OptionsValidator plugin extension and linter service.

pkg/analysis_server/lib/src/services/linter/linter.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library services.src.linter;
+
+import 'package:analyzer/plugin/options.dart';
+import 'package:analyzer/analyzer.dart';
+import 'package:yaml/yaml.dart';
+import 'package:linter/src/rules.dart';
+import 'package:linter/src/linter.dart';
+
+/**
+ * An error code indicating an undefined lint rule.
+ *
+ * Parameters:
+ * 0: the rule name
+ */
+const AnalysisOptionsWarningCode UNDEFINED_LINT_WARNING =
+    const AnalysisOptionsWarningCode(
+        'UNDEFINED_LINT_WARNING', "Undefined lint rule '{0}'");
+
+/// Validates `linter` rule configurations.
+class LinterRuleOptionsValidator extends OptionsValidator {
+  static const linter = 'linter';
+  static const rulesKey = 'rules';
+  @override
+  List<AnalysisError> validate(
+      ErrorReporter reporter, Map<String, YamlNode> options) {
+    List<AnalysisError> errors = <AnalysisError>[];
+    var node = options[linter];
+    if (node is YamlMap) {
+      var rules = node.nodes[rulesKey];
+      validateRules(rules, reporter);
+    }
+    return errors;
+  }
+
+  validateRules(dynamic rules, ErrorReporter reporter) {
+    if (rules is YamlList) {
+      //TODO(pq): migrate this to a proper API once there is one.
+      Iterable<String> registeredLints = ruleRegistry.map((r) => r.name);
+      rules.nodes.forEach((YamlNode ruleNode) {
+        if (!registeredLints.contains(ruleNode.value)) {
+          reporter.reportErrorForSpan(
+              UNDEFINED_LINT_WARNING, ruleNode.span, [ruleNode.value]);
+        }
+      });
+    }
+  }
+}