add button custom recursion detection and protection

core/language/en-GB/Misc.multids

@@ -37,6 +37,7 @@ Error/NetworkErrorAlert: `<h2>''Network Error''</h2>It looks like the connection
 Error/PutEditConflict: File changed on server
 Error/PutForbidden: Permission denied
 Error/PutUnauthorized: Authentication required
+Error/RecursiveButton: Possible Recursive Error: Button in button is not allowed
 Error/RecursiveTransclusion: Recursive transclusion error in transclude widget
 Error/RetrievingSkinny: Error retrieving skinny tiddler list
 Error/SavingToTWEdit: Error saving to TWEdit

core/modules/widgets/button.js

@@ -18,6 +18,10 @@ var Popup = require("$:/core/modules/utils/dom/popup.js");
 
 var ButtonWidget = function(parseTreeNode,options) {
 	this.initialise(parseTreeNode,options);
+	// Check if any parent is a button. Custom recursion detection for buttons in buttons
+	if(!this.hasVariable("tv-is-button","yes")) {
+		this.setVariable("tv-is-button", "yes");
+	}
 };
 
 /*
@@ -37,6 +41,17 @@ ButtonWidget.prototype.render = function(parent,nextSibling) {
 	// Compute attributes and execute state
 	this.computeAttributes();
 	this.execute();
+	// Check "button in button". Return early with an error message
+	// This check also prevents fatal recursion errors using the transclusion widget
+	if(this.parentWidget && this.parentWidget.hasVariable("tv-is-button","yes")) {
+		var domNode = this.document.createElement("span");
+		var textNode = this.document.createTextNode($tw.language.getString("Error/RecursiveButton"));
+		domNode.appendChild(textNode);
+		domNode.className = "tc-error";
+		parent.insertBefore(domNode,nextSibling);
+		this.domNodes.push(domNode);
+		return;
+	}
 	// Create element
 	if(this.buttonTag && $tw.config.htmlUnsafeElements.indexOf(this.buttonTag) === -1) {
 		tag = this.buttonTag;
@@ -74,7 +89,7 @@ ButtonWidget.prototype.render = function(parent,nextSibling) {
 	if(this["aria-label"]) {
 		domNode.setAttribute("aria-label",this["aria-label"]);
 	}
-	if (this.role) {
+	if(this.role) {
 		domNode.setAttribute("role", this.role);
 	}
 	if(this.popup || this.popupTitle) {

editions/test/tiddlers/tests/data/transclude/Recursion-Button-Transclusion.tid

@@ -0,0 +1,15 @@
+title: Transclude/Recursion/Button
+description: Transclusion recursion inside a button
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+<$button>
+<$transclude/>
+</$button>
++
+title: ExpectedResult
+
+<p><button class=""><span class="tc-error">Possible Recursive Error: Button in button is not allowed</span></button></p>

editions/test/tiddlers/tests/data/transclude/Recursion-Button-in-Button.tid

@@ -0,0 +1,15 @@
+title: Transclude/Recursion/ButtonInButton
+description: Button in Button
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+<$button>Test Button 
+<$button>Invalid button
+</$button>
++
+title: ExpectedResult
+
+<p><button class="">Test Button<span class="tc-error">Possible Recursive Error: Button in button is not allowed</span></button></p>