Fix Neovim connection deadlock by dropping NVIM_CONN lock across await boundary

nvim-core/src/lib.rs

@@ -126,10 +126,12 @@ pub struct NvimRequest {
 static NVIM_CONN: LazyLock<Arc<Mutex<Option<mpsc::Sender<NvimRequest>>>>> = LazyLock::new(|| Arc::new(Mutex::new(None)));
 
 async fn get_nvim_connection() -> Result<mpsc::Sender<NvimRequest>, String> {
-    let mut conn_lock = NVIM_CONN.lock().await;
-    if let Some(sender) = conn_lock.as_ref() {
-        if !sender.is_closed() {
-            return Ok(sender.clone());
+    {
+        let conn_lock = NVIM_CONN.lock().await;
+        if let Some(sender) = conn_lock.as_ref() {
+            if !sender.is_closed() {
+                return Ok(sender.clone());
+            }
         }
     }
 
@@ -228,6 +230,7 @@ async fn get_nvim_connection() -> Result<mpsc::Sender<NvimRequest>, String> {
         }
     });
 
+    let mut conn_lock = NVIM_CONN.lock().await;
     *conn_lock = Some(tx.clone());
     Ok(tx)
 }