this.push doesn't notify changes to computed property

[arthurgubaidullin]

I have array property and computed property that depend on array. When i use this.push() method, my computed property doesn't recompute.

[ebidel]

Please include a jsbin that repos the issue.

[chiefcll]

We're seeing something similar... We think its related to #2007 - The changes now send notification changes of array.#1.prop rather than array.1.prop - so if you set up any observer on that property without the # it won't get called.

[samccone]

I think this is also related
#2556

[chiefcll]

http://plnkr.co/edit/5UW4wKanTR5v9Z7P79P3?p=preview

[ebidel]

Using https://rawgit.com/Polymer/polymer/v1.1.5/polymer.html in that demo, I see two console logs
Using https://rawgit.com/Polymer/polymer/v1.2.0/polymer.html, I see one :(

This is a regression.

[ebidel]

So I'm told from @kevinpschaaf this was never supposed to work. It's even documented as such: https://www.polymer-project.org/1.0/docs/devguide/data-binding.html#array-binding.

binding to or observing array indices is not supported. i.e. observer: [ 'myArrayChanged(myArray.1.value)' ] and {{myArray.1.value}}

that was never intended to be supported, so the fact that it changed is a result of relying on an unsupported feature

reason is that all path notifications for arrays are done as keys; observing an index (i.e. as an observer dep or binding) would require reverse lookup from key back to index, which is an O(n) operation for each

[ebidel]

Closing as per the observation in the previous comment.

[arthurgubaidullin]

@ebidel please see: http://plnkr.co/edit/iNVTULU8w4bXxjyxunsd?p=preview

[kevinpschaaf]

@lapteuh computeMyComputedArray(myArray) only re-computes when the myArray reference itself changes. To re-compute on any deep change to myArray, use computeMyComputedArray(myArray.*):

http://plnkr.co/edit/348Amty1bSJMEZX5g4dy?p=preview

[arthurgubaidullin]

@kevinpschaaf thanks.