From 87dac59f8407ba5d74e52bf223c1b9509aa679ab Mon Sep 17 00:00:00 2001
From: dgp <dgp@users.sourceforge.net>
Date: Fri, 16 Nov 2018 17:44:47 +0000
Subject: [PATCH 480/693] Crash prevention. Still buggy, now test text-11a.22
 fails instead of crashing.

---
 generic/tkText.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/generic/tkText.c b/generic/tkText.c
index 4c536a22d..a0de1d5d2 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -5538,6 +5538,15 @@ RunAfterSyncCmd(
 	return;
     }
 
+    if (textPtr->afterSyncCmd == NULL) {
+	/*
+	 * [Bug 0a9c9151b5] Probably should have idle handlers coded so that
+	 * this cannot happen, but a safety check here at least prevents a
+	 * crash.
+	 */
+	return;
+    }
+
     Tcl_Preserve((ClientData) textPtr->interp);
     code = Tcl_EvalObjEx(textPtr->interp, textPtr->afterSyncCmd, TCL_EVAL_GLOBAL);
     if (code == TCL_ERROR) {
-- 
2.19.1