Collect statistics about keys in pubspec.yaml files. (#1526)

* Collect statistics about keys in pubspec.yaml files.

* k -> keyAsString

Author: isoos

app/bin/tools/pubspec_stats.dart

@@ -0,0 +1,36 @@
+// Copyright (c) 2018, 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.
+
+import 'dart:async';
+
+import 'package:appengine/appengine.dart';
+import 'package:gcloud/db.dart';
+
+import 'package:pub_dartlang_org/frontend/models.dart';
+import 'package:pub_dartlang_org/frontend/service_utils.dart';
+
+Future main(List<String> args) async {
+  useLoggingPackageAdaptor();
+  await withProdServices(() async {
+    final counts = <String, int>{};
+
+    int index = 0;
+    final query = dbService.query(PackageVersion);
+    await for (PackageVersion pv in query.run().cast()) {
+      index++;
+      if (index % 100 == 0) {
+        print('$index - ${pv.package} ${pv.version}');
+      }
+      pv.pubspec.asJson.keys.forEach((key) {
+        final keyAsString = key.toString();
+        counts[keyAsString] = (counts[keyAsString] ?? 0) + 1;
+      });
+    }
+
+    final sortedKeys = counts.keys.toList()..sort();
+    for (String key in sortedKeys) {
+      print('$key: ${counts[key]}');
+    }
+  });
+}