Re: [PATCH 2/2] checkpatch: Add --conf-dir option

[Petr Vorel <pvorel@suse.cz>]

> On Mon, 2026-02-23 at 16:53 +0100, Petr Vorel wrote:
> > On Mon, 2026-02-02 at 15:42 +0100, Petr Vorel wrote:
> > > > This allows to directly use project configuration file for projects
> > > > which vendored checkpatch.pl (e.g. LTP or u-boot).
> []
> > > Extend 'sub which_conf {' and the perhaps the code that uses it
> > > if you really need this capability.

> > Thanks for a hint. If there is a chance it will be accepted I'll have look on
> > it. We would certainly appreciated not having to carry yet another checkpatch.pl
> > patch in LTP.
> []
> > > Though I think it's not all that useful.
> []
> > We use LTP in makefile targets run from various subdirectories. For that we
> > define our checkpatch.pl options (--ignore list and others) in certain Makefile.
> > Then we have b4 configuration, where we also use checkpatch.pl options.

> > Mixing cd to rootdir and passing path to the sources is of course doable
> > (to reach config file in .scripts in project root directory) but quite ugly.

> > Also, allowing to pass a configuration file (quite common feature for any
> > software) would allow to run checkpatch.pl with different configs for different
> > projects.

> Right now the HOME environment variable is used in which_conf.
Yes (and that's not enough for the case I described).

> Perhaps prepend a CHECKPATCH_CONFIG environment where the right
> <somedir>.checkpatch.conf would be found?

Sure, if you prefer not processing @ARGV twice (and modifying it), using
environment variable works as well. The reason I touched @ARGV was to be
slightly more convenient for user with a bit more complicated code. But when
variable is properly documented, there is practically no difference (if I ignore
the fact that in the future somebody writes bash-completion support, which will
ignore environment variables).

Anyway, thanks for being open to the idea. I'll send a patch based on the code
you proposed.

Kind regards,
Petr

> Maybe something like the below and executed with something like
> $ CHECKPATCH_CONFIG=<dir> <path_to>checkpatch.pl etc...
> ---
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index e56374662ff7..355542d7d5a9 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -1532,7 +1532,11 @@ sub which {
>  sub which_conf {
>         my ($conf) = @_;

> -	foreach my $path (split(/:/, ".:$ENV{HOME}:.scripts")) {
> +	my $env_config_path = 'CHECKPATCH_CONFIG';
> +	my $paths = $ENV{$env_config_path} . ':' if exists($ENV{$env_config_path});
> +	$paths .= ".:$ENV{'HOME'}:.scripts";
> +
> +	foreach my $path (split(/:/, $paths)) {
>  		if (-e "$path/$conf") {
>  			return "$path/$conf";
>  		}