The transformer makes an attempt to invoke `null.parent`. about reflectable.dart

[eernstg]

This is a bug in the reflectable transformer, it should of course never make an attempt to call parent on null. There is just one place where it calls parent, and it hasn't been changed since version 0.1.1. It would be very helpful if you could provide source code that causes this failure to occur!

The other topic is whether the transformer should continue to transform other entry points when the transformation of any given entry point fails with an transformer detected error in the program under transformation. I separated that out as a new issue #39.

[eernstg]

Adjusted the title, now that this issue is only about the null.parent bug.

[zoechi]

Sorry, I guess I won't be able to reproduce.

I'm working on porting PolymerElements from Polymer.js to Poylmer.dart
There are quite a few entry points where the boilerplate is generated from a script which crawles GitHub organizations for repositories generates an entry page for each repository and copies some HTML and JS from GitHub into the generated Dart files.
See https://github.com/bwu-dart-contributing/polymer_elements/tree/demo2/demo/web

I also generated an entry_point line for each web_components and reflectable transformer and copied these into the pubspec.yaml file, which led to halfway valid generated code for a lot of entry-points.

I then fixed one of the entry-points and tried to load it in Dartium which led to "unrelated" errors because the were from entry-points I didn't care about yet. I didn't expect this specific error to be of interest to you.
The generating script changed a lot since then an produces much better code now by default. I didn't check in all the changes in between.

[eernstg]

OK, thanks for the quick reaction!

[zoechi]

Seems not to difficult to reproduce after all. I just encountered it again.
This is the source https://github.com/bwu-dart-playground/polymer_elements_parent

• clone the repo
• change to the demo subdirectory
• run pub get
• launch demo/web/iron_validatable_behavior/index.html from WebStorm
  • or load http://localhost:8080/iron_validatable_behavior/index.html (I guess this would be the URL if you want to load it without WebStorm)

[eernstg]

OK, thanks!

Apparently, it is possible for an analyzer FieldElement about a field on an instance of a subclass of Element from 'dart:html' to have null as its syntax (node). I've landed a commit (5725ef1) that protects against crashing in such a situation.