1 files changed, 90 insertions, 0 deletions
diff --git a/patch-save.py b/patch-save.py
new file mode 100755
index 0000000..1c0516f
--- /dev/null
+++ b/patch-save.py
@@ -0,0 +1,90 @@
+#!/usr/bin/python3
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2022 Laurent Pinchart
+#
+# Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+#
+# Patch save script for mutt that handles mailman From header mangling.
+#
+# To install, copy the script to ~/.mutt/, and add the following lines to your
+# .muttrc to bind to ctrl-h.
+#
+# set pipe_split=yes
+# macro index \Ch "<enter-command>unset wait_key<enter>
+#   <enter-command>set pipe_decode<enter>
+#   <tag-prefix><pipe-entry>~/.mutt/patch-save.py<enter>
+#   <enter-command>unset pipe_decode<enter>
+#   <enter-command>set wait_key<enter>" "output git patches"
+#
+
+import email
+import pathlib
+import re
+import sys
+
+
+def sanitize(s):
+    out = ''
+
+    for c in s:
+        if c in '[]':
+            continue
+
+        if c in "'":
+            c = '.'
+        elif c in '/:':
+            c = '-'
+        elif c in '*()" \t\n\r':
+            c = '_'
+
+        out += c
+
+    return out
+
+
+def main(argv):
+
+    # Parse the message from stdin as binary, as we can't assume any particular
+    # encoding.
+    msg = email.message_from_binary_file(sys.stdin.buffer)
+
+    # mailman can mangle the From header to work around DMARC rejection rules.
+    # It then formats From as "Name via mailing-list <mailing-list@domain>" and
+    # stores the original sender in the Reply-to header. Restore the original
+    # author in the From header to please git-am.
+    from_header = msg.get('From')
+    reply_to = msg.get('Reply-to')
+    if reply_to and ' via ' in from_header:
+        msg.replace_header('From', reply_to)
+
+    subject = msg.get('Subject')
+    if not subject:
+        return 1
+
+    # The subject can be an str instance or an email.header.Header instance.
+    # Convert it to str in all cases.
+    subject = str(subject)
+
+    # Strip everything before the [PATCH] or [RESEND] tag.
+    match = re.search(r'\[(PATCH|RESEND) [^]]*\].*', subject)
+    if match:
+        subject = match.group(0)
+
+    # Sanitize the subject.
+    subject = sanitize(subject)
+
+    subject = subject.replace('..', '.')
+    subject = subject.replace('-_', '_')
+    subject = subject.replace('__', '_')
+
+    subject = subject.strip()
+    subject = subject.rstrip('.')
+
+    file_name = pathlib.Path.home() / '.maildir' / 'patches' / (subject + '.patch')
+    open(file_name, 'wb').write(bytes(msg))
+
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))