From 136dbf1a60fca5e7d77e0644cbbf773bca6ce99a Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@jermolene.com>
Date: Fri, 3 Jan 2020 10:39:37 +0000
Subject: [PATCH] Fix bug with importvariables and empty set widgets

A self-closing set widget doesn't have a "children" property.
---
 core/modules/widgets/importvariables.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/modules/widgets/importvariables.js b/core/modules/widgets/importvariables.js
index cdb351f8d..86559ef25 100644
--- a/core/modules/widgets/importvariables.js
+++ b/core/modules/widgets/importvariables.js
@@ -66,7 +66,7 @@ ImportVariablesWidget.prototype.execute = function(tiddlerList) {
 					params: parseTreeNode.params,
 					isMacroDefinition: parseTreeNode.isMacroDefinition
 				});
-				parseTreeNode = parseTreeNode.children[0];
+				parseTreeNode = parseTreeNode.children && parseTreeNode.children[0];
 			}
 		} 
 	});