refresh peers after stall

1 files changed, 38 insertions, 0 deletions

diff --git a/src/simtest/timing.rs b/src/simtest/timing.rs
index 25ecf89..e4981dd 100644
--- a/src/simtest/timing.rs
+++ b/src/simtest/timing.rs
@@ -146,6 +146,44 @@ async fn stalled_catch_up_source_is_replaced() {
     assert!(sources >= 2, "{sources} catch-up sources");
 }
 
+/// A joining node whose only known peer stalls as its catch-up source asks it again
+/// (a fresh HELLO): the reply lists the peers that joined meanwhile, and one of them
+/// takes over.
+#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
+async fn stalled_source_refreshes_the_peer_list() {
+    let sim = Sim::new(7);
+    let a = sim.start("a", &[], Start::Genesis);
+    let a = &a;
+    sim.wait_ready(&[a], SOON).await;
+    write(a, "data", json!("x")).await;
+
+    // c knows only a, which lists nobody: there is nobody else yet.
+    sim.net.set_link(
+        "a",
+        "c",
+        LinkParams {
+            drop: vec![MessageKind::Sync],
+            ..LinkParams::default()
+        },
+    );
+    let c = sim.start("c", &["a"], Start::Join);
+    let c = &c;
+    sim.wait_until("c knows a", SOON, move || async move {
+        c.get_peer_state("a").await.is_some()
+    })
+    .await;
+
+    // b joins meanwhile; c hears of it only by asking a again (after giving it up, or
+    // earlier if the keepalive heal re-handshakes first).
+    let b = sim.start("b", &["a"], Start::Join);
+    let b = &b;
+    sim.wait_ready(&[b], SOON).await;
+
+    sim.wait_ready(&[c], LOSSY).await;
+    assert_eq!(read(c, "data").await, Some(json!("x")));
+    assert!(c.get_peer_state("b").await.is_some());
+}
+
 /// A peer that hears nothing for `dormant_after` is dormant; once messages flow again
 /// it is active, re-handshakes, and syncs what it missed.
 #[tokio::test(flavor = "multi_thread", worker_threads = 4)]