A recent series of changes to OE-Core starting with [1] removed many sites where a FuncFailed exception is raised. We should add docstring to the FuncFailed class to explain its correct usage. We may also want to add something to the BitBake user manual. 1. http://git.openembedded.org/openembedded-core/commit/?id=9635af9785509a39c1ac2509740d46276119a0ca
The bitbake manual already discusses use of FuncFailed: https://www.yoctoproject.org/docs/latest/bitbake-user-manual/bitbake-user-manual.html#bitbake-style-python-functions-versus-python-functions