Re: [PATCH v2] checkpatch: add command-line option for TAB size

Joe Perches
2019-05-08T17:56:13Z

On Wed, 2019-05-08 at 19:43 +0200, Antonio Borneo wrote:
> The size of 8 characters used for both TAB and indentation is
> embedded as magic value allover the checkpatch script, and this
> makes the script less readable.

I doubt this bit of the commit message is proper.

Tabs _are_ 8 in the linux-kernel sources and checkpatch
was written for the linux-kernel.

Using a variable _could_ reasonably be described as an
improvement, but readability wasn't and isn't really an
issue here.

Other than that, the patch seems fine.

thanks, Joe

> Replace the magic value 8 with a variable.
> From the context of the code it's clear if it is used for
> indentation or tabulation, so no need to use two separate
> variables.
>
> Add a command-line option "--tab-size" to let the user select a
> TAB size value other than 8.
> This makes easy to reuse this script by other projects with
> different requirements in their coding style (e.g. OpenOCD [1]
> requires TAB size of 4 characters [2]).
>
> [1] http://openocd.org/
> [2] http://openocd.org/doc/doxygen/html/stylec.html#styleformat
>
> Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
> Signed-off-by: Erik Ahlén <erik.ahlen@avalonenterprise.com>
> Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
> ---
> V1 -> V2
> add the command line option
>
> scripts/checkpatch.pl | 23 +++++++++++++----------
> 1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 916a3fbd4d47..90f641bf1895 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -62,6 +62,7 @@ my $conststructsfile = "$D/const_structs.checkpatch";
> my $typedefsfile = "";
> my $color = "auto";
> my $allow_c99_comments = 1; # Can be overridden by --ignore C99_COMMENT_TOLERANCE
> +my $tabsize = 8;
>
> sub help {
> my ($exitcode) = @_;
> @@ -96,6 +97,7 @@ Options:
> --show-types show the specific message type in the output
> --max-line-length=n set the maximum line length, if exceeded, warn
> --min-conf-desc-length=n set the min description length, if shorter, warn
> + --tab-size=n set the number of spaces for tab (default 8)
> --root=PATH PATH to the kernel tree root
> --no-summary suppress the per-file summary
> --mailback only produce a report in case of warnings/errors
> @@ -213,6 +215,7 @@ GetOptions(
> 'list-types!' => \$list_types,
> 'max-line-length=i' => \$max_line_length,
> 'min-conf-desc-length=i' => \$min_conf_desc_length,
> + 'tab-size=i' => \$tabsize,
> 'root=s' => \$root,
> 'summary!' => \$summary,
> 'mailback!' => \$mailback,
> @@ -1211,7 +1214,7 @@ sub expand_tabs {
> if ($c eq "\t") {
> $res .= ' ';
> $n++;
> - for (; ($n % 8) != 0; $n++) {
> + for (; ($n % $tabsize) != 0; $n++) {
> $res .= ' ';
> }
> next;
> @@ -2224,7 +2227,7 @@ sub string_find_replace {
> sub tabify {
> my ($leading) = @_;
>
> - my $source_indent = 8;
> + my $source_indent = $tabsize;
> my $max_spaces_before_tab = $source_indent - 1;
> my $spaces_to_tab = " " x $source_indent;
>
> @@ -3153,7 +3156,7 @@ sub process {
> next if ($realfile !~ /\.(h|c|pl|dtsi|dts)$/);
>
> # at the beginning of a line any tabs must come first and anything
> -# more than 8 must use tabs.
> +# more than $tabsize must use tabs.
> if ($rawline =~ /^\+\s* \t\s*\S/ ||
> $rawline =~ /^\+\s* \s*/) {
> my $herevet = "$here\n" . cat_vet($rawline) . "\n";
> @@ -3172,7 +3175,7 @@ sub process {
> "please, no space before tabs\n" . $herevet) &&
> $fix) {
> while ($fixed[$fixlinenr] =~
> - s/(^\+.*) {8,8}\t/$1\t\t/) {}
> + s/(^\+.*) {$tabsize,$tabsize}\t/$1\t\t/) {}
> while ($fixed[$fixlinenr] =~
> s/(^\+.*) +\t/$1\t/) {}
> }
> @@ -3194,11 +3197,11 @@ sub process {
> if ($perl_version_ok &&
> $sline =~ /^\+\t+( +)(?:$c90_Keywords\b|\{\s*$|\}\s*(?:else\b|while\b|\s*$)|$Declare\s*$Ident\s*[;=])/) {
> my $indent = length($1);
> - if ($indent % 8) {
> + if ($indent % $tabsize) {
> if (WARN("TABSTOP",
> "Statements should start on a tabstop\n" . $herecurr) &&
> $fix) {
> - $fixed[$fixlinenr] =~ s@(^\+\t+) +@$1 . "\t" x ($indent/8)@e;
> + $fixed[$fixlinenr] =~ s@(^\+\t+) +@$1 . "\t" x ($indent/$tabsize)@e;
> }
> }
> }
> @@ -3216,8 +3219,8 @@ sub process {
> my $newindent = $2;
>
> my $goodtabindent = $oldindent .
> - "\t" x ($pos / 8) .
> - " " x ($pos % 8);
> + "\t" x ($pos / $tabsize) .
> + " " x ($pos % $tabsize);
> my $goodspaceindent = $oldindent . " " x $pos;
>
> if ($newindent ne $goodtabindent &&
> @@ -3688,11 +3691,11 @@ sub process {
> #print "line<$line> prevline<$prevline> indent<$indent> sindent<$sindent> check<$check> continuation<$continuation> s<$s> cond_lines<$cond_lines> stat_real<$stat_real> stat<$stat>\n";
>
> if ($check && $s ne '' &&
> - (($sindent % 8) != 0 ||
> + (($sindent % $tabsize) != 0 ||
> ($sindent < $indent) ||
> ($sindent == $indent &&
> ($s !~ /^\s*(?:\}|\{|else\b)/)) ||
> - ($sindent > $indent + 8))) {
> + ($sindent > $indent + $tabsize))) {
> WARN("SUSPECT_CODE_INDENT",
> "suspect code indent for conditional statements ($indent, $sindent)\n" . $herecurr . "$stat_real\n");
> }