ModelFragments needs to refactor its Fragment state machine for EmberData 3.28+

[runspired]

currentState on DS.Model is now derived heuristically, so setting it to our own state machine will no longer affect any of the state flags on Fragments that we are inheriting from DS.Model. Given that state transitions in ember-data aren't guaranteed and will likely be removed in 4.0 codepaths, we should rewrite our state machine to similarly derive the state.

Potentially we can simply stop adding our own state machine entirely and instead rely on our RecordData implementation to feed the correct info to EmberData's heuristics.

The practical effects of this include for instance a new fragment (e.g. store.createFragment('name')) being in the loaded-but-dirty instead of the isNew state.

[VincentMolinie]

I do have a lot of issue linked to the state on ember-data@3.28.7. Do you know what need to be done ? It's a little bit blocking for me 😅 so I could help 😄

[VincentMolinie]

I actually get those errors:

• cannot get property isNew of undefined
• cannot get property isDeleted of undefined
• 'currentState' is a reserved property name on instances of classes extending Model.

I have all those errors only in my test so far 🤔 .
I'm just creating a model that includes an array of string.
The first 2 points are due to the facts that currentState is undefined in that case 🤔.
If I just change the condition in fragmentDidDirty and fragmentDidReset to handle the undefined currentState I then get the third error.

[VincentMolinie]

Okey I digged a little bit further.
The currentState is undefined and stay undefined because we are accessing isNew and isDeleted before the model is even setup. This happen during the setupFragmentData it seems.

I updated on my side the fragmentDidReset and fragmentDidDirty to something like this and it seems to work so far 🤔

if (record.___recordState && !record.currentState.isNew)

[VincentMolinie]

I did a little PR to fix my issue: #428

[arthur5005]

@runspired does @VincentMolinie fix go far enough to address this issue, i.e. will ModelFragments work on 3.28.x/4.x going forward?

[runspired]

The fix we want is @dwickern's in #417

[VincentMolinie]

Should this issue be closed @runspired 🤔 ?

[knownasilya]

I believe so