toggling _isAvailable can result in inappropriate locking

[chris-steele]

Subject of the issue/enhancement/features

A custom plugin determines which articles are available based on some criteria. Each of these articles are configured to use trickle. The trickle plugin will set the _isLocked property on the articles and blocks as expected. At some later time all but one of the mentioned articles are set to _isAvailable:false. The article that is set to _isAvailable:true may still retain _isLocked:true. Rendering therefore stops at the article and the first block is not rendered as it should be.

Executing applyLocks does not correct the _isLocked property. Therefore, it is proposed that prior to applyLocks determining which models are locked, the _isLocked property is set to false on all models.

Your environment

• all frameworks, devices and browsers

Steps to reproduce

See above

Expected behaviour

See above

Actual behaviour

See above

[oliverfoster]

Chris:

Just to follow up on this. The solution I've used is to reset the _isLocked status as follows in applyLocks prior to determining _isLocked:

Adapt.course.getAllDescendantModels(true).forEach(siteModel => {
    if (siteModel.get('_isTrickled')) {
      siteModel.setOnChildren('_isLocked', false);
    }
  });

I'm not sure if this is ideal, but I've had success with it where _isAvailable is dynamically set on articles.

[danielghost]

Can confirm I have also seen this as a result of a role selector changing the availability of the first locked model in a page hierarchy. The siteModel updates _isLocked accordingly, but doesn't apply this to its children, so they components remain locked in the PLP. Can be resolved by making https://github.com/adaptlearning/adapt-contrib-trickle/blob/master/js/models.js#L223-L226 into a method which can be run on the siteModel if it isn't found in the locks object, in addition to the subsequentLockingModels. For example:

const setDescendantLocks = ((model, id) => {
  model.getAllDescendantModels().forEach(descendant => {
    const descendantId = descendant.get('_id');
    modelsById[descendantId] = descendant;
    locks[descendantId] = locks[id];
  });
});
if (!locks[id]) setDescendantLocks(siteModel, id);