pushing polymorphic records to store only keeps last subtype from hasMany inverse

[danielspaniel]

This is alittle bit hard to explain but the twiddle shows it.

If you have a model A that hasMany of a polymorphic type B
( and lets say we have subtypes B1, B2 ).

When you push polymorphic record B1 that is associated to A,
then this first record B1 is correctly added to the A's hasMany list.
If you push another B1 type record then that is added correctly.
As soon as you switch B types to, let's say B2, then B2 is added but the previous B1's are removed,
and now the hasMany will only accept B2 subtypes.

This twiddle shows the issue:

https://ember-twiddle.com/df81a058c787d97db31366f939a01591?openFiles=routes.application.js%2C

So, as long as you push the same polymorphic type, everything works fine.
If you push a different polymorphic record than the first, it clears the previous subtypes in the hasMany array and adds new one, and will now ONLY allow this new type in the array.
If you use createRecord everything works fine.

Looks like the reason createRecord works is because it takes a different path for adding it's data and relationships than push does. Push is not initializing the relationship right away ( waits for you to do a call like B1.get(A-relationship).
That means that if you say A.get(B-relationship) will always be not quite ready ( with push ). Seems like there is over optimization going on because the behaviour should be same for create or push ... I reckon.

[BryanCrotaz]

I think I'm seeing the same thing in #5267

[BryanCrotaz]

Try my PR #5268 and see if it fixes the problem?