Re: [PATCH v2 3/5] kconfig: check for hex and int mismatches

[Nicolas Schier]

On Tue, Sep 15, 2026 at 10:15:06PM +0100, Julian Braha wrote:
> Using a numeric option of one type (e.g. 'int') to determine the value of
> a different numeric type (e.g. 'hex') currently fails silently in various
> ways if attempted, because the underlying string representation is naively
> reused.
> 
> Example 1:
> 
>   config I
>     int
>     default -1
> 
>   config HEX_DEFAULT_INT
>     hex
>     default I
> 
> Here, HEX_DEFAULT_INT actually gets set to '0x-1', which is of course not
> a valid hex value.
> 
> Example 2:
> 
>   config H
>     hex
>     default A
> 
>   config INT_DEFAULT_HEX
>     int
>     default H
> 
> Here, INT_DEFAULT_HEX actually gets set to 'A', without even converting
> into the base-10 equivalent of 10. This value, 'A', is otherwise a
> rejected int value if entered in the frontend, or read in from an existing
> .config file.
> 
> These int-hex mismatches currently do not appear anywhere in the tree, so
> it is already safe to make these error out.
> 
> Assisted-by: LLM
> Signed-off-by: Julian Braha <julianbraha@xxxxxxxxx>
> ---
>  scripts/kconfig/menu.c                        |  2 +-
>  .../kconfig/tests/err_num_mismatch/Kconfig    | 38 +++++++++++++++++++
>  .../tests/err_num_mismatch/__init__.py        |  9 +++++
>  .../tests/err_num_mismatch/expected_stderr    |  4 ++
>  4 files changed, 52 insertions(+), 1 deletion(-)
>  create mode 100644 scripts/kconfig/tests/err_num_mismatch/Kconfig
>  create mode 100644 scripts/kconfig/tests/err_num_mismatch/__init__.py
>  create mode 100644 scripts/kconfig/tests/err_num_mismatch/expected_stderr
> 

Thanks, error-out is really a good thing for now.  Actually, I am one of 
those who'd expect that Kconfig auto-converts hex ←→ int; so, thanks for 
enforcing clarity.

Reviewed-by: Nicolas Schier <n.schier@xxxxxxxxx>

-- 
Nicolas