[PATCH] checkpatch: warn if changed lines exceeds a maximum size

From: Nicholas Brown
Date: Tue Jan 30 2018 - 14:02:06 EST


Changed lines is the total of inserted and deleted lines.
By default there is no limit, --max-changed-lines may be used to set a
value. Some users may wish to encourage that patches are split into
smaller parts using this.
See Documentation/process/submitting-patches.rst#split-changes

Signed-off-by: Nicholas Brown <nick.brown@xxxxxxx>
---
scripts/checkpatch.pl | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 31031f10fe56..2847109b4def 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -49,6 +49,7 @@ my @ignore = ();
my $help = 0;
my $configuration_file = ".checkpatch.conf";
my $max_line_length = 80;
+my $max_changed_lines; # undef = no max
my $ignore_perl_version = 0;
my $minimum_perl_version = 5.10.0;
my $min_conf_desc_length = 4;
@@ -92,6 +93,8 @@ Options:
--ignore TYPE(,TYPE2...) ignore various comma separated message types
--show-types show the specific message type in the output
--max-line-length=n set the maximum line length, if exceeded, warn
+ --max-changed-lines=n set the maximum number of changed lines allowed,
+ if exceeded, warn. (insertions + deletions)
--min-conf-desc-length=n set the min description length, if shorter, warn
--root=PATH PATH to the kernel tree root
--no-summary suppress the per-file summary
@@ -209,6 +212,7 @@ GetOptions(
'show-types!' => \$show_types,
'list-types!' => \$list_types,
'max-line-length=i' => \$max_line_length,
+ 'max-changed-lines=i' => \$max_changed_lines,
'min-conf-desc-length=i' => \$min_conf_desc_length,
'root=s' => \$root,
'summary!' => \$summary,
@@ -2165,6 +2169,8 @@ sub process {
my $filename = shift;

my $linenr=0;
+ my $inserted_lines_total=0;
+ my $deleted_lines_total=0;
my $prevline="";
my $prevrawline="";
my $stashline="";
@@ -2233,6 +2239,14 @@ sub process {

push(@fixed, $rawline) if ($fix);

+ if ($rawline=~/^\+/) {
+ $inserted_lines_total++
+ }
+
+ if ($rawline=~/^-/) {
+ $deleted_lines_total++
+ }
+
if ($rawline=~/^\+\+\+\s+(\S+)/) {
$setup_docs = 0;
if ($1 =~ m@Documentation/admin-guide/kernel-parameters.rst$@) {
@@ -2306,6 +2320,11 @@ sub process {

$prefix = '';

+ if (defined $max_changed_lines &&
+ ($inserted_lines_total+$deleted_lines_total > $max_changed_lines)) {
+ WARN("MAX_CHANGED_LINES", "please split the change into smaller parts\n");
+ }
+
$realcnt = 0;
$linenr = 0;
$fixlinenr = -1;
--
2.14.1