Data: Loading a previously unloaded record doesn't update relationships

[workmanw]

Unfortunately I've hit another unloadRecord bug. When I unload a record that is on the belongsTo side of a one-to-many it is correctly removed from the hasMany array. However when I push that same record back into the store, it is not added back to the hasMany array.

Ember: 2.14.1
Ember-Data: 2.14.10

Reproduction repo: workmanw/unload-relationships-bug.
Code: app/controllers/index.js.
Live example: https://workmanw.github.io/unload-relationships-bug
Failing Test: #5137

To reproduce:
1) Load Record
2) Unload Record
3) Load Record again.

You'll notice that the "All Comments" section shows the record was reloaded (re-pushed) into the store, however the relationship on the post is not updated to reflect this.

One note here, I'm using async: false on this relationship. If I use async: true it creates a crash on unload.

[workmanw]

Just a little more poking around.

This functionality last worked correctly in ember-data-2.12.2. With ember-data-2.13.0 it was not possible to unload records and update relationships. That was fixed in ember-data-2.14.7 via #5097, however this issue was left lingering.

[stefanpenner]

@workmanw thanks for the failing test

[workmanw]

You're welcome! Let me know if there is anything else I can do to help.

[stefanpenner]

@workmanw mind adding another test for:

If I use async: true it creates a crash on unload.

That way we can fix both these issues and ensure they don't come back

[stefanpenner]

Unfortunately I've hit another unloadRecord bug.

ooo my favorite ... :trollface:

[workmanw]

@stefanpenner Sure thing, I'll add another test now.

[workmanw]

@stefanpenner Actually, as I'm trying to write another test, I'm realizing that it may not be a valid use case. The reason is when you unload an async relationship, it still leaves the hasMany setup so that it can fetch it again if needed. Consider this (a little pseudo code):

let adam = store.peekRecord('person', 1);
adam.hasMany('boats').ids();   //  '[]'

store.push(/* a boat for adam */);
adam.hasMany('boats').ids();   // '[20]';

store.unloadRecord('boat', 20);
adam.hasMany('boats').ids();   // '[20]';

As you can see, just unloading the boat, no long tears down the relationship because it's async (which logically makes sense to me).

---

As for the error I mentioned, it turns out this was a different problem altogether. TL;DR; if I unload a model, then try to refetch it via it's async relationship and that fails, it throws a crash because this.record is now null. Here is a stack:

TypeError: Cannot read property 'eachAttribute' of null
    at new Snapshot (-private.js:5091)
    at InternalModel.createSnapshot (-private.js:6930)
    at _find (-private.js:8695)
    at Class._fetchRecord (-private.js:10670)
    at _fetchRecord (-private.js:10731)
    at Class._flushPendingFetchForType (-private.js:10830)
    at cb (ember.debug.js:27921)
    at OrderedSet.forEach (ember.debug.js:27728)
    at MapWithDefault.forEach (ember.debug.js:27929)
    at Class.flushAllPendingFetches (-private.js:10712)

I think this should be written up separately.

[stefanpenner]

As you can see, just unloading the boat, no long tears down the relationship because it's async (which logically makes sense to me).

👍

I think this should be written up separately.

👍

[stefanpenner]

I've identified in broad strokes the issue, but haven't isolated the exact problem yet.

The issue as I see it so far, is if an internalModel is resurrected (unloaded, but still retained by an async relationship) \w updated relationship info, that relationship info isn't propagated to the inverse (in the case, person.boats is not updated).

I'll try to find more time later today to investigate further... I'll need to talk to @hjdivad, see what makes the most sense short-term, as we have a future path forward.

---

On a positive note, I found several other things while debugging this:

• https://github.com/emberjs/data/pull/5153
• https://github.com/emberjs/data/pull/5151
• https://github.com/emberjs/data/pull/5150

[workmanw]

@stefanpenner Is there anything I can do to help here? I know you're working hard on it and don't want to rush you. If I can't come up with a workaround for this, I'm faced with downgrading ember-data to 2.12 again for our next release.

[lolmaus]

@workmanw Can you please update the demo to the latest Ember CLI, Ember & Ember Data? That would indicate that the issue is not covered by bugfixes from ED 2.15.

[workmanw]

@lolmaus @stefanpenner -- Yes, this is still an issue with ember-data-2.15. I've updated my repo and my live example to use latest of Ember, Ember CLI and Ember Data.

Any help here would be greatly appreciated. Our application is stuck back on 2.12 because of all these unloadRecord issues.

[workmanw]

@stefanpenner et al -- Is there anything that can be done to move this forward? I'm sorry to be a pest here, but this has locked us 3 releases behind (soon to be 4). We've explored every work around we can think of and can't seem to find a way to stay up to date. I hate feeling left behind, our ember-try tests have been failing since April, being in this state leaves us feeling disconnected from the whole community.

[vvainio]

Our fairly large Ember app is facing the same issue, and this has been a blocker for the past few releases as @workmanw described. I would appreciate any information whether this issue is being worked on, otherwise we'll need to try coming up with a workaround.

[eduardbaitinger]

Also facing the same problems with unloading records in our enterprise ember apps and therefore stuck on ember data 2.12 :(

[lolmaus]

@igorT Woah, that's a nice surprise! :bowing_man:

I wonder if it fixes other issues as well. There are several closely related ones.

[hjdivad]

@lolmaus please report issues and tag me if you're still seeing unloadRecord related regressions.

There's an outstanding issue on that PR that still needs investigating, although it's related to filtering record arrays and not relationships.