fix: removed unnecessary regenerate logic for sessions and use the same logic for all contexts; prevents a panic on empty message list

src/client/message.rs

@@ -227,6 +227,9 @@ pub fn patch_messages(messages: &mut Vec<Message>, model: &Model) {
 }
 
 pub fn extract_system_message(messages: &mut Vec<Message>) -> Option<String> {
+    if messages.is_empty() {
+        return None;
+    }
     if messages[0].role.is_system() {
         let system_message = messages.remove(0);
         return Some(system_message.content.to_text());

src/config/session.rs

@@ -628,15 +628,6 @@ impl Session {
         let mut messages = self.messages.clone();
         if input.continue_output().is_some() {
             return messages;
-        } else if input.regenerate() {
-            while let Some(last) = messages.last() {
-                if !last.role.is_user() {
-                    messages.pop();
-                } else {
-                    break;
-                }
-            }
-            return messages;
         }
         let mut need_add_msg = true;
         let len = messages.len();