ -177,7 +178,7 @@ async function translateOptions({
         ignore,
         overrideConfig,
         overrideConfigFile,
-        reportUnusedDisableDirectives: reportUnusedDisableDirectives ? "error" : void 0
+        reportUnusedDisableDirectives: reportUnusedDisableDirectivesSeverity || (reportUnusedDisableDirectives ? "error" : void 0)
     };
 
     if (configType === "flat") {
@@ -377,6 +378,11 @@ const cli = {
             return 2;
         }
 
+        if (options.reportUnusedDisableDirectives && options.reportUnusedDisableDirectivesSeverity) {
+            log.error("The --report-unused-disable-directives option and the --report-unused-disable-directives-severity option cannot be used together.");
+            return 2;
+        }
+
         const ActiveESLint = usingFlatConfig ? FlatESLint : ESLint;
 
         const engine = new ActiveESLint(await translateOptions(options, usingFlatConfig ? "flat" : "eslintrc"));

lib/config/flat-config-schema.js

@@ -222,6 +222,16 @@ const booleanSchema = {
     validate: "boolean"
 };
 
+/** @type {ObjectPropertySchema} */
+const booleanOrStringSchema = {
+    merge: "replace",
+    validate(value) {
+        if (typeof value !== "string" && typeof value !== "boolean") {
+            throw new TypeError("Expected a string or a boolean.");
+        }
+    }
+};
+
 /** @type {ObjectPropertySchema} */
 const deepObjectAssignSchema = {
     merge(first = {}, second = {}) {
@@ -447,7 +457,7 @@ exports.flatConfigSchema = {
     linterOptions: {
         schema: {
             noInlineConfig: booleanSchema,
-            reportUnusedDisableDirectives: booleanSchema
+            reportUnusedDisableDirectives: booleanOrStringSchema
         }
     },
     languageOptions: {

lib/eslint/eslint-helpers.js

@@ -675,7 +675,7 @@ function processOptions({
     overrideConfig = null,
     overrideConfigFile = null,
     plugins = {},
-    reportUnusedDisableDirectives = null, // ← should be null by default because if it's a string then it overrides the 'reportUnusedDisableDirectives' setting in config files. And we cannot use `overrideConfig.reportUnusedDisableDirectives` instead because we cannot configure the `error` severity with that.
+    reportUnusedDisableDirectives = null, // ← should be null by default because if it's a string then it overrides the 'reportUnusedDisableDirectives' setting in config files. And we cannot use `overrideConfig.reportUnusedDisableDirectives` instead because we cannot configure the `error` severity with that. TODO: should anything change based on this comment?
     ...unknownOptions
 }) {
     const errors = [];

lib/eslint/eslint.js

@@ -165,7 +165,7 @@ function processOptions({
     overrideConfig = null,
     overrideConfigFile = null,
     plugins = {},
-    reportUnusedDisableDirectives = null, // ← should be null by default because if it's a string then it overrides the 'reportUnusedDisableDirectives' setting in config files. And we cannot use `overrideConfig.reportUnusedDisableDirectives` instead because we cannot configure the `error` severity with that.
+    reportUnusedDisableDirectives = null, // ← should be null by default because if it's a string then it overrides the 'reportUnusedDisableDirectives' setting in config files. And we cannot use `overrideConfig.reportUnusedDisableDirectives` instead because we cannot configure the `error` severity with that. TODO: should anything change based on this comment?
     resolvePluginsRelativeTo = null, // ← should be null by default because if it's a string then it suppresses RFC47 feature.
     rulePaths = [],
     useEslintrc = true,

lib/eslint/flat-eslint.js

@@ -466,7 +466,7 @@ async function calculateConfigArray(eslint, {
  * @param {FlatConfigArray} config.configs The config.
  * @param {boolean} config.fix If `true` then it does fix.
  * @param {boolean} config.allowInlineConfig If `true` then it uses directive comments.
- * @param {boolean} config.reportUnusedDisableDirectives If `true` then it reports unused `eslint-disable` comments.
+ * @param {boolean|string} config.reportUnusedDisableDirectives If `true` or `error`, then it reports unused `eslint-disable` comments.
  * @param {Linter} config.linter The linter instance to verify.
  * @returns {LintResult} The result of linting.
  * @private