fix: preserve sessions after interrupted pane exits (#3418)

* fix: preserve sessions when pane shells are signaled

refs #3415

* fix: preserve shutdown checkpoints across platforms

refs #3415

---------

Co-authored-by: Jonathan Liebig <jonathan.liebig@gmail.com>

3 files changed, 20 insertions, 5 deletions

diff --git a/src/server/headless.rs b/src/server/headless.rs
index abaca0aa..2d652378 100644
--- a/src/server/headless.rs
+++ b/src/server/headless.rs
@@ -721,7 +721,7 @@ impl HeadlessServer {
 
         // Save session on exit.
         if self.app.policy.persist_session {
-            self.app.save_session_now();
+            self.app.save_session_on_shutdown();
         }
 
         info!("headless server exiting");
diff --git a/src/server/headless/notifications.rs b/src/server/headless/notifications.rs
index dd661809..ddf9a9b3 100644
--- a/src/server/headless/notifications.rs
+++ b/src/server/headless/notifications.rs
@@ -663,7 +663,7 @@ impl HeadlessServer {
                 }
                 true
             }
-            AppEvent::PaneDied { pane_id }
+            AppEvent::PaneDied { pane_id, .. }
             | AppEvent::WorktreeRuntimeRestoreFailed { pane_id, .. } => {
                 let focus_before = self.shell_focus_targets();
                 let focused_tabs_before = self.focused_shell_tabs();
diff --git a/src/server/headless/tests/mod.rs b/src/server/headless/tests/mod.rs
index 5e0e5d01..63f7264d 100644
--- a/src/server/headless/tests/mod.rs
+++ b/src/server/headless/tests/mod.rs
@@ -3614,7 +3614,12 @@ async fn pane_death_reconciles_each_client_view_and_focus() {
     server.clients.get_mut(&71).unwrap().outer_terminal_focus = Some(true);
     server.clients.get_mut(&72).unwrap().outer_terminal_focus = Some(false);
 
-    assert!(server.handle_internal_event_with_forwarding(AppEvent::PaneDied { pane_id: dead_pane }));
+    assert!(
+        server.handle_internal_event_with_forwarding(AppEvent::PaneDied {
+            pane_id: dead_pane,
+            exit_reason: crate::platform::ChildExitReason::Exited
+        })
+    );
 
     assert_eq!(
         server.shell_tab_id_for_client(71).as_deref(),
@@ -3678,7 +3683,12 @@ async fn pane_death_reapplies_controller_geometry() {
     let shrunk = server.app.state.workspaces[0].test_runtimes[&first_pane].current_size();
     assert!(shrunk.0 < 46);
 
-    assert!(server.handle_internal_event_with_forwarding(AppEvent::PaneDied { pane_id: dead_pane }));
+    assert!(
+        server.handle_internal_event_with_forwarding(AppEvent::PaneDied {
+            pane_id: dead_pane,
+            exit_reason: crate::platform::ChildExitReason::Exited
+        })
+    );
 
     let runtime = &server.app.state.workspaces[0].test_runtimes[&first_pane];
     let grown = runtime.current_size();
@@ -3858,7 +3868,12 @@ fn expected_worktree_runtime_exit_does_not_release_agent() {
         .pending_worktree_remove_runtime_exits
         .insert(pane_id, 1);
 
-    assert!(server.handle_internal_event_with_forwarding(AppEvent::PaneDied { pane_id }));
+    assert!(
+        server.handle_internal_event_with_forwarding(AppEvent::PaneDied {
+            pane_id,
+            exit_reason: crate::platform::ChildExitReason::Exited
+        })
+    );
 
     assert_eq!(
         server.app.state.terminals[&terminal_id].state,