Re: [PATCH 1/1] checkpatch: remove false warning for commit reference

[Joe Perches]

On Sun, 2016-10-23 at 09:34 +0200, Heinrich Schuchardt wrote:
> Checkpatch warns of an incorrect commit reference style
> for any hexadecimal number of 12 digits and more.
> 
> Numbers of 12 digits are not necessarily commit ids.
> 
> For an example provoking the problem see
> https://patchwork.kernel.org/patch/9170897/
> 
> Checkpatch should only warn if the number refers to an
> existing commit.

That seems sensible.

> Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx>
> ---
>  scripts/checkpatch.pl | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -848,6 +848,7 @@ sub git_commit_info {
>  #		    echo "commit $(cut -c 1-12,41-)"
>  #		done
>  	} elsif ($lines[0] =~ /^fatal: ambiguous argument '$commit': unknown revision or path not in the working tree\./) {
> +		$id = undef;

OK

>  	} else {
>  		$id = substr($lines[0], 0, 12);
>  		$desc = substr($lines[0], 41);
> @@ -2577,7 +2578,9 @@ sub process {
>  			($id, $description) = git_commit_info($orig_commit,
>  							      $id, $orig_desc);
>  
> -			if ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens) {
> +			if ($id && ($short || $long || $space || $case
> +				|| ($orig_desc ne $description)
> +				|| !$hasparens)) {

I'd prefer
			if (defined($id) &&
			   ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens)) {

and not wrap the tests.

Maybe ignore all the cases there git is not installed too.
Something like:
---
 scripts/checkpatch.pl | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a8368d1c4348..a46b6ebe067b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -829,13 +829,16 @@ sub seed_camelcase_includes {
 sub git_commit_info {
 	my ($commit, $id, $desc) = @_;
 
-	return ($id, $desc) if ((which("git") eq "") || !(-e ".git"));
+	my $git_id = undef;
+	my $git_desc = undef;
+
+	return ($git_id, $git_desc) if ((which("git") eq "") || !(-e ".git"));
 
 	my $output = `git log --no-color --format='%H %s' -1 $commit 2>&1`;
 	$output =~ s/^\s*//gm;
 	my @lines = split("\n", $output);
 
-	return ($id, $desc) if ($#lines < 0);
+	return ($git_id, $git_desc) if ($#lines < 0);
 
 	if ($lines[0] =~ /^error: short SHA1 $commit is ambiguous\./) {
 # Maybe one day convert this block of bash into something that returns
@@ -849,11 +852,11 @@ sub git_commit_info {
 #		done
 	} elsif ($lines[0] =~ /^fatal: ambiguous argument '$commit': unknown revision or path not in the working tree\./) {
 	} else {
-		$id = substr($lines[0], 0, 12);
-		$desc = substr($lines[0], 41);
+		$git_id = substr($lines[0], 0, 12);
+		$git_desc = substr($lines[0], 41);
 	}
 
-	return ($id, $desc);
+	return ($git_id, $git_desc);
 }
 
 $chk_signoff = 0 if ($file);
@@ -2577,7 +2580,8 @@ sub process {
 			($id, $description) = git_commit_info($orig_commit,
 							      $id, $orig_desc);
 
-			if ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens) {
+			if (defined($id) &&
+			    ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens)) {
 				ERROR("GIT_COMMIT_ID",
 				      "Please use git commit description style 'commit <12+ chars of sha1> (\"\")' - ie: '${init_char}ommit $id (\"$description\")'\n" . $herecurr);
 			}