Verify that all elements have a parent (#31)

Fixes flutter#15

Author: Harry Terkelsen

bin/debug_info.dart

@@ -27,6 +27,7 @@ main(args) async {
   }
 
   validateSize(info, debugLibName);
+  validateParents(info);
   compareGraphs(info);
   verifyDeps(info);
 }
@@ -74,6 +75,30 @@ validateSize(AllInfo info, String debugLibName) {
   }
 }
 
+/// Validates that every element in the model has a parent (except libraries).
+validateParents(AllInfo info) {
+  final parentlessInfos = new Set<Info>();
+
+  failIfNoParents(List<Info> infos) {
+    for (var info in infos) {
+      if (info.parent == null) {
+        parentlessInfos.add(info);
+      }
+    }
+  }
+
+  failIfNoParents(info.functions);
+  failIfNoParents(info.typedefs);
+  failIfNoParents(info.classes);
+  failIfNoParents(info.fields);
+  failIfNoParents(info.closures);
+  if (parentlessInfos.isEmpty) {
+    _pass('all elements have a parent');
+  } else {
+    _fail('${parentlessInfos.length} elements have no parent');
+  }
+}
+
 class _SizeTracker extends RecursiveInfoVisitor {
   /// A library name for which to print debugging information (if not null).
   final String _debugLibName;

pubspec.yaml

@@ -1,5 +1,5 @@
 name: dart2js_info
-version: 0.5.6+2
+version: 0.5.6+3
 description: >
   Libraries and tools to process data produced when running dart2js with
   --dump-info.