[U-Boot] [PATCH 11/21] tools: moveconfig: add --undef option to move CONFIGs with default y

[Joe Hershberger]

On Thu, May 19, 2016 at 1:51 AM, Masahiro Yamada
<yamada.masahiro at socionext.com> wrote:
> Since 96464badc794 ("moveconfig: Always run savedefconfig on the
> moved config"), this tool can not correctly move bool configs with
> the default value y.
>
> The reason is like follows:
>
> We are supposed to add the config entries in Kconfig for the options
> we are moving before running this tool.  Otherwise, the moved options
> would all disappear during the "make savedefconfig" stage.
>
> Let's say we want to move CONFIG_FOO to Kconfig, making it an option
> with "default y".  The first thing we need to do is to create an entry
> like follows:
>
>   config FOO
>           bool "foo"
>           default y
>
> So, CONFIG_FOO=y will be set in the .config for every defconfig.
>
> Commit 7740f653e6b3 ("moveconfig: Ignore duplicate configs when
> moving") introduced KCONFIG_IGNORE_DUPLICATES to fix the false
> negative (= boards that should be converted to "=y" are misconverted
> to "not set") problem.  With that commit, the CONFIGs in the .config
> are now duplicated to include/autoconf.mk unless they are defined to
> a different value or #undef'ed in the board header.  It causes false
> positive problem this time; boards without #define/#undef CONFIG_FOO
> in their header should be converted to "not set", but misconverted
> to "=y" actually.
>
> This commit intends to handle such cases correctly.  Anyway, we need
> to create a Kconfig entry beforehand to persevere savedefconfig.
> But, we do not want to propagate CONFIGs coming from "default y"
> to the include/autoconf.mk.  To achieve it, the new option --undef
> is here!
>
> We can move bool option with default y in this way:
>  1. create an entry in Kconfig
>  2. run "tools/moveconfig.py --undef=CONFIG_FOO CONFIG_FOO"

This seems tedious to use. The way I solved this didn't require any
extra specification of what was expected to happen.

http://lists.denx.de/pipermail/u-boot/2015-June/215724.html

> This option can appear multiple times in the command line, so that
> we can move multiple options at a time.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>