From a9938a6c671f40de4e5ad70d60149721c37ad7a2 Mon Sep 17 00:00:00 2001
From: "jeremy@jermolene.com" <jeremy@jermolene.com>
Date: Fri, 6 May 2022 15:00:10 +0100
Subject: [PATCH] Improve recursion detection

While retaining backwards compatibility
---
 core/modules/widgets/transclude.js          | 35 +++++++++++++++++----
 editions/test/tiddlers/tests/test-widget.js |  2 +-
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/core/modules/widgets/transclude.js b/core/modules/widgets/transclude.js
index f3122b092..787e6a26d 100755
--- a/core/modules/widgets/transclude.js
+++ b/core/modules/widgets/transclude.js
@@ -48,13 +48,15 @@ TranscludeWidget.prototype.execute = function() {
 	this.sourceType = target.type;
 	this.parseAsInline = target.parseAsInline;
 	// Set context variables for recursion detection
-	var recursionMarker = this.makeRecursionMarker();
+	var recursionMarker = this.makeLegacyRecursionMarker(),
+		newRecursionMarker = this.makeRecursionMarker();
 	if(this.recursionMarker === "yes") {
 		this.setVariable("transclusion",recursionMarker);
+		this.setVariable("$transclusion",newRecursionMarker);
 	}
 	// Check for recursion
 	if(target.parser) {
-		if(this.parentWidget && this.parentWidget.hasVariable("transclusion",recursionMarker)) {
+		if(this.parentWidget && this.parentWidget.hasVariable("$transclusion",newRecursionMarker)) {
 			parseTreeNodes = [{type: "element", tag: "span", attributes: {
 				"class": {type: "string", value: "tc-error"}
 			}, children: [
@@ -273,18 +275,39 @@ TranscludeWidget.prototype.getTransclusionSlotValue = function(name,defaultParse
 };
 
 /*
-Compose a string comprising the title, field and/or index to identify this transclusion for recursion detection
+Compose a string comprising the attributes and variables to identify this transclusion for recursion detection
 */
 TranscludeWidget.prototype.makeRecursionMarker = function() {
-	var attributes = Object.create(null);
+	var marker = {
+		attributes: {},
+		variables: {}
+	}
 	$tw.utils.each(this.attributes,function(value,name) {
-		attributes[name] = value;
+		marker.attributes[name] = value;
 	});
+	for(var name in this.variables) {
+		if(name !== "$transclusion") {
+			marker.variables[name] = this.getVariable(name);
+		}
+	};
+	return JSON.stringify(marker);
+};
+
+/*
+Compose a string comprising the title, field and/or index to identify this transclusion for recursion detection
+*/
+TranscludeWidget.prototype.makeLegacyRecursionMarker = function() {
 	var output = [];
 	output.push("{");
 	output.push(this.getVariable("currentTiddler",{defaultValue: ""}));
 	output.push("|");
-	output.push(JSON.stringify(attributes));
+	output.push(this.transcludeTitle || "");
+	output.push("|");
+	output.push(this.transcludeField || "");
+	output.push("|");
+	output.push(this.transcludeIndex || "");
+	output.push("|");
+	output.push(this.transcludeSubTiddler || "");
 	output.push("}");
 	return output.join("");
 };
diff --git a/editions/test/tiddlers/tests/test-widget.js b/editions/test/tiddlers/tests/test-widget.js
index 8d9c734a0..10c45317e 100755
--- a/editions/test/tiddlers/tests/test-widget.js
+++ b/editions/test/tiddlers/tests/test-widget.js
@@ -157,7 +157,7 @@ describe("Widget module", function() {
 		// Render the widget node to the DOM
 		var wrapper = renderWidgetNode(widgetNode);
 		// Test the rendering
-		expect(wrapper.innerHTML).toBe("<span class=\"tc-error\">Recursive transclusion error in transclude widget</span>\n");
+		expect(wrapper.innerHTML).toBe("<span class=\"tc-error\">Recursive transclusion error in transclude widget</span>\n\n");
 	});
 
 	it("should deal with SVG elements", function() {