fix: support __proto__ in /* exported */ comments (#21261)

* fix: support `__proto__` in `/* exported */` comments

* bump @eslint/plugin-kit

Author: sethamus

lib/languages/js/source-code/source-code.js

@@ -981,7 +981,7 @@ class SourceCode extends TokenStore {
 	applyInlineConfig() {
 		const problems = [];
 		const configs = [];
-		const exportedVariables = {};
+		const exportedVariables = Object.create(null);
 		const inlineGlobals = Object.create(null);
 
 		this.getInlineConfigNodes().forEach(comment => {

package.json

@@ -137,7 +137,7 @@
     "@eslint/config-array": "^0.23.5",
     "@eslint/config-helpers": "^0.7.0",
     "@eslint/core": "^1.2.1",
-    "@eslint/plugin-kit": "^0.7.2",
+    "@eslint/plugin-kit": "^0.7.3",
     "@humanfs/node": "^0.16.6",
     "@humanwhocodes/module-importer": "^1.0.1",
     "@humanwhocodes/retry": "^0.4.2",

tests/lib/languages/js/source-code/source-code.js

@@ -2442,6 +2442,16 @@ describe("SourceCode", () => {
 					assert.notOk(variable.eslintExported);
 				});
 			});
+
+			it("should mark exported variable named __proto__", () => {
+				const code = "/*exported __proto__ */ var __proto__;";
+				const globalScope = loadGlobalScope(code);
+				const variable = globalScope.get("__proto__");
+
+				assert.isDefined(variable);
+				assert.isTrue(variable.eslintUsed);
+				assert.isTrue(variable.eslintExported);
+			});
 		});
 
 		it("should extract rule configuration", () => {

tests/lib/linter/linter.js

@@ -3160,6 +3160,19 @@ describe("Linter with FlatConfigArray", () => {
 							{ name: "__defineSetter__", writeable: true },
 						);
 					});
+
+					it("should define a global named __proto__", () => {
+						assertGlobalVariable(
+							"/*global __proto__ */",
+							{},
+							{ name: "__proto__", writeable: false },
+						);
+						assertGlobalVariable(
+							"/*global __proto__:writeable */",
+							{},
+							{ name: "__proto__", writeable: true },
+						);
+					});
 				});
 
 				describe("when evaluating code containing a /*global */ block with sloppy whitespace", () => {
@@ -3808,6 +3821,47 @@ describe("Linter with FlatConfigArray", () => {
 					linter.verify(code, config);
 					assert(spy && spy.calledOnce);
 				});
+
+				it("variable named __proto__ should be exported", () => {
+					const code = "/* exported __proto__ */\nvar __proto__;";
+					let spy;
+					const config = {
+						plugins: {
+							test: {
+								rules: {
+									checker: {
+										create(context) {
+											spy = sinon.spy(node => {
+												const scope =
+														context.sourceCode.getScope(
+															node,
+														),
+													proto = getVariable(
+														scope,
+														"__proto__",
+													);
+
+												assert.isTrue(proto.eslintUsed);
+												assert.isTrue(
+													proto.eslintExported,
+												);
+											});
+
+											return { Program: spy };
+										},
+									},
+								},
+							},
+						},
+						languageOptions: {
+							sourceType: "script",
+						},
+						rules: { "test/checker": "error" },
+					};
+
+					linter.verify(code, config);
+					assert(spy.calledOnce);
+				});
 			});
 
 			describe("/*eslint*/ Comments", () => {

tests/lib/rules/no-implicit-globals.js

@@ -506,6 +506,8 @@ ruleTester.run("no-implicit-globals", rule, {
 			languageOptions: { ecmaVersion: 2015 },
 		},
 		"/* exported foo, bar */ var foo = 1, bar = 2;",
+		"/* exported __proto__ */ var __proto__ = 1;",
+		"/* exported foo, __proto__, bar */ var foo = 1, __proto__ = 2, bar = 3;",
 
 		// `const`, `let` and `class`
 		{

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

@@ -306,6 +306,7 @@ ruleTester.run("no-unused-vars", rule, {
 		// exported variables should work
 		"/*exported toaster*/ var toaster = 'great'",
 		"/*exported toaster, poster*/ var toaster = 1; poster = 0;",
+		"/*exported __proto__*/ var __proto__ = 1;",
 		{
 			code: "/*exported x*/ var { x } = y",
 			languageOptions: { ecmaVersion: 6 },