array_proxy.js: cannot read property 'length' of undefined

[srsgores]

Upon upgrading a legacy ember app, the model is unable to resolve to ArrayProxy:

array_proxy.js:155 Uncaught TypeError: Cannot set property 'length' of undefined at Class.objectAt (array_proxy.js:155) at objectAt (metal.js:1300) at EmberArrayIterator.valueFor (glimmer.js:2333) at EmberArrayIterator.next (glimmer.js:2290) at ReferenceIterator.next (reference.js:373) at Object.APPEND_OPCODES.add [as evaluate] (runtime.js:1288) at AppendOpcodes.evaluate (runtime.js:39) at LowLevelVM.evaluateSyscall (runtime.js:2179) at LowLevelVM.evaluateInner (runtime.js:2153) at LowLevelVM.evaluateOuter (runtime.js:2146)

The error occurs on this line:

let length = this._objects.length = (0, _metal.get)(arrangedContent, 'length');

As here.

By the looks of it, some models will not have prepopulated with this.objects, so we should check that this array is also undefined as opposed to just null:

if (this._objects === null || this._objects === undefined) {
    this._objects = [];
}

• Ember: 3.6.1
• Ember data: 3.6.0

[rwjblue]

Can you provide a demo / reproduction?

[srsgores]

@rwjblue: I can PM you a link. Leave your contact details

[srsgores]

Which e-mail am I sending the repro to?

[pixelhandler]

@srsgores Often we use https://ember-twiddle.com/ or if that doesn't work for your use case a sample repository and link to it here. The goal with a reproduction of the issue is to demonstrate the bug, and in many cases when trying to create a simple example we find out where the bug is, either in our codebase or in some cases in the framework.

Also, sharing a simple reproduction in code helps others address a problematic use case. Can you re-create the issue using ember-twiddle?

[locks]

Closing due to lack of reproduction. If you are able to publish the reproduction, or if you encounter the same bug for newer versions of Ember, please let us know!