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

[Joe Perches]

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

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";
 		}