checkpatch: add new warnings to author signoff checks.

The author signed-off-by checks are currently very vague.  Cases like same
name or same address are not handled separately.

For example, running checkpatch on commit be6577af0cef ("parisc: Add
atomic64_set_release() define to avoid CPU soft lockups"), gives:

WARNING: Missing Signed-off-by: line by nominal patch author
'John David Anglin <dave.anglin@bell.net>'

The signoff line was:
"Signed-off-by: Dave Anglin <dave.anglin@bell.net>"

Clearly the author has signed off but with a slightly different version
of his name. A more appropriate warning would have been to point out
at the name mismatch instead.

Previously, the values assumed by $authorsignoff were either 0 or 1
to indicate whether a proper sign off by author is present.
Extended the checks to handle four new cases.

$authorsignoff values now denote the following:

0: Missing sign off by patch author.

1: Sign off present and identical.

2: Addresses and names match, but comments differ.
   "James Watson(JW) <james@gmail.com>", "James Watson <james@gmail.com>"

3: Addresses match, but names are different.
   "James Watson <james@gmail.com>", "James <james@gmail.com>"

4: Names match, but addresses are different.
   "James Watson <james@watson.com>", "James Watson <james@gmail.com>"

5: Names match, addresses excluding subaddress details (RFC 5233) match.
   "James Watson <james@gmail.com>", "James Watson <james+a@gmail.com>"

Also introduced a new message type FROM_SIGN_OFF_MISMATCH
for cases 2, 3, 4 and 5.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/linux-kernel-mentees/c1ca28e77e8e3bfa7aadf3efa8ed70f97a9d369c.camel@perches.com/
Link: https://lkml.kernel.org/r/20201007192029.551744-1-dwaipayanray1@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e1ddcaf..4223a9a 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1181,10 +1181,10 @@ sub parse_email {
                }
        }
 
+       $comment = trim($comment);
        $name = trim($name);
        $name =~ s/^\"|\"$//g;
-       $name =~ s/(\s*\([^\)]+\))\s*//;
-       if (defined($1)) {
+       if ($name =~ s/(\s*\([^\)]+\))\s*//) {
                $name_comment = trim($1);
        }
        $address = trim($address);
@@ -1199,10 +1199,12 @@ sub parse_email {
 }
 
 sub format_email {
-       my ($name, $address) = @_;
+       my ($name, $name_comment, $address, $comment) = @_;
 
        my $formatted_email;
 
+       $name_comment = trim($name_comment);
+       $comment = trim($comment);
        $name = trim($name);
        $name =~ s/^\"|\"$//g;
        $address = trim($address);
@@ -1215,9 +1217,9 @@ sub format_email {
        if ("$name" eq "") {
                $formatted_email = "$address";
        } else {
-               $formatted_email = "$name <$address>";
+               $formatted_email = "$name$name_comment <$address>";
        }
-
+       $formatted_email .= "$comment";
        return $formatted_email;
 }
 
@@ -1225,17 +1227,23 @@ sub reformat_email {
        my ($email) = @_;
 
        my ($email_name, $name_comment, $email_address, $comment) = parse_email($email);
-       return format_email($email_name, $email_address);
+       return format_email($email_name, $name_comment, $email_address, $comment);
 }
 
 sub same_email_addresses {
-       my ($email1, $email2) = @_;
+       my ($email1, $email2, $match_comment) = @_;
 
        my ($email1_name, $name1_comment, $email1_address, $comment1) = parse_email($email1);
        my ($email2_name, $name2_comment, $email2_address, $comment2) = parse_email($email2);
 
+       if ($match_comment != 1) {
+               return $email1_name eq $email2_name &&
+                      $email1_address eq $email2_address;
+       }
        return $email1_name eq $email2_name &&
-              $email1_address eq $email2_address;
+              $email1_address eq $email2_address &&
+              $name1_comment eq $name2_comment &&
+              $comment1 eq $comment2;
 }
 
