Implement LibraryMirror.metadata.

dart/tests/lib/mirrors/metadata_test.dart

+// Copyright (c) 2013, 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.
+
+@fisk @symbol
+library test.metadata_test;
+
+import 'dart:mirrors';
+
+const fisk = 'a metadata string';
+
+const symbol = const Symbol('fisk');
+
+main() {
+  MirrorSystem mirrors = currentMirrorSystem();
+  LibraryMirror library =
+      mirrors.findLibrary(const Symbol('test.metadata_test')).first;

[kasperl, 2013/05/29 06:25:06]

Should findLibrary be renamed? It would be easier to understand if it was called
findLibraries.

[ahe, 2013/05/29 06:40:28]

That's a good suggestion.

[ahe, 2013/05/30 11:41:15]

Filed bug: http://dartbug.com/10958

+  List metadata = library.metadata.map((m) => m.reflectee).toList();
+  if (metadata.length != 2) {
+    throw 'Expected two pieces of metadata on library';
+  }
+  if (!metadata.contains(fisk)) {
+    throw '$metadata does not contain "$fisk"';
+  }
+  if (!metadata.contains(symbol)) {
+    throw '$metadata does not contain "$symbol"';
+  }
+  if (MirrorSystem.getName(symbol) != 'fisk') {
+    // This happened in dart2js due to how early library metadata is

[kasperl, 2013/05/29 06:25:06]

This happened? I guess this is a regression test for an earlier buggy
implementation in dart2js? Maybe update the comment to reflect that.

[ahe, 2013/05/29 06:40:28]

It is not really a regression test.  I inspected the output and noticed that the
wrong constant had been built as the redirecting factory constructor hadn't been
resolved yet.  Without the changes to compile_time_constants.dart, this test
fails, but the rest passes.

+    // computed.
+    throw 'Bad constant: $symbol';
+  }
+  print(metadata);

[kasperl, 2013/05/29 06:25:06]

Intentional?

[ahe, 2013/05/29 06:40:28]

Yeah.  I distrust tests that don't produce output.  I've been burned too many
times :-)

+}