[PATCH v5 9/9] scripts/checkpatch: reject license boilerplate on new files

["Daniel P. Berrangé" <berrange@redhat.com>]

The previous commit mandates use of SPDX-License-Identifier on common
source files, and encourages it on all other files.

Some contributors are none the less still also including the license
boilerplate text. This is redundant and will potentially cause
trouble if inconsistent with the SPDX declaration.

Match common boilerplate text blurbs and report them as invalid,
for newly added files.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 scripts/checkpatch.pl | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index dc2c3e6aa1..17b8db40ad 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -365,6 +365,18 @@ our @typeList = (
 	qr{guintptr},
 );
 
+# Match text found in common license boilerplate comments:
+# for new files the SPDX-License-Identifier line is sufficient.
+our @LICENSE_BOILERPLATE = (
+	"licensed under the terms of the GNU GPL",
+	"under the terms of the GNU General Public License",
+	"under the terms of the GNU Lesser General Public",
+	"Permission is hereby granted, free of charge",
+	"GNU GPL, version 2 or later",
+	"See the COPYING file"
+);
+our $LICENSE_BOILERPLATE_RE = join("|", @LICENSE_BOILERPLATE);
+
 # Load common spelling mistakes and build regular expression list.
 my $misspellings;
 my %spelling_fix;
@@ -1497,6 +1509,13 @@ sub process_end_of_file {
 			     "' need 'SPDX-License-Identifier'?");
 		}
 	}
+	if ($fileinfo->{action} eq "new" &&
+	    exists $fileinfo->{facts}->{sawboilerplate}) {
+		ERROR("New file '" . $fileinfo->{filenew} . "' must " .
+		      "not have license boilerplate header text, only " .
+		      "the SPDX-License-Identifier, unless this file was " .
+		      "copied from existing code already having such text.");
+	}
 }
 
 sub process {
@@ -1799,6 +1818,10 @@ sub process {
 			&checkspdx($realfile, $1);
 		}
 
+		if ($rawline =~ /$LICENSE_BOILERPLATE_RE/) {
+			$fileinfo->{facts}->{sawboilerplate} = 1;
+		}
+
 		if ($rawline =~ m,(SPDX-[a-zA-Z0-9-_]+):,) {
 			my $tag = $1;
 			my @permitted = qw(
-- 
2.49.0