Subject: Re: [PATCH 1/1] checkpatch: remove false warning for commit reference
To: Joe Perches <joe@perches.com>, Andy Whitcroft <apw@canonical.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <1465608362-4677-1-git-send-email-xypron.glpk@gmx.de>
 <1477208091-4887-1-git-send-email-xypron.glpk@gmx.de>
 <1477255021.3561.9.camel@perches.com>
Cc: linux-kernel@vger.kernel.org
From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Message-ID: <ae7cd959-d5b5-d76f-1926-16bcecbaa916@gmx.de>
Date: Mon, 24 Oct 2016 19:22:33 +0200
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On 10/23/2016 10:37 PM, Joe Perches wrote:
> 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@gmx.de>
>> ---
>>  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) &&
For $id = 0 or $id = "" this would make a difference.
Surely I can update the patch like this to make the test more readable.

> 			   ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens)) {
> 
> and not wrap the tests.

Putting defined($id) on a line of its own is fine.

Not wrapping the tests will produce a line of over 80 characters and
give a warning in scripts/checkpatch.pl.

The script should respect the standards it imposes on others.

> 
> 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"));
Why not simply
return (undef, undef) if ((which("git") eq "") || !(-e ".git"));

Should we provide a warning: "git not found"?
>  
>  	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);

This will change the program logic for
if ($lines[0] =~ /^error: short SHA1 $commit is ambiguous\./)

>  }
>  
>  $chk_signoff = 0 if ($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)) {
This line is over 80 characters.
Which is not accepatble according to checkpatch.pl.

>  				ERROR("GIT_COMMIT_ID",
>  				      "Please use git commit description style 'commit <12+ chars of sha1> (\"\")' - ie: '${init_char}ommit $id (\"$description\")'\n" . $herecurr);
>  			}
> 
> 
>