Validator fails for mustache template variables inside template node

[src-code]

The validator as of v1457721872758 fails when including a mustache template inline, such as in an amp-list. For example, the following markup should be valid:

<script async custom-template="amp-mustache" src="https://cdn.ampproject.org/v0/amp-mustache-0.1.js"></script>
...
<amp-list src="https://www.example.com/amp/feed?RANDOM" width="auto" height="200" layout="fixed-height">
  <template type="amp-mustache">
    <amp-img src="{{image.url}}" width={{image.width}} height={{image.height}}></amp-img>
  </template>
</amp-list>

The validator produces the following error:

The attribute 'width' in tag 'amp-img' is set to the invalid value '{{image.width}}'.

cc @dvoytenko @Gregable

[Gregable]

I can reproduce. The issue is not new and is specific to the tag layout calculation which handles width/height in a different way that most attributes. src is a non-issue, for example. This is a little tricky because it's impossible to determine if layout is legal in the presence of mustache template variables.

[dvoytenko]

@Gregable I see. In this case, we have to skip this part of validation in template. Perhaps to reduce the negative impact, we can only skip it when width/height/layout and other related values use expressions in them.

[Gregable]

Agreed.

[rudygalfi]

Is there an open PR for this?

[Gregable]

Not yet.

[rudygalfi]

OK, moving to next milestone. Thanks for the update!

[rudygalfi]

@Gregable ping? Should we roll into next sprint or into backlog?

[Gregable]

This one is 'done', I'm working on releasing it to github as we 'speak'.

[Gregable]

This will go live to in-browser validation next week most likely.

[Gregable]

This is live everywhere.