diff --git a/core/modules/utils/errors.js b/core/modules/utils/errors.js
new file mode 100644
index 000000000..fac4b3fa7
--- /dev/null
+++ b/core/modules/utils/errors.js
@@ -0,0 +1,23 @@
+/*\
+title: $:/core/modules/utils/errors.js
+type: application/javascript
+module-type: utils
+
+Custom errors for TiddlyWiki.
+
+\*/
+(function(){
+
+function TranscludeRecursionError() {
+ Error.apply(this,arguments);
+ this.signatures = Object.create(null);
+};
+
+/* Maximum permitted depth of the widget tree for recursion detection */
+TranscludeRecursionError.MAX_WIDGET_TREE_DEPTH = 1000;
+
+TranscludeRecursionError.prototype = Object.create(Error);
+
+exports.TranscludeRecursionError = TranscludeRecursionError;
+
+})();
diff --git a/core/modules/widgets/transclude.js b/core/modules/widgets/transclude.js
index d30ab1fa7..35b4941bd 100755
--- a/core/modules/widgets/transclude.js
+++ b/core/modules/widgets/transclude.js
@@ -30,7 +30,30 @@ TranscludeWidget.prototype.render = function(parent,nextSibling) {
this.parentDomNode = parent;
this.computeAttributes();
this.execute();
- this.renderChildren(parent,nextSibling);
+ try {
+ this.renderChildren(parent,nextSibling);
+ } catch(error) {
+ if(error instanceof $tw.utils.TranscludeRecursionError) {
+ // We were infinite looping.
+ // We need to try and abort as much of the loop as we can, so we will keep "throwing" upward until we find a transclusion that has a different signature.
+ // Hopefully that will land us just outside where the loop began. That's where we want to issue an error.
+ // Rendering widgets beneath this point may result in a freezing browser if they explode exponentially.
+ var transcludeSignature = this.getVariable("transclusion");
+ if(this.getAncestorCount() > $tw.utils.TranscludeRecursionError.MAX_WIDGET_TREE_DEPTH - 50) {
+ // For the first fifty transcludes we climb up, we simply collect signatures.
+ // We're assuming that those first 50 will likely include all transcludes involved in the loop.
+ error.signatures[transcludeSignature] = true;
+ } else if(!error.signatures[transcludeSignature]) {
+ // Now that we're past the first 50, let's look for the first signature that wasn't in the loop. That'll be where we print the error and resume rendering.
+ this.children = [this.makeChildWidget({type: "error", attributes: {
+ "$message": {type: "string", value: $tw.language.getString("Error/RecursiveTransclusion")}
+ }})];
+ this.renderChildren(parent,nextSibling);
+ return;
+ }
+ }
+ throw error;
+ }
};
/*
diff --git a/core/modules/widgets/widget.js b/core/modules/widgets/widget.js
index 69f63a684..cb8e5e881 100755
--- a/core/modules/widgets/widget.js
+++ b/core/modules/widgets/widget.js
@@ -12,9 +12,6 @@ Widget base class
/*global $tw: false */
"use strict";
-/* Maximum permitted depth of the widget tree for recursion detection */
-var MAX_WIDGET_TREE_DEPTH = 1000;
-
/*
Create a widget object for a parse tree node
parseTreeNode: reference to the parse tree node to be rendered
@@ -494,10 +491,8 @@ Widget.prototype.makeChildWidgets = function(parseTreeNodes,options) {
this.children = [];
var self = this;
// Check for too much recursion
- if(this.getAncestorCount() > MAX_WIDGET_TREE_DEPTH) {
- this.children.push(this.makeChildWidget({type: "error", attributes: {
- "$message": {type: "string", value: $tw.language.getString("Error/RecursiveTransclusion")}
- }}));
+ if(this.getAncestorCount() > $tw.utils.TranscludeRecursionError.MAX_WIDGET_TREE_DEPTH) {
+ throw new $tw.utils.TranscludeRecursionError();
} else {
// Create set variable widgets for each variable
$tw.utils.each(options.variables,function(value,name) {
diff --git a/editions/test/tiddlers/tests/data/transclude/Recursion.tid b/editions/test/tiddlers/tests/data/transclude/Recursion.tid
index d75e671eb..b834f3765 100644
--- a/editions/test/tiddlers/tests/data/transclude/Recursion.tid
+++ b/editions/test/tiddlers/tests/data/transclude/Recursion.tid
@@ -7,7 +7,8 @@ title: Output
\whitespace trim
<$transclude $tiddler="Output"/>
+
+
title: ExpectedResult
-Recursive transclusion error in transclude widget
\ No newline at end of file
+Recursive transclusion error in transclude widget
\ No newline at end of file
diff --git a/editions/test/tiddlers/tests/test-widget.js b/editions/test/tiddlers/tests/test-widget.js
index 0d1351f31..1c7665a53 100755
--- a/editions/test/tiddlers/tests/test-widget.js
+++ b/editions/test/tiddlers/tests/test-widget.js
@@ -160,6 +160,47 @@ describe("Widget module", function() {
expect(wrapper.innerHTML).toBe("Recursive transclusion error in transclude widget");
});
+ it("should handle single-tiddler recursion with branching nodes", function() {
+ var wiki = new $tw.Wiki();
+ // Add a tiddler
+ wiki.addTiddlers([
+ {title: "TiddlerOne", text: "<$tiddler tiddler='TiddlerOne'><$transclude /> <$transclude />"},
+ ]);
+ // Test parse tree
+ var parseTreeNode = {type: "widget", children: [
+ {type: "transclude", attributes: {
+ "tiddler": {type: "string", value: "TiddlerOne"}
+ }}
+ ]};
+ // Construct the widget node
+ var widgetNode = createWidgetNode(parseTreeNode,wiki);
+ // Render the widget node to the DOM
+ var wrapper = renderWidgetNode(widgetNode);
+ // Test the rendering
+ expect(wrapper.innerHTML).toBe("Recursive transclusion error in transclude widget Recursive transclusion error in transclude widget");
+ });
+
+ it("should handle many-tiddler recursion with branching nodes", function() {
+ var wiki = new $tw.Wiki();
+ // Add a tiddler
+ wiki.addTiddlers([
+ {title: "TiddlerOne", text: "<$transclude tiddler='TiddlerTwo'/> <$transclude tiddler='TiddlerTwo'/>"},
+ {title: "TiddlerTwo", text: "<$transclude tiddler='TiddlerOne'/>"}
+ ]);
+ // Test parse tree
+ var parseTreeNode = {type: "widget", children: [
+ {type: "transclude", attributes: {
+ "tiddler": {type: "string", value: "TiddlerOne"}
+ }}
+ ]};
+ // Construct the widget node
+ var widgetNode = createWidgetNode(parseTreeNode,wiki);
+ // Render the widget node to the DOM
+ var wrapper = renderWidgetNode(widgetNode);
+ // Test the rendering
+ expect(wrapper.innerHTML).toBe("Recursive transclusion error in transclude widget");
+ });
+
it("should deal with SVG elements", function() {
var wiki = new $tw.Wiki();
// Construct the widget node