feat: added tests

* Skip system tiddlers in back-indexer updates

Fix #9916: editing a system tiddler that links or transcludes another
tiddler made it a backlinks[]/backtranscludes[] source until the next
index rebuild (shipped since v5.3.4).

* Guard BackSubIndexer.update() with isSystemTiddler() on both sides,
  matching the initial scan; this also skips parsing $:/StoryList on
  every navigation
* Add test-back-indexer.js: regression guards plus adversarial probes
  for shadow reveals and hostile __proto__ titles

* Add ChangeNote

bin/build-site.sh

@@ -5,7 +5,7 @@
 # Default to the current version number for building the plugin library
 
 if [  -z "$TW5_BUILD_VERSION" ]; then
-    TW5_BUILD_VERSION=v5.4.1.
+    TW5_BUILD_VERSION=v5.5.0.
 fi
 
 echo "Using TW5_BUILD_VERSION as [$TW5_BUILD_VERSION]"

core-server/server/server.js

@@ -9,15 +9,14 @@ Serve tiddlers over http
 
 "use strict";
 
-let fs, url, path, querystring, crypto, zlib;
+let fs, path, crypto, zlib, URL;
 
 if($tw.node) {
 	fs = require("fs"),
-	url = require("url"),
 	path = require("path"),
-	querystring = require("querystring"),
 	crypto = require("crypto"),
 	zlib = require("zlib");
+	URL = require("url").URL;
 }
 
 /*
@@ -260,8 +259,8 @@ Server.prototype.requestHandler = function(request,response,options) {
 	state.wiki = options.wiki || self.wiki;
 	state.boot = options.boot || self.boot;
 	state.server = self;
-	state.urlInfo = url.parse(request.url);
-	state.queryParameters = querystring.parse(state.urlInfo.query);
+	state.urlInfo = new URL(request.url, "http://localhost");
+	state.queryParameters = Object.fromEntries(state.urlInfo.searchParams);
 	state.pathPrefix = options.pathPrefix || this.get("path-prefix") || "";
 	// Enable CORS
 	if(this.corsEnable) {

core/language/en-GB/ControlPanel.multids

@@ -255,4 +255,5 @@ ViewTemplateTags/Caption: View Template Tags
 ViewTemplateTags/Hint: This rule cascade is used by the default view template to dynamically choose the template for displaying the tags area of a tiddler.
 WikiInformation/Caption: Wiki Information
 WikiInformation/Hint: This page summarises high level information about the configuration of this ~TiddlyWiki. It is designed to enable users to quickly share relevant aspects of the configuration of their ~TiddlyWiki with others, for example when seeking help in one of the forums. No private or personal information is included, and nothing is shared without being explicitly copied and pasted elsewhere
-WikiInformation/Drag/Caption: Drag this link to copy this tool to another wiki
+WikiInformation/Drag/Caption: Drag this link to copy this tool to another wiki
+WikiInformation/Generate/Caption: Click to generate wiki information report

core/modules/filters/listops.js

@@ -9,69 +9,56 @@ Filter operators for manipulating the current selection list
 
 "use strict";
 
+/*
+	Fetch titles from the current list
+*/
+const prepare_results = (source) => {
+	const results = [];
+	source((tiddler,title) => results.push(title));
+	return results;
+};
+
 /*
 Order a list
 */
 exports.order = function(source,operator,options) {
-	var results = [];
-	if(operator.operand.toLowerCase() === "reverse") {
-		source(function(tiddler,title) {
-			results.unshift(title);
-		});
-	} else {
-		source(function(tiddler,title) {
-			results.push(title);
-		});
-	}
-	return results;
+	const results = prepare_results(source);
+	return operator.operand.toLowerCase() === "reverse" ?
+		results.reverse() :
+		results;
 };
 
 /*
 Reverse list
 */
 exports.reverse = function(source,operator,options) {
-	var results = [];
-	source(function(tiddler,title) {
-		results.unshift(title);
-	});
-	return results;
+	return prepare_results(source).reverse();
 };
 
 /*
 First entry/entries in list
 */
 exports.first = function(source,operator,options) {
-	var count = $tw.utils.getInt(operator.operand,1),
-		results = [];
-	source(function(tiddler,title) {
-		results.push(title);
-	});
-	return results.slice(0,count);
+	const count = $tw.utils.getInt(operator.operand,1);
+	return prepare_results(source).slice(0,count);
 };
 
