From 00e1d00dfa5b64f19a59386fdf3fe4fca7a1d346 Mon Sep 17 00:00:00 2001
From: holger krekel <holger@merlinux.eu>
Date: Sat, 25 Jul 2026 23:15:27 +0200
Subject: [PATCH] fix: send MDNs to all authentic relays of a contact, not just
 whatever get_addr() returns.

---
 src/mimefactory.rs                   |  4 +++-
 src/mimefactory/mimefactory_tests.rs | 30 +++++++++++++++++++++++++++-
 src/smtp.rs                          |  9 +++++----
 3 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/src/mimefactory.rs b/src/mimefactory.rs
index 72ecd3468..7abae8621 100644
--- a/src/mimefactory.rs
+++ b/src/mimefactory.rs
@@ -578,10 +578,12 @@ impl MimeFactory {
         let timestamp = time();
 
         let addr = contact.get_addr().to_string();
+        let mut recipients = vec![addr.clone()];
         let encryption_pubkeys = if from_id == ContactId::SELF {
             Some(Vec::new())
         } else if contact.is_key_contact() {
             if let Some(key) = contact.public_key(context).await? {
+                recipients = addresses_from_public_key(&key).unwrap_or_else(|| vec![addr.clone()]);
                 Some(vec![(addr.clone(), key)])
             } else {
                 Some(Vec::new())
@@ -595,7 +597,7 @@ impl MimeFactory {
             from_displayname: "".to_string(),
             sender_displayname: None,
             selfstatus: "".to_string(),
-            recipients: vec![addr],
+            recipients,
             encryption_pubkeys,
             to: vec![("".to_string(), contact.get_addr().to_string())],
             past_members: vec![],
diff --git a/src/mimefactory/mimefactory_tests.rs b/src/mimefactory/mimefactory_tests.rs
index a508fa455..937fdacbd 100644
--- a/src/mimefactory/mimefactory_tests.rs
+++ b/src/mimefactory/mimefactory_tests.rs
@@ -14,8 +14,9 @@ use crate::chat::{
 };
 use crate::chatlist::Chatlist;
 use crate::constants;
-use crate::contact::{Origin, import_vcard};
+use crate::contact::{Origin, import_public_key, import_vcard};
 use crate::headerdef::HeaderDef;
+use crate::key::{load_self_secret_key, secret_key_to_public_key};
 use crate::message;
 use crate::mimeparser::MimeMessage;
 use crate::receive_imf::receive_imf;
@@ -327,6 +328,33 @@ async fn test_mdn_create_encrypted() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_mdn_sent_to_all_relays() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let bob = &tcm.bob().await;
+
+    let rcvd = tcm.send_recv_accept(bob, alice, "Heyho").await;
+
+    // Bob's key gets a second relay address and Alice merges the newer key.
+    let bob_secret_key = load_self_secret_key(bob).await?;
+    let bob_public_key = secret_key_to_public_key(
+        bob,
+        bob_secret_key,
+        u32::try_from(time())? + 100,
+        "bob@example.net",
+        "bob@example.net,bob@relay2.example",
+    )?;
+    import_public_key(alice, &bob_public_key).await?;
+
+    let mimefactory = MimeFactory::from_mdn(alice, rcvd.from_id, rcvd.rfc724_mid, vec![]).await?;
+    let mut recipients = mimefactory.recipients();
+    recipients.sort();
+    assert_eq!(recipients, vec!["bob@example.net", "bob@relay2.example"]);
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_mdn_autocrypt_throttle() -> Result<()> {
     async fn mdn_has_aheader(
diff --git a/src/smtp.rs b/src/smtp.rs
index 9c29fb7e5..0655c761a 100644
--- a/src/smtp.rs
+++ b/src/smtp.rs
@@ -596,13 +596,14 @@ async fn send_mdn_rfc724_mid(
     )
     .await?;
     let encrypted = mimefactory.will_be_encrypted();
+    let mut recipients = if contact_id == ContactId::SELF {
+        Vec::new()
+    } else {
+        mimefactory.recipients()
+    };
     let rendered_msg = Box::pin(mimefactory.render(context)).await?;
     let body = rendered_msg.message;
 
-    let mut recipients = Vec::new();
-    if contact_id != ContactId::SELF {
-        recipients.push(contact.get_addr().to_string());
-    }
     if context.get_config_bool(Config::BccSelf).await? {
         add_self_recipients(context, &mut recipients, encrypted).await?;
     }