From feeebeeb67d7e575d2354ed41673bd98de99cde5 Mon Sep 17 00:00:00 2001
From: David Gasperoni <mcdado@gmail.com>
Date: Mon, 13 Jan 2020 17:39:44 +0100
Subject: [PATCH] Update: Add option "ignoreGlobals" to camelcase rule (fixes
 11716)

---
 docs/rules/camelcase.md      | 24 ++++++++++++++++++++++
 lib/rules/camelcase.js       | 40 ++++++++++++++++++++++++++++++++++++
 tests/lib/rules/camelcase.js | 22 ++++++++++++++++++++
 3 files changed, 86 insertions(+)

diff --git a/docs/rules/camelcase.md b/docs/rules/camelcase.md
index 96135f8c9326..0a9c326445cf 100644
--- a/docs/rules/camelcase.md
+++ b/docs/rules/camelcase.md
@@ -16,6 +16,8 @@ This rule has an object option:
 * `"ignoreDestructuring": true` does not check destructured identifiers (but still checks any use of those identifiers later in the code)
 * `"ignoreImports": false` (default) enforces camelcase style for ES2015 imports
 * `"ignoreImports": true` does not check ES2015 imports (but still checks any use of the imports later in the code except function arguments)
+* `"ignoreGlobals": false` (default) enforces camelcase style for global variables
+* `"ignoreGlobals": true` does not enforce camelcase style for global variables
 * `allow` (`string[]`) list of properties to accept. Accept regex.
 
 ### properties: "always"
@@ -217,6 +219,28 @@ Examples of **correct** code for this rule with the `{ "ignoreImports": true }`
 import { snake_cased } from 'mod';
 ```
 
+### ignoreGlobals: false
+
+Examples of **incorrect** code for this rule with the default `{ "ignoreGlobals": false }` option:
+
+```js
+/*eslint camelcase: ["error", {ignoreGlobals: false}]*/
+/* global some_property */
+
+const property = some_property;
+```
+
+### ignoreGlobals: true
+
+Examples of **correct** code for this rule with the `{ "ignoreGlobals": true }` option:
+
+```js
+/*eslint camelcase: ["error", {ignoreGlobals: true}]*/
+/* global some_property */
+
+const property = some_property;
+```
+
 ## allow
 
 Examples of **correct** code for this rule with the `allow` option:
diff --git a/lib/rules/camelcase.js b/lib/rules/camelcase.js
index a06c7f94042a..8ef4bc6fbf8b 100644
--- a/lib/rules/camelcase.js
+++ b/lib/rules/camelcase.js
@@ -5,6 +5,28 @@
 
 "use strict";
 
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const { findVariable } = require("eslint-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Determines whether the given identifier node is a reference to a global variable.
+ * @param {ASTNode} node `Identifier` node to check.
+ * @param {Scope} scope Scope to which the node belongs.
+ * @returns {boolean} True if the identifier is a reference to a global variable.
+ */
+function isGlobalReference(node, scope) {
+    const variable = findVariable(scope, node);
+
+    return variable !== null && variable.scope.type === "global" && variable.defs.length === 0;
+}
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -32,6 +54,10 @@ module.exports = {
                         type: "boolean",
                         default: false
                     },
+                    ignoreGlobals: {
+                        type: "boolean",
+                        default: false
+                    },
                     properties: {
                         enum: ["always", "never"]
                     },
@@ -61,7 +87,9 @@ module.exports = {
         let properties = options.properties || "";
         const ignoreDestructuring = options.ignoreDestructuring;
         const ignoreImports = options.ignoreImports;
+        const ignoreGlobals = options.ignoreGlobals;
         const allow = options.allow || [];
+        const currentScope = context.getScope();
 
         if (properties !== "always" && properties !== "never") {
             properties = "always";
@@ -229,6 +257,18 @@ module.exports = {
                         report(node);
                     }
 
+                // Check if it's a global variable
+                } else if (isGlobalReference(node, currentScope)) {
+
+                    if (ignoreGlobals) {
+                        return;
+                    }
+
+                    // Report only if the local imported identifier is underscored
+                    if (nameIsUnderscored) {
+                        report(node);
+                    }
+
                 // Report anything that is underscored that isn't a CallExpression
                 } else if (nameIsUnderscored && !ALLOWED_PARENT_TYPES.has(effectiveParent.type)) {
                     report(node);
diff --git a/tests/lib/rules/camelcase.js b/tests/lib/rules/camelcase.js
index 1181561efa8f..fdd15ee6a242 100644
--- a/tests/lib/rules/camelcase.js
+++ b/tests/lib/rules/camelcase.js
@@ -161,6 +161,16 @@ ruleTester.run("camelcase", rule, {
             options: [{ ignoreImports: false }],
             parserOptions: { ecmaVersion: 6, sourceType: "module" }
         },
+        {
+            code: "var _camelCased = camelCased",
+            options: [{ ignoreGlobals: false }],
+            globals: { camelCased: false }
+        },
+        {
+            code: "var camelCased = snake_cased",
+            options: [{ ignoreGlobals: true }],
+            globals: { snake_cased: false } // eslint-disable-line camelcase
+        },
         {
             code: "function foo({ no_camelcased: camelCased }) {};",
             parserOptions: { ecmaVersion: 6 }
@@ -590,6 +600,18 @@ ruleTester.run("camelcase", rule, {
                 }
             ]
         },
+        {
+            code: "var camelCased = snake_cased",
+            options: [{ ignoreGlobals: false }],
+            globals: { snake_cased: false }, // eslint-disable-line camelcase
+            errors: [
+                {
+                    messageId: "notCamelCase",
+                    data: { name: "snake_cased" },
+                    type: "Identifier"
+                }
+            ]
+        },
         {
             code: "function foo({ no_camelcased }) {};",
             parserOptions: { ecmaVersion: 6 },