New: no-unused-enable rule

Author: mysticatea

docs/rules/no-unused-enable.md

@@ -0,0 +1,38 @@
+# disallows unused `eslint-enable` comments (eslint-comments/no-unused-enable)
+
+This rule warns `eslint-enable` directive-comments which have no effect.
+
+## Rule Details
+
+Examples of :-1: **incorrect** code for this rule:
+
+```js
+/*eslint eslint-comments/no-unused-enable: error */
+
+/*eslint-disable no-undef */
+doSomething()
+/*eslint-enable no-undef-init */ "※ 'no-undef-init' rule is re-enabled but it has not been disabled."
+```
+
+```js
+/*eslint eslint-comments/no-unused-enable: error */
+
+doSomething()
+/*eslint-enable */ "※ ESLint rules are re-enabled but those have not been disabled."
+```
+
+Examples of :+1: **correct** code for this rule:
+
+```js
+/*eslint eslint-comments/no-unused-enable: error */
+
+/*eslint-disable no-undef */
+doSomething()
+/*eslint-enable no-undef */
+```
+
+```js
+/*eslint eslint-comments/no-unused-enable: error */
+
+doSomething()
+```

lib/rules/no-unused-enable.js

@@ -0,0 +1,48 @@
+/**
+ * @author Toru Nagashima
+ * @copyright 2016 Toru Nagashima. All rights reserved.
+ * See LICENSE file in root directory for full license.
+ */
+"use strict"
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const DisabledArea = require("../disabled-area")
+const utils = require("../utils")
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        docs: {
+            description: "disallows unused `eslint-enable` comments",
+            category: "Best Practices",
+            recommended: false,
+        },
+        fixable: false,
+        schema: [],
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode()
+        const disabledArea = DisabledArea.get(sourceCode)
+
+        return {
+            Program() {
+                for (const item of disabledArea.unusedEnableDirectives) {
+                    context.report({
+                        loc: utils.toRuleIdLocation(item.comment, item.ruleId),
+                        message: (item.ruleId) ?
+                            "'{{ruleId}}' rule is re-enabled but it has not been disabled." :
+                            "ESLint rules are re-enabled but those have not been disabled.",
+                        data: item,
+                    })
+                }
+            },
+        }
+    },
+}

tests/lib/rules/no-unused-enable.js

@@ -0,0 +1,95 @@
+/**
+ * @author Toru Nagashima
+ * @copyright 2016 Toru Nagashima. All rights reserved.
+ * See LICENSE file in root directory for full license.
+ */
+"use strict"
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const RuleTester = require("eslint").RuleTester
+const rule = require("../../../lib/rules/no-unused-enable")
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+const tester = new RuleTester()
+
+tester.run("no-unused-enable", rule, {
+    valid: [
+        `
+/*eslint no-undef:error*/
+/*eslint-disable*/
+var a = b
+/*eslint-enable*/
+`,
+        `
+/*eslint no-undef:error*/
+/*eslint-disable no-undef*/
+var a = b
+/*eslint-enable no-undef*/
+`,
+        `
+/*eslint no-undef:error*/
+/*eslint-disable no-undef*/
+var a = b
+/*eslint-enable*/
+`,
+        `
+/*eslint no-undef:error, no-unused-vars:error*/
+/*eslint-disable no-undef,no-unused-vars*/
+var a = b
+/*eslint-enable no-undef*/
+`,
+        `
+/*eslint no-undef:error, no-unused-vars:error*/
+/*eslint-disable no-undef,no-unused-vars*/
+var a = b
+/*eslint-enable*/
+`,
+    ],
+    invalid: [
+        {
+            code: "/*eslint-enable*/",
+            errors: [
+                {
+                    message: "ESLint rules are re-enabled but those have not been disabled.",
+                    line: 1,
+                    column: 0,
+                    endLine: 1,
+                    endColumn: 18,
+                },
+            ],
+        },
+        {
+            code: "/*eslint-enable no-undef*/",
+            errors: [
+                {
+                    message: "'no-undef' rule is re-enabled but it has not been disabled.",
+                    line: 1,
+                    column: 17,
+                    endLine: 1,
+                    endColumn: 25,
+                },
+            ],
+        },
+        {
+            code: `
+/*eslint-disable no-unused-vars*/
+/*eslint-enable no-undef*/
+`,
+            errors: [
+                {
+                    message: "'no-undef' rule is re-enabled but it has not been disabled.",
+                    line: 3,
+                    column: 17,
+                    endLine: 3,
+                    endColumn: 25,
+                },
+            ],
+        },
+    ],
+})