Fix/empty layers

[TrevorBurgoyne]

Fix/empty layers

Description

• Fix bug where empty polygon layers could be included in a submit_button hook payload.

Testing

A user of ULabel found that empty [] layers were occasionally present in the polygon annotations provided by the ULabel submit button hook. I have been unable to get this to occur during normal operation of ULabel, but instead have added a fix to prevent these empty layers from being present when delivered through the submit button.

By adding an empty [] layer to the resume_from.html in the demo, I confirmed that these get removed on load into ULabel when they are loaded in via ULabelAnnotation.from_json(). So now we perform the same operation when preparing annotations to be delivered when a submit button hook is called.

I confirmed that this removes empty layers by adding the following code to index.js at line 353:

if (cand["id"] == "d0f9b427-123d-46c0-a131-84db3f002b6f") {
    cand["spatial_payload"].push([]);
    console.log(cand["spatial_payload"]);
}

When running the demo resume_from.html, this forcibly adds an empty layer to one of the annotations after it has been initialized. I confirmed that pressing the Submit button successfully removes the empty layer in the delivered annotations.

PR Checklist

• Merged latest main
• Version number in package.json has been bumped since last release
• Version numbers match between package package.json and src/version.js
• Ran npm install and npm run build AFTER bumping the version number
• Updated documentation if necessary (currently just in api_spec.md)
• Added changes to changelog.md

Breaking API Changes

no thanks

[TrevorBurgoyne]

Here we ensure that the annotations being delivered are still valid ULabelAnnotation objects

[joshua-dean]

Seems good, although that line certainly make me want to write some annotation getters...

[joshua-dean]

(Covered in #198)

[TrevorBurgoyne]

I never ran into any errors with the loader but just to be safe i figured id add it

[joshua-dean]

LGTM