From 2ea093170c9b637e4189cb2f95941eff717e8867 Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Mon, 15 Mar 2021 06:37:46 -0700
Subject: [PATCH] mux: avoid panic if prune_dead_windows is called indirectly

refs: #542
---
 mux/src/lib.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/mux/src/lib.rs b/mux/src/lib.rs
index 46e915a95..13555459a 100644
--- a/mux/src/lib.rs
+++ b/mux/src/lib.rs
@@ -361,7 +361,13 @@ impl Mux {
         let dead_tab_ids: Vec<TabId>;
 
         {
-            let mut windows = self.windows.borrow_mut();
+            let mut windows = match self.windows.try_borrow_mut() {
+                Ok(w) => w,
+                Err(_) => {
+                    // It's ok if our caller already locked it; we can prune later.
+                    return;
+                }
+            };
             for (window_id, win) in windows.iter_mut() {
                 win.prune_dead_tabs(&live_tab_ids);
                 if win.is_empty() {