Re: 2.6 bug: kconfig implementation doesn't match the spec

From: Adrian Bunk (bunk_at_fs.tum.de)
Date: 08/08/03

  • Next message: Adrian Bunk: "Re: 2.6.0-test2 won't compile" 
    Date:	Fri, 8 Aug 2003 19:47:36 +0200
To: Roman Zippel <zippel@linux-m68k.org>

    On Fri, Aug 08, 2003 at 05:16:09PM +0200, Roman Zippel wrote:
    > Hi,
    >
    > On Fri, 8 Aug 2003, Adrian Bunk wrote:
    >
    > > An example:
    > >
    > > config FOO
    > > tristate
    > > default m
    > >
    > > config BAR
    > > tristate
    > > default y if !FOO
    > > default n
    > >
    > >
    > > According to the kconfig spec BAR should be y, but the implementation in
    > > 2.6.0-mm5 sets BAR to n.
    >
    > You probably forgot to set MODULES, tristate behaves like bool in this
    > case and FOO becomes 'y' and '!FOO' is 'n'.

    No, this is with CONFIG_MODULES=y.

    Let me give another example where the kconfig implementation is
    completely broken (BTW: again with CONFIG_MODULES=y):

    According to your language definition,
      m && !m
    evaluates to "m" (it sounds a bit strange but follows directly from
    rules (5) and (7) together with the interpretation of "m" as 1 as
    explained in the section "Menu dependencies" of
    Documentation/kbuild/kconfig-language.txt).

    Let's take the following Kconfig snippet:

    config MOD
            tristate
            default m

    config TEST8
            tristate
            default MOD && !MOD

    config TEST9
            tristate
            default m && !m

    With the explations above it's obvious both TEST8 and TEST9 should be
    "m", but the current 2.6 kconfig implementation says:

    # CONFIG_TEST8 is not set
    CONFIG_TEST9=y

    That's not only different from the expected result directly derived from
    the language definition, it also gives two completely different results
    for the same expression!

    > bye, Roman

    cu
    Adrian 

    -- 
       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed
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