From a3cb58484fd9629ee534bdb62ab3e1c2a11e4531 Mon Sep 17 00:00:00 2001
From: link2xt <link2xt@testrun.org>
Date: Sun, 21 Jul 2024 02:19:51 +0000
Subject: [PATCH] feat: use `[...]` for protected subject

This subject is going to be standardized in
<https://datatracker.ietf.org/doc/draft-ietf-lamps-header-protection/>
and is already used in K-9 Mail:
<https://github.com/thunderbird/thunderbird-android/pull/8014>
---
 src/mimefactory.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mimefactory.rs b/src/mimefactory.rs
index 843462b3c..25c43d392 100644
--- a/src/mimefactory.rs
+++ b/src/mimefactory.rs
@@ -774,7 +774,7 @@ impl MimeFactory {
 
                 match header_name.as_str() {
                     "subject" => {
-                        unprotected_headers.push(Header::new(header.name, "...".to_string()));
+                        unprotected_headers.push(Header::new(header.name, "[...]".to_string()));
                     }
                     "date"
                     | "in-reply-to"
@@ -2511,6 +2511,7 @@ mod tests {
             .await?;
         let sent = bob.send_msg(chat, &mut msg).await;
         assert!(msg.get_showpadlock());
+        assert!(sent.payload.contains("\r\nSubject: [...]\r\n"));
 
         let mime = MimeMessage::from_bytes(&alice, sent.payload.as_bytes(), None).await?;
         let mut payload = str::from_utf8(&mime.decoded_data)?.splitn(2, "\r\n\r\n");