Breaking: validate parserOptions (fixes eslint#9687)

lib/config/config-validator.js

@@ -261,13 +261,33 @@ function validate(config, source, ruleMapper, envContext) {
     validateConfigSchema(config, source);
     validateRules(config.rules, source, ruleMapper);
     validateEnvironment(config.env, source, envContext);
+    validateParserOptions(config.parserOptions, source);
 
     for (const override of config.overrides || []) {
         validateRules(override.rules, source, ruleMapper);
         validateEnvironment(override.env, source, envContext);
     }
 }
 
+/**
+ * validate parserOptions
+ * @param {Object} parserOptions the parserOptions to validate.
+ * @param {string} source The name of the configuration source to report in any errors.
+ * @returns {void}
+ */
+function validateParserOptions(parserOptions = {}, source) {
+    if (parserOptions.ecmaVersion) {
+        if (typeof parserOptions.ecmaVersion !== "number") {
+            throw new Error(`parserOptions.ecmaVersion must be a number (file:${source})!`);
+
+        }
+
+        if (parserOptions.ecmaVersion < 6 && parserOptions.sourceType === "module") {
+            throw new Error("sourceType 'module' is not supported in ecmaVersion < 6 (file:#{source})!");
+        }
+    }
+}
+
 //------------------------------------------------------------------------------
 // Public Interface
 //------------------------------------------------------------------------------