[mdv] getTeminatorAt recurses infinitely if template is its own terminator

pkg/mdv/lib/src/template_iterator.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.
 
 part of mdv;
 
 // This code is a port of Model-Driven-Views:
 // https://github.com/polymer-project/mdv
 // The code mostly comes from src/template_element.js
 
@@ skipping 214 matching lines @@
     }
 
     int addedCount = iteratedValue.length;
     var removedCount = oldValue is List ? (oldValue as List).length : 0;
     if (addedCount == 0 && removedCount == 0) return; // nothing to do.
 
     _handleChanges([new ListChangeRecord(0, addedCount: addedCount,
         removedCount: removedCount)]);
   }
 
   Node getTerminatorAt(int index) {

[justinfagnani, 2013/07/23 19:59:40]

for my own education, what's a terminator?

[Jennifer Messerly, 2013/07/23 20:13:00]

you know almost as much as I do :)

from the code, each terminator is the last node in the expanded fragment. so if
I assign a 2-item model to: <template
repeat><div>foo</div><div>bar</div><template>, the two "bar" divs will be the
terminators.

     if (index == -1) return _templateElement;
     var terminator = terminators[index];
-    if (terminator is Element && (terminator as Element).isTemplate) {
+    if (terminator is Element && (terminator as Element).isTemplate &&
+        !identical(terminator, _templateElement)) {
       var subIterator = _mdv(terminator)._templateIterator;
       if (subIterator != null) {
         return subIterator.getTerminatorAt(subIterator.terminators.length - 1);
       }
     }
 
     return terminator;
   }
 
   void insertInstanceAt(int index, List<Node> instanceNodes) {
@@ skipping 11 matching lines @@
   }
 
   List<Node> extractInstanceAt(int index) {
     var instanceNodes = <Node>[];
     var previousTerminator = getTerminatorAt(index - 1);
     var terminator = getTerminatorAt(index);
     terminators.removeAt(index);
 
     var parent = _templateElement.parentNode;
     while (terminator != previousTerminator) {
-      var node = terminator;
-      terminator = node.previousNode;
+      var node = previousTerminator.nextNode;
+      if (node == terminator) terminator = previousTerminator;
       node.remove();
       instanceNodes.add(node);
     }
     return instanceNodes;
   }
 
   getInstanceModel(model, String syntax) {
     var delegate = TemplateElement.syntax[syntax];
     if (delegate != null) {
       return delegate.getInstanceModel(_templateElement, model);
@@ skipping 25 matching lines @@
       return;
     }
 
     // TODO(jmesserly): IdentityMap matches JS semantics, but it's O(N) right
     // now. See http://dartbug.com/4161.
     var instanceCache = new IdentityMap();
     var removeDelta = 0;
     for (var splice in splices) {
       for (int i = 0; i < splice.removedCount; i++) {
         var instanceNodes = extractInstanceAt(splice.index + removeDelta);
+        if (instanceNodes.length == 0) continue;
         var model = _mdv(instanceNodes.first)._templateInstance.model;
         instanceCache[model] = instanceNodes;
       }
 
       removeDelta -= splice.addedCount;
     }
 
     for (var splice in splices) {
       for (var addIndex = splice.index;
           addIndex < splice.index + splice.addedCount;
@@ skipping 35 matching lines @@
         nodeExt._templateIterator = null;
       }
     }
 
     _nodeOrCustom(node).unbindAll();
     for (var c = node.firstChild; c != null; c = c.nextNode) {
       _unbindAllRecursively(c);
     }
   }
 }