linux/scripts/kconfig
Masahiro Yamada fde192511b kconfig: remove tristate choice support
I previously submitted a fix for a bug in the choice feature [1], where
I mentioned, "Another (much cleaner) approach would be to remove the
tristate choice support entirely".

There are more issues in the tristate choice feature. For example, you
can observe a couple of bugs in the following test code.

[Test Code]

    config MODULES
            def_bool y
            modules

    choice
            prompt "tristate choice"
            default A

    config A
            tristate "A"

    config B
            tristate "B"

    endchoice

Bug 1: the 'default' property is not correctly processed

'make alldefconfig' produces:

    CONFIG_MODULES=y
    # CONFIG_A is not set
    # CONFIG_B is not set

However, the correct output should be:

    CONFIG_MODULES=y
    CONFIG_A=y
    # CONFIG_B is not set

The unit test file, scripts/kconfig/tests/choice/alldef_expected_config,
is wrong as well.

Bug 2: choice members never get 'y' with randconfig

For the test code above, the following combinations are possible:

               A    B
        (1)    y    n
        (2)    n    y
        (3)    m    m
        (4)    m    n
        (5)    n    m
        (6)    n    n

'make randconfig' never produces (1) or (2).

These bugs are fixable, but a more critical problem is the lack of a
sensible syntax to specify the default for the tristate choice.
The default for the choice must be one of the choice members, which
cannot specify any of the patterns (3) through (6) above.

In addition, I have never seen it being used in a useful way.

The following commits removed unnecessary use of tristate choices:

 - df8df5e4bc ("usb: get rid of 'choice' for legacy gadget drivers")
 - bfb57ef054 ("rapidio: remove choice for enumeration")

This commit removes the tristate choice support entirely, which allows
me to delete a lot of code, making further refactoring easier.

Note:
This includes the revert of commit fa64e5f6a3 ("kconfig/symbol.c:
handle choice_values that depend on 'm' symbols"). It was suspicious
because it did not address the root cause but introduced inconsistency
in visibility between choice members and other symbols.

[1]: https://lore.kernel.org/linux-kbuild/20240427104231.2728905-1-masahiroy@kernel.org/T/#m0a1bb6992581462ceca861b409bb33cb8fd7dbae

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-07-16 01:08:36 +09:00
..
lxdialog kconfig: lxdialog: remove initialization with A_NORMAL 2024-05-14 23:36:19 +09:00
tests kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
.gitignore kconfig: Update all declared targets 2023-01-13 16:29:52 +09:00
array_size.h kconfig: move ARRAY_SIZE to a header 2024-02-19 18:20:41 +09:00
conf.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
confdata.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
expr.c kconfig: remove wrong expr_trans_bool() 2024-06-06 20:09:10 +09:00
expr.h kconfig: remove wrong expr_trans_bool() 2024-06-06 20:09:10 +09:00
gconf-cfg.sh kconfig: refactor Makefile to reduce process forks 2022-12-13 22:29:10 +09:00
gconf.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
gconf.glade scripts/kconfig/gconf.glade Update broken web addresses. 2010-09-17 16:54:42 +02:00
hashtable.h kconfig: add macros useful for hashtable 2024-02-19 18:20:41 +09:00
images.c kconfig: constify XPM data 2020-08-14 13:30:03 +09:00
images.h kconfig: constify XPM data 2020-08-14 13:30:03 +09:00
internal.h kconfig: use generic macros to implement symbol hashtable 2024-02-20 20:47:45 +09:00
lexer.l kconfig: remove 'optional' property support 2024-05-02 19:48:26 +09:00
list_types.h kconfig: import more list macros and inline functions 2024-02-19 18:20:41 +09:00
list.h kconfig: import more list macros and inline functions 2024-02-19 18:20:41 +09:00
lkc_proto.h kconfig: pass new conf_changed value to the callback 2024-07-16 01:08:36 +09:00
lkc.h kconfig: remove 'optional' property support 2024-05-02 19:48:26 +09:00
Makefile kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
mconf-cfg.sh kconfig: refactor Makefile to reduce process forks 2022-12-13 22:29:10 +09:00
mconf.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
menu.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
merge_config.sh scripts: merge_config: Fix typo in variable name. 2023-03-23 15:27:40 +09:00
mnconf-common.c kconfig: factor out common code shared by mconf and nconf 2023-12-10 15:34:37 +09:00
mnconf-common.h kconfig: factor out common code shared by mconf and nconf 2023-12-10 15:34:37 +09:00
nconf-cfg.sh kconfig: refactor Makefile to reduce process forks 2022-12-13 22:29:10 +09:00
nconf.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
nconf.gui.c kconfig: nconf: Add search jump feature 2023-08-13 21:29:41 +09:00
nconf.h kconfig: nconf: Add search jump feature 2023-08-13 21:29:41 +09:00
parser.y kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
preprocess.c kconfig: move ARRAY_SIZE to a header 2024-02-19 18:20:41 +09:00
preprocess.h kconfig: split preprocessor prototypes into preprocess.h 2024-02-19 18:20:40 +09:00
qconf-cfg.sh kconfig: port qconf to work with Qt6 in addition to Qt5 2023-08-16 12:06:29 +09:00
qconf.cc kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
qconf.h kconfig: pass new conf_changed value to the callback 2024-07-16 01:08:36 +09:00
streamline_config.pl streamline_config.pl: handle also ${CONFIG_FOO} 2023-06-08 11:11:32 +09:00
symbol.c kconfig: remove tristate choice support 2024-07-16 01:08:36 +09:00
util.c kconfig: convert linked list of files to hash table 2024-02-20 20:44:48 +09:00