The defaultval flag is an internal flag, so should be called _defaultval. Luckily very little outside of data_smart even refers to it - and generally to ignore it - so this should be fairly simple.
Created attachment 2245 [details] Something like this Breaking convention by putting a patch in bugzilla :) Something like this should work - change the flag name in bitbake, and remove it from everywhere else.
Patches on oe-core and bitbake lists.
Merged in bitbake 2800958dadaa5c055ba21d52c98d842d360f0785