<amp-script> must not be empty

[fstanis]

What's the issue?

If <amp-script> is empty (doesn't contain any initial content), then no attempt is made to load it and no error is throws.

How do we reproduce the issue?

<amp-script layout="container" src="/anything.js"></amp-script>

This should either:

• Make an attempt to fetch /anything.js
• Result in runtime error
• Result in validator error

Which AMP version is affected?

1908222134250

[nainar]

This is a developer affordance we should definitely have to set them on the correct path. Marking it as a P1 as such.

[dreamofabear]

I think this is actually due to the amp-script element having a width/height of zero. Such elements are ignored by the resource scheduling system -- layoutCallback() won't be called which initializes the element.

Is there a use case you have in mind for a child-less amp-script? E.g. I can imagine using amp-script as a data layer (using AMP.setState in the JS), though you could just add width=1 height=1 as a workaround.

[samouri]

I think this is actually due to the amp-script element having a width/height of zero. Such elements are ignored by the resource scheduling system -- layoutCallback() won't be called which initializes the element.

I've actually run into this as well and was confused. I was attempting to populate the <amp-script> element completely by the script's js as without having initial contents.

Forcing a nonzero width is fine, but I'd at least expect a dev warning.

[dreamofabear]

We could do that by overriding onLayoutMeasure() or onMeasureChanged() in amp-script.js and warning if the layout box has a zero size and hasn't been laid out.