Fix: don't pass default parserOptions to custom parsers (fixes #8744)

conf/default-config-options.js

@@ -25,9 +25,5 @@ module.exports = deepFreeze({
     rules: {},
     settings: {},
     parser: "espree",
-    parserOptions: {
-        ecmaVersion: 5,
-        sourceType: "script",
-        ecmaFeatures: {}
-    }
+    parserOptions: {}
 });

lib/linter.js

@@ -455,8 +455,8 @@ function normalizeEcmaVersion(ecmaVersion, isModule) {
  */
 function prepareConfig(config, envContext) {
     config.globals = config.globals || {};
-    const copiedRules = Object.assign({}, defaultConfig.rules);
-    let parserOptions = Object.assign({}, defaultConfig.parserOptions);
+    const copiedRules = {};
+    let parserOptions = {};
 
     if (typeof config.rules === "object") {
         Object.keys(config.rules).forEach(k => {

tests/fixtures/parsers/throws-with-options.js

@@ -0,0 +1,10 @@
+"use strict";
+
+const espree = require("espree");
+
+exports.parse = (sourceText, options) => {
+    if (options.ecmaVersion) {
+        throw new Error("Expected no parserOptions to be used");
+    }
+    return espree.parse(sourceText, options);
+};

tests/lib/linter.js

@@ -3905,6 +3905,13 @@ describe("eslint", () => {
                 assert.equal(messages[0].message, errorPrefix + require(parser).expectedError);
             });
 
+            it("should not pass any default parserOptions to the parser", () => {
+                const parser = path.join(parserFixtures, "throws-with-options.js");
+
+                const messages = linter.verify(";", { parser }, "filename");
+
+                assert.strictEqual(messages.length, 0);
+            });
         });
     }