On Thu, 2011-08-11 at 17:24 +0200, Michal Marek wrote:

One of my use cases for all.config is

$ cp .../older-working-config all.config
$ make KCONFIG_ALLCONFIG=1 allmodconfig

i.e. reuse what is possible from an older config and enable all new
options. Surely it sometimes results in suboptimal configuration with
unwanted debug options enabled, but most of the time it works. I won't
be happy if you make it hard fail because of renamed or removed config
options. 

On the other hand, 'make CONFIG_FOO=y oldconfig' probably *should* fail.
Perhaps it should set what it *can*, if you try to set multiple options
at once — but if it can't set all of them, it should exit with failure
status... which will mean that no subsequent build target will happen.

-- 
dwmw2