linux-kernel - Re: [PATCH] kconfig: fix new choices being skipped upon config update

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Message-ID: <20120126092603.GQ6305@pengutronix.de>
Date:	Thu, 26 Jan 2012 10:26:03 +0100
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Arnaud Lacombe <lacombar@...il.com>
Cc:	linux-kbuild@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	Michal Marek <mmarek@...e.cz>
Subject: Re: [PATCH] kconfig: fix new choices being skipped upon config update

On Mon, Jan 23, 2012 at 05:29:05PM -0500, Arnaud Lacombe wrote:
> Running `oldconfig' after any of the following configuration change:
> 
> either trivial addition, such as:
> 
> config A
> 	bool "A"
> 
> choice
> 	prompt "Choice ?"
> 	depends on A
> 
> 	config CHOICE_B
> 		bool "Choice B"
> 
> 	config CHOICE_C
> 		bool "Choice C"
> endchoice
> 
> or more tricky change:
> 
> OLD KCONFIG                      |  NEW KCONFIG
>                                  |
>                                  |  config A
>                                  |          bool "A"
>                                  |
> choice                           |  choice
>         prompt "Choice ?"        |          prompt "Choice ?"
>                                  |
>         config CHOICE_C          |          config CHOICE_C
>                 bool "Choice C"  |                  bool "Choice C"
>                                  |
>         config CHOICE_D          |          config CHOICE_D
>                 bool "Choice D"  |                  bool "Choice D"
> endchoice                        |
>                                  |          config CHOICE_E
>                                  |                  bool "Choice E"
>                                  |                  depends on A
>                                  |  endchoice
> 
> will not cause the choice to be considered as NEW, and thus not be asked. The
> cause of this behavior is that choice's novelty are computed statically right
> after the saved configuration has been read. At this point, the new dependency's
> value is still unknown and asserted to be `no'. Moreover, no update to this
> decision is made afterward.
> 
> Correct this by dynamically evaluating a choice's novelty, and removing the
> static evaluation.
> 
> Cc: linux-kbuild@...r.kernel.org
> Cc: LKML <linux-kernel@...r.kernel.org>,
> Cc: Michal Marek <mmarek@...e.cz>
> Cc: Uwe Kleine-Konig <u.kleine-koenig@...gutronix.de>
> Reported-by: Uwe Kleine-Konig <u.kleine-koenig@...gutronix.de>
Tested-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>

(Please note the umlaut o in my name. If you have problems with that,
please at least write Kleine-Koenig.)

> Signed-off-by: Arnaud Lacombe <lacombar@...il.com>

Best regards and thanks
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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