[PATCH v2] checkpatch: Allow to pass config directory

[Petr Vorel]

checkpatch.pl searches for .checkpatch.conf in $HOME and .scripts
(in current working directory). Allow to pass directory via
CHECKPATCH_CONFIG_DIR environment variable. This allows to directly use
project configuration file for projects which vendored checkpatch.pl
(e.g. LTP or u-boot).

While at it, document all directories in help.

Suggested-by: Joe Perches <joe@xxxxxxxxxxx>
Signed-off-by: Petr Vorel <pvorel@xxxxxxx>
---
NOTE: if you don't like the way how directories are printed in help
(user's home directory path instead of $HOME) I can change it.

$ ./scripts/checkpatch.pl -h
...
When FILE is - read standard input.

CONFIGURATION FILE

Script searches for a configuration file .checkpatch.conf in path:
$CHECKPATCH_CONFIG_DIR:.:/home/foo:.scripts

Link to v1:
https://lore.kernel.org/lkml/20260202144221.76765-1-pvorel@xxxxxxx/
https://lore.kernel.org/lkml/20260202144221.76765-2-pvorel@xxxxxxx/

Changes v1->v2:
* Use environment variable instead of --conf-dir option (Joe Perches)
NOTE: I'd slightly prefer using --conf-dir (more convenient for user).
* squash documentation into this commit

Kind regards,
Petr

 scripts/checkpatch.pl | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index bec7930cdd66..e47fec115ee7 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -57,6 +57,8 @@ my %ignore_type = ();
 my @ignore = ();
 my $help = 0;
 my $configuration_file = ".checkpatch.conf";
+my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
+my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
 my $max_line_length = 100;
 my $ignore_perl_version = 0;
 my $minimum_perl_version = 5.10.0;
@@ -146,6 +148,10 @@ Options:
   -h, --help, --version      display this help and exit
 
 When FILE is - read standard input.
+
+CONFIGURATION FILE
+Script searches for a configuration file $configuration_file in path:
+\$$env_config_dir:$def_configuration_dirs
 EOM
 
 	exit($exitcode);
@@ -1531,8 +1537,10 @@ sub which {
 
 sub which_conf {
 	my ($conf) = @_;
+	my $paths = $ENV{$env_config_dir} . ':' if exists($ENV{$env_config_dir});
+	$paths .= $def_configuration_dirs;
 
-	foreach my $path (split(/:/, ".:$ENV{HOME}:.scripts")) {
+	foreach my $path (split(/:/, $paths)) {
 		if (-e "$path/$conf") {
 			return "$path/$conf";
 		}
-- 
2.51.0