MDG Custom entity refresh on change, Empty custom entity

[ShankarGomare]

Hello SAP Community,

I would like to pass on my experience from a recent upgrading event; I'm documenting it here so that anyone who encounters this particular issue will have a reference and a solution to address it.

In MDG, building a custom entity is a very simple and well-documented process; unfortunately, after our system upgrade, custom entities ceased showing information or maintaining data on changes in NWBC. 

I recreated tones of custom entities and subsequent UIBBs on screen, but their behavior was similar across all custom entities. I checked every component of the GenIL or MDG models, as well as every custom enhancement or handler class.
After spending hours and hours trying to figure out the problem, we discovered that SAP had recently made corrections for performance optimization, one of which was an authorization check on entities. 

The change was applied to standard handler classes, specifically in method "IF_MDG_BS_BP_ACCESS_HANDLER~CHECK_AUTHORITY_BY_ENTITY". This method is now obsolete and all logic is moved under "IF_MDG_BS_BP_ACCESS_HANDLER~CHECK_AUTHORITY_MASS_BY_ENTITY". However, the fix included a warning message in the obsolete method, which caused authority checks to fail, causing data refresh issues on custom entities.

This fix is in SAP Note 3406917.
I hope this helps someone save a lot of time on debugging.

[Shivangi236]

Thanks a lot for sharing this.