ember-data-model-fragments: Model fragments broken against Ember Data 3.28

Here’s a quick workaround,

import FragmentTransform from 'ember-data-model-fragments/transforms/fragment';
import FragmentArrayTransform from 'ember-data-model-fragments/transforms/fragment-array';

FragmentTransform.reopen({
  serialize(snapshot) {
    return this._super(snapshot?._createSnapshot?.() ?? snapshot);
  },
});

FragmentArrayTransform.reopen({
  serialize(snapshots) {
    return this._super(snapshots?._createSnapshot?.() ?? snapshots);
  },
});

As @lowski pointed out, the problem may be that before 3.28 the Snapshot for serialization is created by calling InternalModel.createSnapshot which is overridden in ext.js to recursively transform Fragments to Snapshots. In 3.28 the Snapshot for serialization is created by calling new Snapshot() directly instead so Fragments are no longer transformed to Snapshots.

I was able to dirty fix it by calling createSnapshot manually in the FragmentTransform.serialize method :

// transforms/fragment.js

serialize: function serializeFragment(snapshot) {
  if (!snapshot) {
    return null;
  }

  // Dirty fix for Ember Data 3.28
  // snapshot may be a Fragment instead of a Snapshot
  if (typeof snapshot._createSnapshot === 'function') {
    snapshot = snapshot._createSnapshot();
  }

  let store = this.store;
  let serializer = store.serializerFor(snapshot.modelName);

  return serializer.serialize(snapshot);
},

// transforms/fragment-array.js

serialize: function serializeFragmentArray(snapshots) {
  if (!snapshots) {
    return null;
  }

  // Dirty fix for Ember Data 3.28
  // snapshots may be a Fragment instead of an Array<Snapshot>
  if (typeof snapshots._createSnapshot === 'function') {
    snapshots = snapshots._createSnapshot();
  }

  let store = this.store;

  return snapshots.map(snapshot => {
    let serializer = store.serializerFor(snapshot.modelName);
    return serializer.serialize(snapshot);
  });
}

There is probably a better way / place to do this.

@knownasilya there are already failing tests on existing test suite related to that error:

https://github.com/adopted-ember-addons/ember-data-model-fragments/runs/3613005831?check_suite_focus=true#step:7:641 https://github.com/adopted-ember-addons/ember-data-model-fragments/runs/3613005831?check_suite_focus=true#step:7:456

The right way to do this is to store the serialized form in the fragment RecordData, no private apis would be necessary then.

@knownasilya @kevinkucharczyk I believe found the culprit: CoreStore in 3.27.1 doesn’t have REQUEST_SERVICE flag enabled (in 3.28.1 it’s already on) so scheduleSave relies on pendingSave queue (which uses internalModel.createSnapshot(options) to create model’s snapshots):

let snapshot = internalModel.createSnapshot(options);
this._pendingSave.push({
  snapshot: snapshot,
  resolver: resolver,
});

emberBackburner.scheduleOnce('actions', this, this.flushPendingSave);

In 3.28.1 scheduleSave goes through fetchManager (via if (REQUEST_SERVICE) { ... } conditional) and it uses Snapshot constructor to build model’s snapshot:

let snapshot = new Snapshot(options, identifier, this._store);

For some reason, fragments are not correctly converted to snapshots in this case. I don’t know if it’s bug or desired behavior.

I’m not an Ember expert by any means so I’m not sure what’s the most appropriate solution but in 3.28.1 serializer.serialize(snapshot) operates on Fragment instead of Snapshot. I don’t know what consequences it might have 🤷 .

I merged that fix, so master should work as well. Will try to research a bit more and see if there is a better solution.

@knownasilya I’ve just tested it on my project and #407 doesn’t fix this issue - now I’m getting a following error:

Error: Assertion Failed: The `attr` method is not available on Model, a Snapshot was probably expected. Are you passing a Model instead of a Snapshot to your serializer?

@kevinkucharczyk can you check latest master on your project as well?

I can confirm this. I just bumped my app to 3.28.0 and was bitten by the same error.