Re: RFC: kconfig select warnings bogus?

Stefan Richter
2007-05-20T20:13:41Z

Trent Piepho wrote:
> config A
> bool "A"
>
> config B
> bool "B"
> depends on A
>
> config C
> bool "C"
> select B
>
> In this case, it's possible to turn C on and A off. B will be on, even
> though it depends on A and A is off.
>
> The kconfig docs say that "B.. depends on A" sets the maximum value of B
> to be that of A. Since A=0, the max value of B is 0.
>
> The kconfig docs also say that "C.. select B" sets the minimum value of B
> to be that of C. Since C=2, the minimum value of B is 2.
>
> So we have B>=2 and B<=0, which is obviously impossible. Yet *config has
> no problem with this, and will set B=2 even the 'depends' means B must be
> 0. It seems like "select" will override any other dependencies.

If that's so, then we have /a/ an incomplete definition of the Kconfig
language (what is supposed to happen if "select" attempts to set an
impossible value?) and /b/ a bug in the make xyzconfig programs (they
generate invalid configs).
--
Stefan Richter
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