Remove MODEL_FACTORY_INJECTIONS

[wycats]

What are the blockers for normalizing model instantiation to be like all other injections?

[stefanpenner]

• [ ] ember-data stores stuff on the constructors
• [ ] our current subclassing mechanism for injectable factories breaks ember-data's current polymorphic setup (and potentially reasonable user-code)
• [ ] maybe transition to a specialized factory object (but this is theoretically breaking, and requires much changing to the view layer. Specifically this.createChildView mega morphic signature)
• [ ] ...

i'll list more and a migration plan as I have time.

[fivetanley]

ember-data stores stuff on the constructors

I feel like this could be actionable immediately (I'm saying I could try to do it) if we put stuff on the (Ember, not Ember Data) meta for the class. Is that a valid assumption?

[stefanpenner]

I think its tricky since it cache various relationship things as CP's on the constructor. This caching is important re: perf, but also pollutes the constructor. This is fixed by todays EXTENDPROTOTYPES = true, as we get a new subclass each test run. But unfortunately `EXTEND...` breaks the current implementation of polymorphism

[wycats]

@fivetanley Can we make sure we discuss an alternative for storing metadata on classes at the next ED meeting?

[tomdale]

Perhaps the factory returned from the container, in addition to having a create() method, could have a constructor property to access the actual class being used to make instances? This is useful for informational/metadata purposes but we can make it clear you shouldn't use it to create instances. (Not sure anyone would be tempted to container.lookupFactory('model:foo').constructor.create() and expect the correct behavior, but…)

[fivetanley]

I've made a note of it and will bring it up next week.

[stefanpenner]

constructor has some meaning in javascript, what about Class.

factoryObject = {
  Class: OriginalClassObject,
  create(attrs) { ... create instance with injections }
};

[tomdale]

@stefanpenner Great point. Uppercase "C" looks a little weird to me—what about lowercase "c" class (should be fine since we use ES3safe) or factory?

[stefanpenner]

@tomdale ya it should be safe with ES3Safe and modern browsers

[igorT]

Currently in ED in a lot of places where we use modelFor(mostly in Serializer/Adapter), we actually want the class not the factory, as we don't instantiate stuff ourselves, just lookup metadata

[stefanpenner]

@igorT @bmac @fivetanley whats the status for ember-data on this one?

[rwjblue]

I believe a bunch of work in ED has been done on this. I'd like to get some feedback from @emberjs/ember-data-contributors...

[stefanpenner]

The remaining work was removing the fact the subclasses are returned from lookup factory. Unfortunately others decided this was for some reason to much of a breaking change during 2.0 transition

[stefanpenner]

https://github.com/emberjs/data/pull/4810 + https://github.com/emberjs/ember.js/pull/14360 together make Ember.MODEL_FACTORY_INJECTIONS have no more power (it not longer does stuff). We likely can't remove it for some time from the blueprints for compatibility with individuals on older versions of ember or ember-data.

cc @chadhietala

[rwjblue]

We can deprecate having it set though. This sets us up for removal at some future point (sometime after 2.16).

[mmun]

MODEL_FACTORY_INJECTIONS was removed in 2.14.