linux-kernel - Re: [PATCH] kconfig: fix relational operators for bool and tristate symbols

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Date:   Sat, 6 Jan 2018 02:34:02 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Nicolas Pitre <nicolas.pitre@...aro.org>
Cc:     Michal Marek <michal.lkml@...kovi.net>,
        Jan Beulich <JBeulich@...e.com>, Arnd Bergmann <arnd@...db.de>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kconfig: fix relational operators for bool and tristate symbols

2017-11-17 10:06 GMT+09:00 Nicolas Pitre <nicolas.pitre@...aro.org>:
> Since commit 31847b67bec0 ("kconfig: allow use of relations other than
> (in)equality") it is possible to use relational operators in Kconfig
> statements. However, those operators give unexpected results when
> applied to bool/tristate values:
>
>         (n < y) = y (correct)
>         (m < y) = y (correct)
>         (n < m) = n (wrong)
>
> This happens because relational operators process bool and tristate
> symbols as strings and m sorts before n. It makes little sense to do a
> lexicographical compare on bool and tristate values though.
>
> Documentation/kbuild/kconfig-language.txt states that expression can have
> a value of 'n', 'm' or 'y' (or 0, 1, 2 respectively for calculations).
> Let's make it so for relational comparisons with bool/tristate
> expressions as well and document them. If at least one symbol is an
> actual string then the lexicographical compare works just as before.
>
> Signed-off-by: Nicolas Pitre <nico@...aro.org>
>

Applied to linux-kbuild/fixes.  Thanks!

-- 
Best Regards
Masahiro Yamada