Subject: Re: linux-next: Fixes tag needs some work in the tip tree

From: Joe Perches <[email-masked]>
Date: Thu, 17 Jan 2019 17:19:37 -0800

On Fri, 2019-01-18 at 11:32 +1100, Stephen Rothwell wrote:
> Hi Thomas,
> 
> On Fri, 18 Jan 2019 00:45:44 +0100 (CET) Thomas Gleixner <[email-masked]> wrote:
> > On Fri, 18 Jan 2019, Stephen Rothwell wrote:
> > > Commit
> > > 
> > >   a31e184e4f69 ("x86/pkeys: Properly copy pkey state at fork()")
> > > 
> > > Fixes tag
> > > 
> > >   Fixes: e8c24d3a23a ("x86/pkeys: Allocation/free syscalls")
> > > 
> > > has these problems:
> > > 
> > >   - SHA1 should be at least 12 digits long  
> > 
> > Sigh. I'll add that to my sanity checks, but this one has to be as is as
> > it's in the middle of a series of fixes pending for linus tree.
> 
> That's OK, more of a reminder ... the abbreviated SHA1 is unique now,
> but may not be in the future - of course 12 digits does not guarantee
> that either.  I am told we already have some clashes using 11 digits :-(

Ævar Arnfjörð Bjarmason sent a [atch to
	Documentation/process/submitting-patches.rst
for that .gitconfig default length problem last month.

https://lore.kernel.org/patchwork/patch/1026639/

Perhaps something will come of that one day.

It does seem that of the 30K or so commits with "Fixes:" that
the style has standardized on the typical form below where
12 ("") is a 12 char SHA1 and ("") is the commit description

  21911 Fixes: 12 ("")
   1151 Fixes: 13 ("")
   1053 Fixes: 12 (')
    541 Fixes: 16 ("")
    325 Fixes: 10 ("")
    323 Fixes: 40
    274 Fixes:
    272 Fixes: 12 ""
    256 Fixes: 11 ("")
    217 Fixes: 14 ("")
    188 Fixes: commit 12 ("")
    181 Fixes: 8 ("")
    178 Fixes: 7 ("")
    163 Fixes: 9 ("")
     94 Fixes: 15 ("")
     51 Fixes: 12("")
     48 Fixes: 13 (')
     38 Fixes: 12
     35 Fixes: 12(')
     34 Fixes: 40 ("")
     30 Fixes: 12 (""
     28 Fixes: 17 ("")
     24 Fixes: Commit 12 ("")

So for checkpatch, maybe something like the below
would help standardize the Fixes line:
---
 scripts/checkpatch.pl | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 155fa9305166..a1aa3787d0b0 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2730,10 +2730,11 @@ sub process {
 		    $line !~ /^This reverts commit [0-9a-f]{7,40}/ &&
 		    ($line =~ /\bcommit\s+[0-9a-f]{5,}\b/i ||
 		     ($line =~ /(?:\s|^)[0-9a-f]{12,40}(?:[\s"'\(\[]|$)/i &&
-		      $line !~ /[\<\[][0-9a-f]{12,40}[\>\]]/i &&
-		      $line !~ /\bfixes:\s*[0-9a-f]{12,40}/i))) {
+		      $line !~ /[\<\[][0-9a-f]{12,40}[\>\]]/i))) {
 			my $init_char = "c";
 			my $orig_commit = "";
+			my $prefix = "commit";
+			my $prefix_case = "[Cc]ommit";
 			my $short = 1;
 			my $long = 0;
 			my $case = 1;
@@ -2744,18 +2745,24 @@ sub process {
 			my $orig_desc = "commit description";
 			my $description = "";
 
-			if ($line =~ /\b(c)ommit\s+([0-9a-f]{5,})\b/i) {
+			if ($line =~ /\b(f)ixes:\s+([0-9a-f]{5,})\b/i) {
+				$init_char = $1;
+				$orig_commit = lc($2);
+				$prefix = "Fixes:";
+				$prefix_case = "Fixes:";
+				$init_char = "F";
+			} elsif ($line =~ /\b(c)ommit\s+([0-9a-f]{5,})\b/i) {
 				$init_char = $1;
 				$orig_commit = lc($2);
 			} elsif ($line =~ /\b([0-9a-f]{12,40})\b/i) {
 				$orig_commit = lc($1);
 			}
 
-			$short = 0 if ($line =~ /\bcommit\s+[0-9a-f]{12,40}/i);
-			$long = 1 if ($line =~ /\bcommit\s+[0-9a-f]{41,}/i);
-			$space = 0 if ($line =~ /\bcommit [0-9a-f]/i);
-			$case = 0 if ($line =~ /\b[Cc]ommit\s+[0-9a-f]{5,40}[^A-F]/);
-			if ($line =~ /\bcommit\s+[0-9a-f]{5,}\s+\("([^"]+)"\)/i) {
+			$short = 0 if ($line =~ /\b$prefix\s+[0-9a-f]{12,40}/i);
+			$long = 1 if ($line =~ /\b$prefix\s+[0-9a-f]{41,}/i);
+			$space = 0 if ($line =~ /\b$prefix [0-9a-f]/i);
+			$case = 0 if ($line =~ /\b$prefix_case\s+[0-9a-f]{5,40}[^A-F]/);
+			if ($line =~ /\b$prefix\s+[0-9a-f]{5,}\s+\("([^"]+)"\)/i) {
 				$orig_desc = $1;
 				$hasparens = 1;
 			} elsif ($line =~ /\bcommit\s+[0-9a-f]{5,}\s*$/i &&
@@ -2763,10 +2770,10 @@ sub process {
 				 $rawlines[$linenr] =~ /^\s*\("([^"]+)"\)/) {
 				$orig_desc = $1;
 				$hasparens = 1;
-			} elsif ($line =~ /\bcommit\s+[0-9a-f]{5,}\s+\("[^"]+$/i &&
+			} elsif ($line =~ /\b$prefix\s+[0-9a-f]{5,}\s+\("[^"]+$/i &&
 				 defined $rawlines[$linenr] &&
 				 $rawlines[$linenr] =~ /^\s*[^"]+"\)/) {
-				$line =~ /\bcommit\s+[0-9a-f]{5,}\s+\("([^"]+)$/i;
+				$line =~ /\b$prefix\s+[0-9a-f]{5,}\s+\("([^"]+)$/i;
 				$orig_desc = $1;
 				$rawlines[$linenr] =~ /^\s*([^"]+)"\)/;
 				$orig_desc .= " " . $1;
@@ -2779,7 +2786,7 @@ sub process {
 			if (defined($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> (\"<title line>\")' - ie: '${init_char}ommit $id (\"$description\")'\n" . $herecurr);
+				      "Please use git commit description style '$prefix <12+ chars of sha1> (\"<title line>\")' - ie: '${init_char}" . substr($prefix, 1) . " $id (\"$description\")'\n" . $herecurr);
 			}
 		}