 sub which {
@@ -2365,6 +2373,7 @@ sub process {
        my $signoff = 0;
        my $author = '';
        my $authorsignoff = 0;
+       my $author_sob = '';
        my $is_patch = 0;
        my $is_binding_patch = -1;
        my $in_header_lines = $file ? 0 : 1;
@@ -2692,9 +2701,37 @@ sub process {
                if ($line =~ /^\s*signed-off-by:\s*(.*)/i) {
                        $signoff++;
                        $in_commit_log = 0;
-                       if ($author ne '') {
-                               if (same_email_addresses($1, $author)) {
+                       if ($author ne ''  && $authorsignoff != 1) {
+                               if (same_email_addresses($1, $author, 1)) {
                                        $authorsignoff = 1;
+                               } else {
+                                       my $ctx = $1;
+                                       my ($email_name, $email_comment, $email_address, $comment1) = parse_email($ctx);
+                                       my ($author_name, $author_comment, $author_address, $comment2) = parse_email($author);
+
+                                       if ($email_address eq $author_address && $email_name eq $author_name) {
+                                               $author_sob = $ctx;
+                                               $authorsignoff = 2;
+                                       } elsif ($email_address eq $author_address) {
+                                               $author_sob = $ctx;
+                                               $authorsignoff = 3;
+                                       } elsif ($email_name eq $author_name) {
+                                               $author_sob = $ctx;
+                                               $authorsignoff = 4;
+
+                                               my $address1 = $email_address;
+                                               my $address2 = $author_address;
+
+                                               if ($address1 =~ /(\S+)\+\S+(\@.*)/) {
+                                                       $address1 = "$1$2";
+                                               }
+                                               if ($address2 =~ /(\S+)\+\S+(\@.*)/) {
+                                                       $address2 = "$1$2";
+                                               }
+                                               if ($address1 eq $address2) {
+                                                       $authorsignoff = 5;
+                                               }
+                                       }
                                }
                        }
                }
@@ -2751,7 +2788,7 @@ sub process {
                        }
 
                        my ($email_name, $name_comment, $email_address, $comment) = parse_email($email);
-                       my $suggested_email = format_email(($email_name, $email_address));
+                       my $suggested_email = format_email(($email_name, $name_comment, $email_address, $comment));
                        if ($suggested_email eq "") {
                                ERROR("BAD_SIGN_OFF",
                                      "Unrecognized email address: '$email'\n" . $herecurr);
@@ -2761,9 +2798,9 @@ sub process {
                                $dequoted =~ s/" </ </;
                                # Don't force email to have quotes
                                # Allow just an angle bracketed address
-                               if (!same_email_addresses($email, $suggested_email)) {
+                               if (!same_email_addresses($email, $suggested_email, 0)) {
                                        WARN("BAD_SIGN_OFF",
-                                            "email address '$email' might be better as '$suggested_email$comment'\n" . $herecurr);
+                                            "email address '$email' might be better as '$suggested_email'\n" . $herecurr);
                                }
                        }
 
@@ -6943,9 +6980,33 @@ sub process {
                if ($signoff == 0) {
                        ERROR("MISSING_SIGN_OFF",
                              "Missing Signed-off-by: line(s)\n");
-               } elsif (!$authorsignoff) {
-                       WARN("NO_AUTHOR_SIGN_OFF",
-                            "Missing Signed-off-by: line by nominal patch author '$author'\n");
+               } elsif ($authorsignoff != 1) {
+                       # authorsignoff values:
+                       # 0 -> missing sign off
+                       # 1 -> sign off identical
+                       # 2 -> names and addresses match, comments mismatch
+                       # 3 -> addresses match, names different
+                       # 4 -> names match, addresses different
+                       # 5 -> names match, addresses excluding subaddress details (refer RFC 5233) match
+
+                       my $sob_msg = "'From: $author' != 'Signed-off-by: $author_sob'";
+
+                       if ($authorsignoff == 0) {
+                               ERROR("NO_AUTHOR_SIGN_OFF",
+                                     "Missing Signed-off-by: line by nominal patch author '$author'\n");
+                       } elsif ($authorsignoff == 2) {
+                               CHK("FROM_SIGN_OFF_MISMATCH",
+                                   "From:/Signed-off-by: email comments mismatch: $sob_msg\n");
+                       } elsif ($authorsignoff == 3) {
+                               WARN("FROM_SIGN_OFF_MISMATCH",
+                                    "From:/Signed-off-by: email name mismatch: $sob_msg\n");
+                       } elsif ($authorsignoff == 4) {
+                               WARN("FROM_SIGN_OFF_MISMATCH",
+                                    "From:/Signed-off-by: email address mismatch: $sob_msg\n");
+                       } elsif ($authorsignoff == 5) {
+                               WARN("FROM_SIGN_OFF_MISMATCH",
+                                    "From:/Signed-off-by: email subaddress mismatch: $sob_msg\n");
+                       }
                }
        }