From 01cb37c269da731a2f27bf9dd47b347726f63190 Mon Sep 17 00:00:00 2001
From: Rick Hennigan <richardh@wolfram.com>
Date: Thu, 25 Jan 2024 13:46:36 -0500
Subject: [PATCH] If the existing chat output has been removed before a new
 paged output can be created, just create a new chat output

---
 Source/Chatbook/SendChat.wl | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/Source/Chatbook/SendChat.wl b/Source/Chatbook/SendChat.wl
index 382b691e..16385f40 100644
--- a/Source/Chatbook/SendChat.wl
+++ b/Source/Chatbook/SendChat.wl
@@ -1654,9 +1654,14 @@ createNewChatOutput // endDefinition;
 prepareChatOutputPage // beginDefinition;
 
 prepareChatOutputPage[ target_CellObject, cell_Cell ] := Enclose[
-    Module[ { prevCellExpr, prevPage, encoded, pageData, newCellObject },
+    Catch @ Module[ { prevCellExpr, prevPage, encoded, pageData, newCellObject },
 
-        prevCellExpr = ConfirmMatch[ NotebookRead @ target, _Cell, "NotebookRead" ];
+        prevCellExpr = ConfirmMatch[ NotebookRead @ target, _Cell | $Failed, "NotebookRead" ];
+
+        If[ FailureQ @ prevCellExpr,
+            (* The target cell is gone, so just create a new one instead of trying to page outputs: *)
+            Throw @ cellPrint @ cell
+        ];
 
         prevPage = ConfirmMatch[
             Replace[ First @ prevCellExpr, text_String :> TextData @ { text } ],
@@ -1691,7 +1696,7 @@ prepareChatOutputPage[ target_CellObject, cell_Cell ] := Enclose[
         CurrentValue[ newCellObject, { TaggingRules, "PageData" } ] = pageData;
         newCellObject
     ],
-    throwInternalFailure[ prepareChatOutputPage[ target, cell ], ## ] &
+    throwInternalFailure
 ];
 
 prepareChatOutputPage // endDefinition;