fix(maestro): serialize shutdown finalization

crates/maestro-daemon/src/session.rs

@@ -7,7 +7,7 @@
 
 use std::collections::{HashMap, HashSet};
 use std::path::PathBuf;
-use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -195,6 +195,9 @@ struct Inner {
     /// client that reconnects never collides with the registration its
     /// previous socket has not finished releasing.
     next_viewport: AtomicU64,
+    /// Once daemon shutdown starts, it owns structured-session finalization.
+    /// Background passes must not classify those deliberate exits as natural.
+    shutting_down: AtomicBool,
 }
 
 impl SessionManager {
@@ -237,6 +240,7 @@ impl SessionManager {
                 events,
                 viewports: Mutex::new(Viewports::new()),
                 next_viewport: AtomicU64::new(0),
+                shutting_down: AtomicBool::new(false),
             }),
         }
     }
@@ -349,13 +353,17 @@ impl SessionManager {
     /// is on disk after the restart is truthful. tmux sessions are left
     /// alone — surviving a restart is what they are for.
     pub async fn shutdown(&self) {
+        if self.inner.shutting_down.swap(true, Ordering::AcqRel) {
+            return;
+        }
         let children: Vec<(Uuid, Arc<AcpSession>, Option<watch::Receiver<bool>>)> = {
             let sessions = self.inner.sessions.lock().await;
             sessions
                 .iter()
                 .filter_map(|(id, r)| {
-                    r.acp
-                        .clone()
+                    (r.session.status == SessionStatus::Running)
+                        .then_some(())
+                        .and_then(|()| r.acp.clone())
                         .map(|acp| (*id, acp, r.acp_event_pump.clone()))
                 })
                 .collect()
@@ -1438,6 +1446,9 @@ async fn probe_worktree(
 /// One pass of the liveness watcher: diff the in-memory session set against
 /// the tmux-reported one, and reap anything we still track but tmux has lost.
 async fn run_liveness_pass(inner: &Arc<Inner>) {
+    if inner.shutting_down.load(Ordering::Acquire) {
+        return;
+    }
     // Snapshot the in-memory ids first; if we own no sessions there is
     // nothing to reap and no reason to spawn a tmux subprocess (this also
     // avoids racing with the very first `new-session` that would otherwise
@@ -1497,6 +1508,9 @@ async fn run_liveness_pass(inner: &Arc<Inner>) {
 /// `SessionUpdated` only when `activity` or `foreground` actually changes — so a
 /// steady state produces no diffs. Runs on the existing liveness tick.
 async fn run_activity_pass(inner: &Arc<Inner>) {
+    if inner.shutting_down.load(Ordering::Acquire) {
+        return;
+    }
     let ids: Vec<Uuid> = {
         let sessions = inner.sessions.lock().await;
         if sessions.is_empty() {
@@ -1539,6 +1553,9 @@ async fn run_activity_pass(inner: &Arc<Inner>) {
 
         let updated = {
             let mut sessions = inner.sessions.lock().await;
+            if inner.shutting_down.load(Ordering::Acquire) {
+                return;
+            }
             let Some(rec) = sessions.get_mut(&id) else {
                 continue;
             };
@@ -1613,6 +1630,9 @@ async fn run_activity_pass(inner: &Arc<Inner>) {
 /// error must not read as "nothing blocks". Like the activity pass, this only
 /// emits `SessionUpdated` when the value actually changed.
 async fn run_blocked_work_pass(inner: &Arc<Inner>) {
+    if inner.shutting_down.load(Ordering::Acquire) {
+        return;
+    }
     let targets: Vec<(Uuid, (PathBuf, PathBuf))> = {
         let sessions = inner.sessions.lock().await;
         sessions
@@ -1640,6 +1660,9 @@ async fn run_blocked_work_pass(inner: &Arc<Inner>) {
         };
         let updated = {
             let mut sessions = inner.sessions.lock().await;
+            if inner.shutting_down.load(Ordering::Acquire) {
+                return;
+            }
             let Some(rec) = sessions.get_mut(&id) else {
                 continue;
             };
@@ -1672,6 +1695,9 @@ async fn run_blocked_work_pass(inner: &Arc<Inner>) {
 /// [`SessionManager::recover`] adopts only what tmux still holds. Structured
 /// sessions stopped for daemon shutdown retain their sidecars for ACP recovery.
 async fn mark_session_dead(inner: &Arc<Inner>, id: Uuid) {
+    if inner.shutting_down.load(Ordering::Acquire) {
+        return;
+    }
     mark_session_dead_with_worktree_settlement(inner, id, true).await;
 }