From fc1a9925a6f3659f575aab447409cb018e53da16 Mon Sep 17 00:00:00 2001
From: Anton Akhmerov <anton.akhmerov@gmail.com>
Date: Mon, 19 Oct 2020 09:25:04 +0200
Subject: [PATCH] show an error message when the kernel is dead

---
 src/thebelab.js | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/thebelab.js b/src/thebelab.js
index 28389a05..011f9f5d 100644
--- a/src/thebelab.js
+++ b/src/thebelab.js
@@ -239,7 +239,16 @@ function renderCell(element, options) {
       events.trigger("request-kernel");
     }
     kernelPromise.then((kernel) => {
-      outputArea.future = kernel.requestExecute({ code: code });
+      try {
+        outputArea.future = kernel.requestExecute({ code: code });
+      } catch (error) {
+        outputArea.model.clear();
+        outputArea.model.add({
+          output_type: "stream",
+          name: "stderr",
+          text: `Failed to execute. ${error} Please refresh the page.`,
+        });
+      }
     });
     return false;
   }