From d5fe53ef5734e5a5e0f6f7808fd300937ac86d96 Mon Sep 17 00:00:00 2001
From: Aram Drevekenin <aram@poor.dev>
Date: Tue, 4 Jan 2022 11:07:09 +0100
Subject: [PATCH] fix(tabs): dont panic when tab history is empty and closing
 tab (#990)

---
 zellij-server/src/screen.rs | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/zellij-server/src/screen.rs b/zellij-server/src/screen.rs
index 4f9636ce..cfc99518 100644
--- a/zellij-server/src/screen.rs
+++ b/zellij-server/src/screen.rs
@@ -237,14 +237,27 @@ impl Screen {
         &mut self,
         client_ids_and_mode_infos: Vec<(ClientId, ModeInfo)>,
     ) {
+        // this will panic if there are no more tabs (ie. if self.tabs.is_empty() == true)
         for (client_id, client_mode_info) in client_ids_and_mode_infos {
-            let client_previous_tab = self.tab_history.get_mut(&client_id).unwrap().pop().unwrap();
-            self.active_tab_indices
-                .insert(client_id, client_previous_tab);
-            self.tabs
-                .get_mut(&client_previous_tab)
-                .unwrap()
-                .add_client(client_id, Some(client_mode_info));
+            let client_tab_history = self.tab_history.entry(client_id).or_insert_with(Vec::new);
+            match client_tab_history.pop() {
+                Some(client_previous_tab) => {
+                    self.active_tab_indices
+                        .insert(client_id, client_previous_tab);
+                    self.tabs
+                        .get_mut(&client_previous_tab)
+                        .unwrap()
+                        .add_client(client_id, Some(client_mode_info));
+                }
+                None => {
+                    let next_tab_index = *self.tabs.keys().next().unwrap();
+                    self.active_tab_indices.insert(client_id, next_tab_index);
+                    self.tabs
+                        .get_mut(&next_tab_index)
+                        .unwrap()
+                        .add_client(client_id, Some(client_mode_info));
+                }
+            }
         }
     }
     fn move_clients_between_tabs(