 /*
 Last entry/entries in list
 */
 exports.last = function(source,operator,options) {
-	var count = $tw.utils.getInt(operator.operand,1),
-		results = [];
-	if(count === 0) return results;
-	source(function(tiddler,title) {
-		results.push(title);
-	});
-	return results.slice(-count);
+	const count = $tw.utils.getInt(operator.operand,1);
+	return count === 0 ?
+		[] :
+		prepare_results(source).slice(-count);
 };
 
 /*
 All but the first entry/entries of the list
 */
 exports.rest = function(source,operator,options) {
-	var count = $tw.utils.getInt(operator.operand,1),
-		results = [];
-	source(function(tiddler,title) {
-		results.push(title);
-	});
-	return results.slice(count);
+	const count = $tw.utils.getInt(operator.operand,1);
+	return prepare_results(source).slice(count);
 };
 exports.butfirst = exports.rest;
 exports.bf = exports.rest;
@@ -80,12 +67,9 @@ exports.bf = exports.rest;
 All but the last entry/entries of the list
 */
 exports.butlast = function(source,operator,options) {
-	var count = $tw.utils.getInt(operator.operand,1),
-		results = [];
-	source(function(tiddler,title) {
-		results.push(title);
-	});
-	var index = count === 0 ? results.length : -count;
+	const count = $tw.utils.getInt(operator.operand,1),
+		results = prepare_results(source),
+		index = count === 0 ? results.length : -count;
 	return results.slice(0,index);
 };
 exports.bl = exports.butlast;
@@ -94,22 +78,14 @@ exports.bl = exports.butlast;
 The nth member of the list
 */
 exports.nth = function(source,operator,options) {
-	var count = $tw.utils.getInt(operator.operand,1),
-		results = [];
-	source(function(tiddler,title) {
-		results.push(title);
-	});
-	return results.slice(count - 1,count);
+	const count = $tw.utils.getInt(operator.operand,1);
+	return prepare_results(source).slice(count - 1,count);
 };
 
 /*
 The zero based nth member of the list
 */
 exports.zth = function(source,operator,options) {
-	var count = $tw.utils.getInt(operator.operand,0),
-		results = [];
-	source(function(tiddler,title) {
-		results.push(title);
-	});
-	return results.slice(count,count + 1);
-};
+	const count = $tw.utils.getInt(operator.operand,0);
+	return prepare_results(source).slice(count,count + 1);
+};

core/modules/filters/prefix.js

@@ -13,37 +13,23 @@ Filter operator for checking if a title starts with a prefix
 Export our filter function
 */
 exports.prefix = function(source,operator,options) {
-	var results = [],
-		suffixes = (operator.suffixes || [])[0] || [];
-	if(suffixes.indexOf("caseinsensitive") !== -1) {
-		var operand = operator.operand.toLowerCase();
-		if(operator.prefix === "!") {
-			source(function(tiddler,title) {
-				if(title.toLowerCase().substr(0,operand.length) !== operand) {
-					results.push(title);
-				}
-			});
-		} else {
-			source(function(tiddler,title) {
-				if(title.toLowerCase().substr(0,operand.length) === operand) {
-					results.push(title);
-				}
-			});
+	const results = [],
+		suffixes = (operator.suffixes || [])[0] || [],
+		caseInsensitive = suffixes.indexOf("caseinsensitive") !== -1,
+		negate = operator.prefix === "!";
+
+	const operand = caseInsensitive ?
+		operator.operand.toLowerCase() :
+		operator.operand;
+
+	source((tiddler,title) => {
+		const value = caseInsensitive ? title.toLowerCase() : title;
+		const matches = value.startsWith(operand);
+
+		if(negate ? !matches : matches) {
+			results.push(title);
 		}
-	} else {
-		if(operator.prefix === "!") {
-			source(function(tiddler,title) {
-				if(title.substr(0,operator.operand.length) !== operator.operand) {
-					results.push(title);
-				}
-			});
-		} else {
-			source(function(tiddler,title) {
-				if(title.substr(0,operator.operand.length) === operator.operand) {
-					results.push(title);
-				}
-			});
-		}
-	}
+	});
+
 	return results;
-};
+};

