Make pub lish validation gitignore-aware.

lib/src/validator/pubspec.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.
+
+library pub.validator.pubspec;
+
+import 'dart:async';
+
+import 'package:path/path.dart' as p;
+
+import '../entrypoint.dart';
+import '../validator.dart';
+
+/// Validates that a package's pubspec exists.
+///
+/// In most cases this is clearly true, since pub can't run without a pubspec,
+/// but it's possible that the pubspec is gitignored.
+class PubspecValidator extends Validator {
+  PubspecValidator(Entrypoint entrypoint)
+      : super(entrypoint);
+
+  Future validate() async {
+    var files = entrypoint.root.listFiles(recursive: false, useGitIgnore: true);
+    if (!files.any((file) => p.basename(file) == "pubspec.yaml")) {
+      errors.add("The pubspec is hidden, probably by .gitignore.");
+    }
+  }
+}
+