Re: [PATCH 1/1] Kconfig: Added compare capabilities for mconf

[Nicolas Schier <nsc@kernel.org>]

Hi Franco,

thanks for your contribution.  Some notes below:

On Thu, Oct 30, 2025 at 03:13:42PM +0100, Franco Martelli wrote:
> This patch allows to compare the tristate value of two .config files
> inline, symbol by symbol, in mconf (make menuconfig) only. It can be
> really useful when customizing the .config file.
> 
> When a new stable release of a distribution is available, in the Linux
> kernel many things has changed, this patch comes in help in this
> situations, it allows to easily compare the customized .config file
> built for the previous version of the distribution, with the one
> provided by the new software distribution, used as reference.
> Generally it can be helpful when the differences between .config files
> are huge, because you can navigate across them in the menu window.
> 
> The patch has a limitation, it only show the tristate value (Y/N/M) not
> differences for symbol with a value (string), but it also marks with a
> "#" the symbol missing in the loaded .config, meaning therefore the
> symbol as a new feature.

I must confess, that I am not convinced yet, that this will be helpful
for general purposes.  Yes, large changes in .config files are not easy
to parse, but I do not see how your solution is easier to handle than
the use of scripts/diffconfig, other than not showing removed config
options.

> 
> o I've also added support for the more canonical <F1> key to show inline
>   help window, in addition to <?> and <h> keys.

Please split-off logical these independent changes into separate
patches (Add support for 'F1' hot-key).

Using simple letters (here 'h') as hot-keys is not a good idea as those
are already used for jumping through the currently shown menu item
(cp. highlighted letters in menu config screens).

> o By pressing the <F2> or <D> key you will get a view with all the
>   symbol differences listed.
> 
> o By pressing the <F4> or <F> key you'll save to a file the differences.

While the list might be helpful for comparing two config files, a large
list within an ncurses window does not look like a good thing to me.

When I save the list to a file (F4), I'd rather choose the output of
diffconfig for evaluation -- as it is more complete and has a layout
that looks more straight-forward and clear to me.

> o Added help text that it describes the new features.
> 
> This software is under GPL-2.0 license.

Please note that the whole Linux kernel source and its build system is
GPL-2.0 per se, cp. COPYING and the SPDX header line in each file.

> 
> Changelog:
> ----------
> 
> scripts/kconfig/confdata.c:
> ---------------------------
> 
> Silenced a warning emitted when parsing the .config file to compare.
[...]

Please put any patch changelog below the triple-dash line ('---').


I have not looked at the code, yet, as I have doubts regarding the
usefulness (see above).

Iff nobody mentions strong interest in these changes, please re-evaluate
if it makes sense for you to invest into a v5.


Kind regards,
Nicolas