Check sorting of MAINTAINERS.

contrib/ChangeLog:

	* check-MAINTAINERS.py: New file.

contrib/check-MAINTAINERS.py

+#!/usr/bin/env python3
+
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING.  If not, write to
+# the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+# Boston, MA 02110-1301, USA.
+
+# Check that names in the file are sorted
+# alphabetically by surname.
+
+import locale
+import sys
+from difflib import ndiff
+from itertools import dropwhile, takewhile
+
+import unidecode
+
+locale.setlocale(locale.LC_ALL, 'en_US.utf8')
+
+exit_code = 0
+
+if len(sys.argv) != 2:
+    print('Usage: ./check-MAINTAINERS.py path-to/MAINTAINERS')
+    sys.exit(1)
+
+
+def sort_by_surname(line):
+    name = line.split('\t')[0]
+    parts = name.split()
+    surname = parts[-1]
+
+    # Special-case some names
+    if name == 'Stefan Schulze Frielinghaus':
+        surname = parts[1]
+    elif name == 'Kris Van Hees':
+        surname = parts[1]
+    elif surname == "d'Humieres":
+        surname = 'Humieres'
+
+    # Remove accents
+    return (unidecode.unidecode(surname), line)
+
+
+def has_tab(line):
+    return '\t' in line
+
+
+def is_empty(line):
+    return line
+
+
+def check_group(name, lines):
+    global exit_code
+
+    for line in lines:
+        if line.startswith(' '):
+            print(f'Line should not start with space: "{line}"')
+            exit_code = 2
+
+    lines = [line + '\n' for line in lines]
+    sorted_lines = sorted(lines, key=sort_by_surname)
+    if lines != sorted_lines:
+        exit_code = 1
+        diff = ndiff(lines, sorted_lines)
+        print(f'Wrong order for {name}:\n')
+        print(''.join(diff))
+    else:
+        print(f'{name} are fine!')
+
+
+lines = open('MAINTAINERS').read().splitlines()
+
+needle = 'Global Reviewers'
+lines = list(dropwhile(lambda x: x.strip() != needle, lines))
+lines = lines[2:]
+
+chunk = list(takewhile(is_empty, lines))
+check_group(needle, chunk)
+
+needle = 'Write After Approval'
+lines = list(dropwhile(lambda x: needle not in x, lines))
+lines = lines[2:]
+
+chunk = list(takewhile(is_empty, lines))
+check_group(needle, chunk)
+
+needle = 'Bug database only accounts'
+lines = list(dropwhile(lambda x: needle not in x, lines))
+lines = lines[2:]
+
+chunk = list(takewhile(is_empty, lines))
+check_group(needle, chunk)
+
+needle = 'Contributing under the DCO'
+lines = list(dropwhile(lambda x: needle not in x, lines))[1:]
+lines = list(dropwhile(lambda x: not has_tab(x), lines))
+check_group(needle, lines)
+
+sys.exit(exit_code)