Property files and property names and duplicate properties.

[Cantor, Scott]

> I should close by saying that this really is an edge condition in 3.4 and the
> badness is limited to already broken installs.  There are only a handful of
> properties and we can pretty much guarantee that the names will never
> collapse.  So the only issue would be if someone had managed to add a
> property with a new (about to be valid) name but an invalid value to the end of
> the property file.

Yeah, I think it assumes a case where two separate older versions of a given property appear. I would think warning and failing are reasonable.

Maybe it's simpler to just implement a pre-check that checks for mutually exclusive attributes up front.
 
-- Scott