core/modules/filters/tag.js

@@ -22,12 +22,11 @@ exports.tag = function(source,operator,options) {
 		});
 	} else {
 		// Old semantics:
-		var tiddlers;
 		if(operator.prefix === "!") {
 			// Returns a copy of the input if operator.operand is missing
-			tiddlers = options.wiki.getTiddlersWithTag(operator.operand);
+			const excludeTagSet = new Set(options.wiki.getTiddlersWithTag(operator.operand));
 			source(function(tiddler,title) {
-				if(tiddlers.indexOf(title) === -1) {
+				if(!excludeTagSet.has(title)) {
 					results.push(title);
 				}
 			});
@@ -39,9 +38,9 @@ exports.tag = function(source,operator,options) {
 					return indexedResults;
 				}
 			} else {
-				tiddlers = options.wiki.getTiddlersWithTag(operator.operand);
+				const includeTagSet = new Set(options.wiki.getTiddlersWithTag(operator.operand));
 				source(function(tiddler,title) {
-					if(tiddlers.indexOf(title) !== -1) {
+					if(includeTagSet.has(title)) {
 						results.push(title);
 					}
 				});

core/modules/filters/x-listops.js

@@ -11,20 +11,18 @@ Extended filter operators to manipulate the current list.
 
 /*
 	Fetch titles from the current list
-	*/
-var prepare_results = function (source) {
-	var results = [];
-	source(function (tiddler, title) {
-		results.push(title);
-	});
+*/
+const prepare_results = (source) => {
+	const results = [];
+	source((tiddler,title) => results.push(title));
 	return results;
 };
 
 /*
 	Moves a number of items from the tail of the current list before the item named in the operand
-	*/
-exports.putbefore = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.putbefore = function(source,operator) {
+	const results = prepare_results(source),
 		index = results.indexOf(operator.operand),
 		count = $tw.utils.getInt(operator.suffix,1);
 	return (index === -1) ?
@@ -34,9 +32,9 @@ exports.putbefore = function (source, operator) {
 
 /*
 	Moves a number of items from the tail of the current list after the item named in the operand
-	*/
-exports.putafter = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.putafter = function(source,operator) {
+	const results = prepare_results(source),
 		index = results.indexOf(operator.operand),
 		count = $tw.utils.getInt(operator.suffix,1);
 	return (index === -1) ?
@@ -46,9 +44,9 @@ exports.putafter = function (source, operator) {
 
 /*
 	Replaces the item named in the operand with a number of items from the tail of the current list
-	*/
-exports.replace = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.replace = function(source,operator) {
+	const results = prepare_results(source),
 		index = results.indexOf(operator.operand),
 		count = $tw.utils.getInt(operator.suffix,1);
 	return (index === -1) ?
@@ -58,39 +56,39 @@ exports.replace = function (source, operator) {
 
 /*
 	Moves a number of items from the tail of the current list to the head of the list
-	*/
-exports.putfirst = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.putfirst = function(source,operator) {
+	const results = prepare_results(source),
 		count = $tw.utils.getInt(operator.suffix,1);
-	return results.slice(-count).concat(results.slice(0, -count));
+	return [...results.slice(-count), ...results.slice(0, -count)];
 };
 
 /*
 	Moves a number of items from the head of the current list to the tail of the list
-	*/
-exports.putlast = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.putlast = function(source,operator) {
+	const results = prepare_results(source),
 		count = $tw.utils.getInt(operator.suffix,1);
-	return results.slice(count).concat(results.slice(0, count));
+	return [...results.slice(count), ...results.slice(0, count)];
 };
 
 /*
 	Moves the item named in the operand a number of places forward or backward in the list
-	*/
-exports.move = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.move = function(source,operator) {
+	const results = prepare_results(source),
 		index = results.indexOf(operator.operand),
 		count = $tw.utils.getInt(operator.suffix,1),
 		marker = results.splice(index, 1),
-		offset =  (index + count) > 0 ? index + count : 0;
+		offset = (index + count) > 0 ? index + count : 0;
 	return results.slice(0, offset).concat(marker).concat(results.slice(offset));
 };
 
 /*
 	Returns the items from the current list that are after the item named in the operand
-	*/
-exports.allafter = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.allafter = function(source,operator) {
+	const results = prepare_results(source),
 		index = results.indexOf(operator.operand);
 	return (index === -1) ? [] :
 		(operator.suffix) ? results.slice(index) :
@@ -99,9 +97,9 @@ exports.allafter = function (source, operator) {
 
 /*
 	Returns the items from the current list that are before the item named in the operand
-	*/
-exports.allbefore = function (source, operator) {
-	var results = prepare_results(source),
+*/
+exports.allbefore = function(source,operator) {
+	const results = prepare_results(source),
 		index = results.indexOf(operator.operand);
 	return (index === -1) ? [] :
 		(operator.suffix) ? results.slice(0, index + 1) :
@@ -110,9 +108,9 @@ exports.allbefore = function (source, operator) {
 
