JSONTreebinding changing on every property in model

[igzThomasFrischholz]

What is the issue and how can we reproduce it?

1. Bind a tree in a JSONModel to a sub property (e.g. /nestedItems)
2. Change a different property in the model (e.g. /somethingCompletelyDifferent)

Error:

Observe the tree binding also firing the change event.

Expected behavior:

Tree binding only firing change when any child or child property of /nestedItems changed

Disclaimer:

Maybe i am understanding something wrong but this behavior does not look like its intended or in any case useful
I have not tested if this is JSONModel specific or if other model implementations are affected as well

JS Bin snippet reproducing the bug: https://jsbin.com/jakewodene/4/edit?js,output

When running the snippet you should see an alert confirming that the tree binding has changed

Which OpenUI5 version is your project targeting?

1.139.0

Is the issue device- or browser-specific?

No.
Tested on Chrome, Edge and Firefox

Confirmation

• I have searched the existing issues and reviewed the relevant documentation as well as the API reference.
• I am not disclosing any internal or sensitive information.

[pksinsik]

Hello @igzThomasFrischholz,

Thank you for sharing this finding. I've created the internal incident DINC0640723. The status of the issue will be updated here in github.

[1110101]

Hi @igzThomasFrischholz,

I agree that there should be no change event fired to "/somethingCompletelyDifferent" if its not bound by the JSONTreeBinding. We are working on a fix internally to address this. So that only a change even is fired if the bound data is changed.

Independently of that fix which we will provide: could you maybe describe the issue which you encounter in your "real" application?

[igzThomasFrischholz]

We are using SAPUI5 mainly as a standard Web-Framework for the SAP integrated applications we create in our team. (not SAP as backend but ASP.NET backend communicating with SAP, hence the use of mostly json models).

I extended sap.m.Tree and sap.m.CustomTreeItem to support hover events on the items. The hovered item would set a marker in another property of the same model to allow for highlighting elsewhere in the application. When using this i noticed the tree was extensivly rerendering on every hover which caused not only the hover events but also the normal click events on the items to fail sporadically or fire too often. The fix for me for now is to write the data to a completly separate model until fixed.