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

afbea78 accidentally introduced a regression where parsers would get passed additional "default" options even when the user did not specify them. This updates the default parserOptions to prevent any unexpected options from getting passed to parsers.

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/eslint.js

@@ -3860,6 +3860,13 @@ 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);
+            });
         });
     }