 /*
 	Appends the items listed in the operand array to the tail of the current list
-	*/
-exports.append = function (source, operator) {
-	var append = $tw.utils.parseStringArray(operator.operand, "true"),
+*/
+exports.append = function(source,operator) {
+	const append = $tw.utils.parseStringArray(operator.operand,"true"),
 		results = prepare_results(source),
 		count = parseInt(operator.suffix) || append.length;
 	return (append.length === 0) ? results :
@@ -122,9 +120,9 @@ exports.append = function (source, operator) {
 
 /*
 	Prepends the items listed in the operand array to the head of the current list
-	*/
-exports.prepend = function (source, operator) {
-	var prepend = $tw.utils.parseStringArray(operator.operand, "true"),
+*/
+exports.prepend = function(source,operator) {
+	const prepend = $tw.utils.parseStringArray(operator.operand,"true"),
 		results = prepare_results(source),
 		count = $tw.utils.getInt(operator.suffix,prepend.length);
 	return (prepend.length === 0) ? results :
@@ -134,21 +132,19 @@ exports.prepend = function (source, operator) {
 
 /*
 	Returns all items from the current list except the items listed in the operand array
-	*/
-exports.remove = function (source, operator) {
-	var array = $tw.utils.parseStringArray(operator.operand, "true"),
-		results = prepare_results(source),
-		count = parseInt(operator.suffix) || array.length,
-		p,
-		len,
-		index;
-	len = array.length - 1;
-	for(p = 0; p < count; ++p) {
-		if(operator.prefix) {
-			index = results.indexOf(array[len - p]);
-		} else {
-			index = results.indexOf(array[p]);
-		}
+*/
+exports.remove = function(source, operator) {
+	const array = $tw.utils.parseStringArray(operator.operand, "true"),
+		results = prepare_results(source);
+
+	if(array.length === 0) {
+		return results;
+	}
+	const count = parseInt(operator.suffix, 10) || array.length,
+		targetItems = operator.prefix ? array.slice(-count).reverse() : array.slice(0, count);
+
+	for(const item of targetItems) {
+		const index = results.indexOf(item);
 		if(index !== -1) {
 			results.splice(index, 1);
 		}
@@ -158,40 +154,32 @@ exports.remove = function (source, operator) {
 
 /*
 	Returns all items from the current list sorted in the order of the items in the operand array
-	*/
-exports.sortby = function (source, operator) {
-	var results = prepare_results(source);
+*/
+exports.sortby = function(source,operator) {
+	const results = prepare_results(source);
 	if(!results || results.length < 2) {
 		return results;
 	}
-	var lookup = $tw.utils.parseStringArray(operator.operand, "true");
-	results.sort(function (a, b) {
-		return lookup.indexOf(a) - lookup.indexOf(b);
-	});
-	return results;
+	const lookup = $tw.utils.parseStringArray(operator.operand,"true");
+	return results.sort((a,b) => lookup.indexOf(a) - lookup.indexOf(b));
 };
 
+
 /*
 	Removes all duplicate items from the current list
-	*/
-exports.unique = function (source, operator) {
-	var results = prepare_results(source);
-	var set = results.reduce(function (a, b) {
-		if(a.indexOf(b) < 0) {
-			a.push(b);
-		}
-		return a;
-	}, []);
-	return set;
+*/
+exports.unique = function(source, operator) {
+	return Array.from(new Set(prepare_results(source)));
 };
 
-var cycleValueInArray = function(results,operands,stepSize) {
-	var resultsIndex,
+const cycleValueInArray = function(results,operands,stepSize) {
+	let resultsIndex,
 		step = stepSize || 1,
 		i = 0,
-		opLength = operands.length,
 		nextOperandIndex;
-	for(i; i < opLength; i++) {
+	const opLength = operands.length;
+
+	for(; i < opLength; i++) {
 		resultsIndex = results.indexOf(operands[i]);
 		if(resultsIndex !== -1) {
 			break;
@@ -213,18 +201,19 @@ var cycleValueInArray = function(results,operands,stepSize) {
 
