Fix: parsing regex option failing when defined in a comment.

(fixes eslint#9366) levn parsing string differently than JSON.parse,
e.g.
JSON.parse(          '{ "foo": "\\n" }') // => { foo: '\n' }
levn.parse('Object', '{ "foo": "\\n" }') // => { foo: '\\n' }

lib/linter.js

@@ -94,6 +94,10 @@ function parseJsonConfig(string, location) {
 
     // Parses a JSON-like comment by the same way as parsing CLI option.
     try {
+
+        // https://github.com/eslint/eslint/issues/9366
+        string = string.replace(/\\\\/g, "\\");
+
         items = levn.parse("Object", string) || {};
 
         // Some tests say that it should ignore invalid comments such as `/*eslint no-alert:abc*/`.

tests/lib/linter.js

@@ -1513,6 +1513,15 @@ describe("Linter", () => {
             assert.include(messages[0].nodeType, "CallExpression");
         });
 
+        // https://github.com/eslint/eslint/issues/9366
+        it("rules should parse regex option correctly", () => {
+            const config = {};
+            const code = String.raw`/* eslint id-match: [2, "^(([^$\\W]|\\$[a-f\\d]{2})+|[$_]\\w*|[^\\W\\d]\\w*|[A-Z]([A-Z_]*[A-Z])?)$", {properties: true}] */ var is$2dvoid = 0;`;
+            const messages = linter.verify(code, config, filename, false);
+
+            assert.equal(messages.length, 0);
+        });
+
         it("rules should not change initial config", () => {
             const config = { rules: { strict: 2 } };
             const codeA = "/*eslint strict: 0*/ function bar() { return 2; }";