OptionsValidator plugin extension and linter service.

pkg/analyzer/lib/plugin/options.dart

 // Copyright (c) 2015, 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.
 
 /// Support for client code that wants to consume options contributed to the
 /// analysis options file.
 library analyzer.plugin.options;
 
+import 'package:analyzer/analyzer.dart';

[Brian Wilkerson, 2015/10/24 15:32:17]

Whatever we're importing from here is exported from somewhere else. I'd prefer
to import it from the original library rather than indirectly.

[pquitslund, 2015/10/26 15:48:59]

Interesting. Maybe we should cook up a lint for this?  Or maybe it doesn't come
up often enough?

[Brian Wilkerson, 2015/10/26 16:07:14]

I suspect that this doesn't come up very often. It's generally only a problem if
a type is made visible from two or more public libraries (and because of
history, that isn't the case here), which probably doesn't happen very often.
And even then, it isn't clear that it would matter which one it was imported
from. I think this is just a weird case.

 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/plugin/options_plugin.dart';
 import 'package:plugin/plugin.dart';
 import 'package:yaml/yaml.dart';
 
 /// The identifier of the extension point that allows plugins to access
 /// options defined in the analysis options file. The object used as an
 /// extension must be an [OptionsProcessor].
 final String OPTIONS_PROCESSOR_EXTENSION_POINT_ID = Plugin.join(
     OptionsPlugin.UNIQUE_IDENTIFIER,
     OptionsPlugin.OPTIONS_PROCESSOR_EXTENSION_POINT);
 
+/// The identifier of the extension point that allows plugins to validate
+/// options defined in the analysis options file. The object used as an
+/// extension must be an [OptionsValidator].
+final String OPTIONS_VALIDATOR_EXTENSION_POINT_ID = Plugin.join(
+    OptionsPlugin.UNIQUE_IDENTIFIER,
+    OptionsPlugin.OPTIONS_VALIDATOR_EXTENSION_POINT);
+
 /// Processes options defined in the analysis options file.
 ///
 /// The options file format is intentionally very open-ended, giving clients
 /// utmost flexibility in defining their own options.  The only hardfast
 /// expectation is that options files will contain a mapping from Strings
 /// (identifying 'scopes') to associated options.  For example, the given
 /// content
 ///
 ///     linter:
 ///       rules:
@@ skipping 23 matching lines @@
   /// The options file is processed on analyzer initialization and
   /// subsequently when the file is changed on disk.  In the event of a
   /// change notification, note that the notification simply indicates
   /// a change on disk. Content in specific option scopes may or may not
   /// be different. It is up to the implementer to check whether specific
   /// options have changed and to handle those changes appropriately. In
   /// addition to the [options] map, the associated analysis [context] is
   /// provided as well to allow for context-specific configuration.
   void optionsProcessed(AnalysisContext context, Map<String, YamlNode> options);
 }
+
+/// Validates options as defined in an analysis options file.
+///
+/// See [OptionsProcessor] for a description of the options file format.
+///

[Brian Wilkerson, 2015/10/24 15:32:17]

In the server plugins, I've been adding text indicating what clients can and
cannot do with the public classes. For an interface like this, the text is:

Clients may implement this class when implementing plugins.

[pquitslund, 2015/10/26 15:48:59]

Cool.  Added.  Do you have a doc anywhere with these guidelines?  If not, maybe
added to the CONTRIBUTING doc?

[Brian Wilkerson, 2015/10/26 16:07:14]

No. We've been discussing the possibility of adding annotations in place of, or
in addition to, these comments.
Maybe. Is it normally customized? It looks like boiler-plate to me.

+abstract class OptionsValidator {
+  /// Validate [options], reporting any errors to the given [reporter].
+  void validate(ErrorReporter reporter, Map<String, YamlNode> options);
+}