From 280701fbde340c15b6a081333984bf9e2fb684d9 Mon Sep 17 00:00:00 2001
From: Saq Imtiaz <saq.imtiaz@gmail.com>
Date: Sat, 28 Mar 2026 13:04:29 +0100
Subject: [PATCH] Fixes MVV's so that getVariableInfo returns undefined 
 (#9765)

* wip: non-existent variables as attributes should be undefined

* wip: non-existent variables as attributes should be undefined

* tests: added missing test

* fix: restore mistakenly commited files

* fix: whitespace
---
 core/modules/widgets/action-log.js                  |  4 ++--
 core/modules/widgets/widget.js                      |  4 ++--
 .../transclude/MissingTiddlerAttributeVariable.tid  | 13 +++++++++++++
 3 files changed, 17 insertions(+), 4 deletions(-)
 create mode 100644 editions/test/tiddlers/tests/data/transclude/MissingTiddlerAttributeVariable.tid

diff --git a/core/modules/widgets/action-log.js b/core/modules/widgets/action-log.js
index b9b9c52675..a8af05a493 100644
--- a/core/modules/widgets/action-log.js
+++ b/core/modules/widgets/action-log.js
@@ -61,7 +61,7 @@ LogWidget.prototype.log = function() {
 	$tw.utils.each(this.parseTreeNode.attributes,function(attribute,name) {
 		if(name.substring(0,2) !== "$$") {
 			var resultList = self.computeAttribute(attribute,{asList: true});
-			if(resultList.length <= 1) {
+			if(resultList && resultList.length <= 1) {
 				data[name] = resultList[0] || "";
 			} else {
 				data[name] = resultList;
@@ -75,7 +75,7 @@ LogWidget.prototype.log = function() {
 			allVars[v] = variable.value;
 		} else {
 			var variableInfo = this.getVariableInfo(v);
-			allVars[v] = variableInfo.resultList.length > 1 ? variableInfo.resultList : variableInfo.text;
+			allVars[v] = variableInfo && variableInfo.resultList && variableInfo.resultList.length > 1 ? variableInfo.resultList : variableInfo.text;
 		}
 	}
 	if(this.filter) {
diff --git a/core/modules/widgets/widget.js b/core/modules/widgets/widget.js
index da25cf613e..e1dbb5296e 100755
--- a/core/modules/widgets/widget.js
+++ b/core/modules/widgets/widget.js
@@ -189,7 +189,7 @@ Widget.prototype.getVariableInfo = function(name,options) {
 	}
 	return {
 		text: text,
-		resultList: [text]
+		resultList: text === undefined ? text : [text]
 	};
 };
 
@@ -338,7 +338,7 @@ Widget.prototype.makeFakeWidgetWithVariables = function(vars = {}) {
 				const value = vars[name];
 				return Array.isArray(value)
 					? { text: value[0], resultList: value }
-					: { text: value, resultList: [value] };
+					: { text: value, resultList: value === undefined ? value : [value] };
 			}
 			opts = opts || {};
 			opts.variables = Object.assign({}, vars, opts.variables || {});
diff --git a/editions/test/tiddlers/tests/data/transclude/MissingTiddlerAttributeVariable.tid b/editions/test/tiddlers/tests/data/transclude/MissingTiddlerAttributeVariable.tid
new file mode 100644
index 0000000000..eabd1a229c
--- /dev/null
+++ b/editions/test/tiddlers/tests/data/transclude/MissingTiddlerAttributeVariable.tid
@@ -0,0 +1,13 @@
+title: Transclude/MissingTiddlerAttributeVariable
+description: Missing Tiddler Attribute Variable
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+description: hello
+
+<$transclude tiddler=<<nonExistentVariable>> field="description"/>
++
+title: ExpectedResult
+
+<p>hello</p>
\ No newline at end of file