From a09fd4577a4ed27ffb2b6b0ce48f90377ac7a53c Mon Sep 17 00:00:00 2001
From: Simon Laux <Simon-Laux@users.noreply.github.com>
Date: Mon, 15 Dec 2025 11:35:23 +0100
Subject: [PATCH] fix: add explicit limit for adding relays (5 at the moment)
 (#7611)

closes https://github.com/chatmail/core/issues/7608
---
 .../tests/test_multitransport.py              | 22 +++++++++++++++++++
 src/configure.rs                              | 16 ++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/deltachat-rpc-client/tests/test_multitransport.py b/deltachat-rpc-client/tests/test_multitransport.py
index bdcca57ec..869b2de7b 100644
--- a/deltachat-rpc-client/tests/test_multitransport.py
+++ b/deltachat-rpc-client/tests/test_multitransport.py
@@ -221,3 +221,25 @@ def test_recognize_self_address(acfactory) -> None:
     bob_chat.send_text("Hello!")
     msg = alice.wait_for_incoming_msg().get_snapshot()
     assert msg.chat == alice.create_chat(bob)
+
+
+def test_transport_limit(acfactory) -> None:
+    """Test transports limit."""
+    account = acfactory.get_online_account()
+    qr = acfactory.get_account_qr()
+
+    limit = 5
+
+    for _ in range(1, limit):
+        account.add_transport_from_qr(qr)
+
+    assert len(account.list_transports()) == limit
+
+    with pytest.raises(JsonRpcError):
+        account.add_transport_from_qr(qr)
+
+    second_addr = account.list_transports()[1]["addr"]
+    account.delete_transport(second_addr)
+
+    # test that adding a transport after deleting one works again
+    account.add_transport_from_qr(qr)
diff --git a/src/configure.rs b/src/configure.rs
index b0f32392e..e72315e7e 100644
--- a/src/configure.rs
+++ b/src/configure.rs
@@ -45,6 +45,10 @@ use crate::transport::{
 use crate::{EventType, stock_str};
 use crate::{chat, provider};
 
+/// Maximum number of relays
+/// see <https://github.com/chatmail/core/issues/7608>
+pub(crate) const MAX_TRANSPORT_RELAYS: usize = 5;
+
 macro_rules! progress {
     ($context:tt, $progress:expr, $comment:expr) => {
         assert!(
@@ -283,6 +287,18 @@ impl Context {
                     "To use additional relays, set the legacy option \"Settings / Advanced / Show Classic Emails\" to \"All\"."
                 );
             }
+
+            if self
+                .sql
+                .count("SELECT COUNT(*) FROM transports", ())
+                .await?
+                >= MAX_TRANSPORT_RELAYS
+            {
+                bail!(
+                    "You have reached the maximum number of relays ({}).",
+                    MAX_TRANSPORT_RELAYS
+                )
+            }
         }
 
         let provider = match configure(self, param).await {