As discussion on
DM-4692 and in various HipChat rooms, it's too easy for camera-level config override files to contain many options that don't actually change anything, because they simply override the defaults with the same default values. To aid in tracking these down and removing them, we should have an option in which CmdLineTask s (delegating to pex_config) refuse or warn about overrides that have no effect.
We should probably not make failing on do-nothing overrides the default behavior, but we could consider making warning the default behavior. Mostly, I think it's important just to be able to find such options when wanted.