From 49d3c8fe29aad9cf540ce85694cdfad6523e00b4 Mon Sep 17 00:00:00 2001
From: Mike Mueller <mike.mueller@cstudio.ch>
Date: Wed, 6 May 2026 23:40:28 +0200
Subject: [PATCH] more breadcrumbs

---
 src/common.rs              | 22 ++++++++++++++++++++++
 src/rendezvous_mediator.rs |  5 +++++
 2 files changed, 27 insertions(+)

diff --git a/src/common.rs b/src/common.rs
index 321d5105b..2a0c38ee4 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -123,6 +123,7 @@ impl Drop for SimpleCallOnReturn {
 
 pub fn global_init() -> bool {
     install_panic_hook();
+    install_heartbeat();
     #[cfg(target_os = "linux")]
     {
         if !crate::platform::linux::is_x11() {
@@ -132,6 +133,27 @@ pub fn global_init() -> bool {
     true
 }
 
+/// Background thread that logs a heartbeat every second. Used purely to pin
+/// down silent process exits — if the heartbeat stops, the process died at
+/// that timestamp, and we can correlate with what other threads were doing.
+/// Uses a counter so we can also tell if logging itself is wedged (counter
+/// keeps incrementing) vs the whole process is gone (no more lines).
+fn install_heartbeat() {
+    use std::sync::Once;
+    static INIT: Once = Once::new();
+    INIT.call_once(|| {
+        std::thread::spawn(|| {
+            let pid = std::process::id();
+            let mut tick: u64 = 0;
+            loop {
+                tick += 1;
+                log::info!("heartbeat: pid={pid} tick={tick}");
+                std::thread::sleep(std::time::Duration::from_secs(1));
+            }
+        });
+    });
+}
+
 /// Capture Rust panics so they survive the windows-subsystem build.
 ///
 /// In release we have `panic = 'abort'` and `windows_subsystem = "windows"`,
diff --git a/src/rendezvous_mediator.rs b/src/rendezvous_mediator.rs
index 9d9a7ce57..4fa751d7b 100644
--- a/src/rendezvous_mediator.rs
+++ b/src/rendezvous_mediator.rs
@@ -219,10 +219,14 @@ impl RendezvousMediator {
             };
             select! {
                 n = socket.next() => {
+                    log::info!("breadcrumb: udp socket.next() returned");
                     match n {
                         Some(Ok((bytes, _))) => {
+                            log::info!("breadcrumb: udp packet received, {} bytes", bytes.len());
                             if let Ok(msg) = Message::parse_from_bytes(&bytes) {
+                                log::info!("breadcrumb: before handle_resp");
                                 rz.handle_resp(msg.union, Sink::Framed(&mut socket, &addr), &server, &mut update_latency).await?;
+                                log::info!("breadcrumb: after handle_resp");
                             } else {
                                 log::debug!("Non-protobuf message bytes received: {:?}", bytes);
                             }
@@ -234,6 +238,7 @@ impl RendezvousMediator {
                     }
                 },
                 _ = timer.tick() => {
+                    log::info!("breadcrumb: udp timer.tick()");
                     if SHOULD_EXIT.load(Ordering::SeqCst) {
                         break;
                     }