fix: lookup self by address if there is no fingerprint or gossip

src/receive_imf.rs

@@ -3747,6 +3747,9 @@ async fn add_or_lookup_key_contacts_by_address_list(
             fp.hex()
         } else if let Some(key) = gossiped_keys.get(addr) {
             key.dc_fingerprint().hex()
+        } else if context.is_self_addr(addr).await? {
+            contact_ids.push(Some(ContactId::SELF));
+            continue;
         } else {
             contact_ids.push(None);
             continue;

src/receive_imf/receive_imf_tests.rs

@@ -5302,3 +5302,48 @@ async fn test_outgoing_unencrypted_chat_assignment() {
     let chat = alice.create_email_chat(bob).await;
     assert_eq!(received.chat_id, chat.id);
 }
+
+/// Tests Bob receiving a message from Alice
+/// in a new group she just created
+/// with only Alice and Bob.
+///
+/// The message has no Autocrypt-Gossip
+/// headers and no Chat-Group-Member-Fpr header.
+/// Such messages were created by core 1.159.5
+/// when Alice has bcc_self disabled
+/// as Chat-Group-Member-Fpr header did not exist
+/// yet and Autocrypt-Gossip is not sent
+/// as there is only one recipient
+/// (Bob, and no additional Alice devices).
+///
+/// Bob should recognize self as being
+/// a member of the group by just the e-mail address.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_group_introduction_no_gossip() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let bob = &tcm.bob().await;
+
+    let received = receive_imf(
+        bob,
+        include_bytes!("../../test-data/message/group-introduction-no-gossip.eml"),
+        false,
+    )
+    .await
+    .unwrap()
+    .unwrap();
+    let msg = Message::load_from_db(bob, *received.msg_ids.last().unwrap())
+        .await
+        .unwrap();
+    assert_eq!(msg.text, "I created a group");
+    let chat = Chat::load_from_db(bob, msg.chat_id).await.unwrap();
+    assert_eq!(chat.typ, Chattype::Group);
+    assert_eq!(chat.blocked, Blocked::Request);
+    assert_eq!(chat.name, "Group!");
+    assert!(chat.is_encrypted(bob).await.unwrap());
+
+    let contacts = get_chat_contacts(bob, chat.id).await?;
+    assert_eq!(contacts.len(), 2);
+    assert!(chat.is_self_in_chat(bob).await?);
+
+    Ok(())
+}

test-data/message/group-introduction-no-gossip.eml

@@ -0,0 +1,65 @@
+Content-Type: multipart/encrypted; protocol="application/pgp-encrypted"; 
+	boundary="18566fe03178296e_f40510c3b59ace3_ecf843ae3ccd2b17"
+MIME-Version: 1.0
+From: <alice@example.org>
+To: <bob@example.net>
+Subject: [...]
+Date: Mon, 28 Jul 2025 14:15:14 +0000
+Message-ID: <48b9e9cc-2bae-4d41-89b4-a409e2c60c28@localhost>
+References: <48b9e9cc-2bae-4d41-89b4-a409e2c60c28@localhost>
+Chat-Version: 1.0
+Autocrypt: addr=alice@example.org; prefer-encrypt=mutual; keydata=mDMEXlh13RYJKwYBBAHaRw8BAQdAzfVIAleCXMJrq8VeLlEVof6ITCviMktKjmcBKAu4m5
+	 C0GUFsaWNlIDxhbGljZUBleGFtcGxlLm9yZz7CkgQQFggAOgUCaIeF8RYhBC5vossjtTLXKGNLWGSw
+	 j2Gp7ZRDAhsDAh4BBQsJCAcCBhUKCQgLAgQWAgMBAScCGQEACgkQZLCPYantlEM66gD/b9qi1/H1Cr
+	 UwwlW2akVX86Q0gX6isyKfuNu/CdTdzaQBAIHRxvwlBNZr56qMGL7CyVy6LmBslLlbQwAdclM9t9UE
+	 uDgEXlh13RIKKwYBBAGXVQEFAQEHQAbtyNbLZIUBTwqeW2W5tVbrusWLJ+nTUmtF7perLbYdAwEIB8
+	 J4BBgWCAAgBQJoh4XxAhsMFiEELm+iyyO1MtcoY0tYZLCPYantlEMACgkQZLCPYantlEPG2QD8DthL
+	 48j1wnjw+Kby7CmAm/M+Me82izk8dGNPn442jJ4A/2r+YmqfUPK2XDXPRwvVBAIz5bL44fe7gNkUUu
+	 XMnzkP
+
+
+--18566fe03178296e_f40510c3b59ace3_ecf843ae3ccd2b17
+Content-Type: application/pgp-encrypted; charset="utf-8"
+Content-Description: PGP/MIME version identification
+Content-Transfer-Encoding: 7bit
+
+Version: 1
+
+--18566fe03178296e_f40510c3b59ace3_ecf843ae3ccd2b17
+Content-Type: application/octet-stream; name="encrypted.asc"; 
+	charset="utf-8"
+Content-Description: OpenPGP encrypted message
+Content-Disposition: inline; filename="encrypted.asc";
+Content-Transfer-Encoding: 7bit
+
+-----BEGIN PGP MESSAGE-----
+
+wV4D5tq63hTeebASAQdAg7f2cyYQy+7Xrrlq4j3ik2Ba7L2sbh7Tt398Kke65Rkw
+sUscOFFConkBj7T5D8XS3e9dX5Bnf1z5jTj15OUZx/2iPTRQFtoVoRB6k6vt/qwq
+wcBMA+PY3JvEjuMiAQf/U9yB7kWhDMmFI7pMoktqqIvO8woKQG0dx2v1tzjIdtY/
+KlqMW8qpAqMHHalInGjj0LDDv4iWnNf8yTh71FyGQgipqH4FnYmbRoFW8iicMixN
+0ps6c6tBiZmyWDq2Ub9SIs9L/W2+vDlbyvFnow08MitOniZLC79KXB2ZRFwp7kOm
+1gqsZVvsy9fSM7oxXrxAtu2VNyp18emd6jAFWYAz2ISl2KuWYlmSJVexSvQWMRz/
+IkKWf9kOVAEuIeUnNo45S/DVb9uWQN3M1TrIdJ1BC+nEDBJokCWUGES6kchJc823
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+sR444bJS9V6MNDSuhKmvPvu4wCFZgNQPs4V51yBX8Rjpn/3xws+NpUtisTt5J+ji
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+Nv5aajaFKSEwAO9TNHNoP3LD5KxMPiCkRh888V3YhCOwTUfwJG8riWgeyFCN6Xor
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+k68Pi5WjMs/kH/3Wl5Octb8XYN++DiG7RH5JzWYRchURen8jgPjzJPIUI5t+C8w0
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+AIr0TjpOmkdL3TANYA5448gTR4Kq+FwhsxX+fHU6OxwxLBozMcBzvjReKdJko8D+
+joaTEZBFxyvQUub5/MXmuulTEDhwURgGMbIN0TukdYlhUBfvyJ/wl/U9aHWvk+dz
+3OJ6d9SqTKPPyluTPV7p3GEDy1AwAex5FrP8SxRGRHiMjVhlbwrQB89ZcUX376ge
+5MPc4wBn44baPluklYcQtk6kp62KuLpfuLT8VbiLDfKT2FoZzoAnUnw=
+=HN9M
+-----END PGP MESSAGE-----
+
+
+--18566fe03178296e_f40510c3b59ace3_ecf843ae3ccd2b17--