 /*
 	Toggles an item in the current list.
-	*/
+*/
 exports.toggle = function(source,operator) {
 	return cycleValueInArray(prepare_results(source),operator.operands);
 };
 
 exports.cycle = function(source,operator) {
-	var results = prepare_results(source),
-		operands = (operator.operand.length ? $tw.utils.parseStringArray(operator.operand, "true") : [""]),
-		step = $tw.utils.getInt(operator.operands[1]||"",1);
+	const results = prepare_results(source),
+		operands = operator.operand.length ? $tw.utils.parseStringArray(operator.operand,"true") : [""];
+	let step = $tw.utils.getInt(operator.operands[1] || "",1);
+
 	if(step < 0) {
 		operands.reverse();
 		step = Math.abs(step);
 	}
 	return cycleValueInArray(results,operands,step);
-};
+};

core/modules/indexers/back-indexer.js

@@ -88,10 +88,11 @@ BackSubIndexer.prototype.update = function(updateDescriptor) {
 	var newTargets = [],
 		oldTargets = [],
 		self = this;
-	if(updateDescriptor.old.exists) {
+	// System tiddlers are never indexed as sources, matching the _init() scan
+	if(updateDescriptor.old.exists && !this.wiki.isSystemTiddler(updateDescriptor.old.tiddler.fields.title)) {
 		oldTargets = this._getTarget(updateDescriptor.old.tiddler);
 	}
-	if(updateDescriptor.new.exists) {
+	if(updateDescriptor.new.exists && !this.wiki.isSystemTiddler(updateDescriptor.new.tiddler.fields.title)) {
 		newTargets = this._getTarget(updateDescriptor.new.tiddler);
 	}
 

core/modules/parsers/parseutils.js

@@ -528,67 +528,79 @@ exports.parseAttribute = function(source,pos) {
 		pos = token.end;
 		// Skip whitespace
 		pos = $tw.utils.skipWhiteSpace(source,pos);
-		// Look for a string literal
-		var stringLiteral = $tw.utils.parseStringLiteral(source,pos);
-		if(stringLiteral) {
-			pos = stringLiteral.end;
-			node.type = "string";
-			node.value = stringLiteral.value;
-		} else {
+		do {
+			// Look for a string literal
+			var stringLiteral = $tw.utils.parseStringLiteral(source,pos);
+			if(stringLiteral) {
+				pos = stringLiteral.end;
+				node.type = "string";
+				node.value = stringLiteral.value;
+				break;
+			}
+
 			// Look for a filtered value
 			var filteredValue = $tw.utils.parseTokenRegExp(source,pos,reFilteredValue);
 			if(filteredValue) {
 				pos = filteredValue.end;
 				node.type = "filtered";
 				node.filter = filteredValue.match[1];
-			} else {
-				// Look for an indirect value
-				var indirectValue = $tw.utils.parseTokenRegExp(source,pos,reIndirectValue);
-				if(indirectValue) {
-					pos = indirectValue.end;
-					node.type = "indirect";
-					node.textReference = indirectValue.match[1];
-				} else {
-					// Look for a macro invocation value
-					var macroInvocation = $tw.utils.parseMacroInvocationAsTransclusion(source,pos);
-					if(macroInvocation) {
-						pos = macroInvocation.end;
-						node.type = "macro";
-						node.value = macroInvocation;
-					} else {
-						// Look for an MVV reference value
-						var mvvReference = $tw.utils.parseMVVReferenceAsTransclusion(source,pos);
-						if(mvvReference) {
-							pos = mvvReference.end;
-							node.type = "macro";
-							node.value = mvvReference;
-							node.isMVV = true;
-						} else {
-							var substitutedValue = $tw.utils.parseTokenRegExp(source,pos,reSubstitutedValue);
-							if(substitutedValue) {
-								pos = substitutedValue.end;
-								node.type = "substituted";
-								node.rawValue = substitutedValue.match[1] || substitutedValue.match[2];
-							} else {
-								// Look for a unquoted value
-								var unquotedValue = $tw.utils.parseTokenRegExp(source,pos,reUnquotedAttribute);
-								if(unquotedValue) {
-									pos = unquotedValue.end;
-									node.type = "string";
-									node.value = unquotedValue.match[1];
-								} else if(source.charAt(pos) === "<" && source.charAt(pos + 1) === "<" && source.indexOf(">>",pos) !== -1) {
-									// Value looks like a macro invocation (starts with << with a closing >> ahead) but does not parse as one. Return null so the enclosing tag fails to parse rather than silently binding the attribute to "true" and treating the remainder as further attributes (restores v5.3.8 behaviour)
-									return null;
-								} else {
-									node.type = "string";
-									node.value = "true";
-								}
-							}
-						}
-					}
-				}
+				break;
 			}
-		}
+
+			// Look for an indirect value
+			var indirectValue = $tw.utils.parseTokenRegExp(source,pos,reIndirectValue);
+			if(indirectValue) {
+				pos = indirectValue.end;
+				node.type = "indirect";
+				node.textReference = indirectValue.match[1];
+				break;
+			}
+
+			// Look for a macro invocation value
+			var macroInvocation = $tw.utils.parseMacroInvocationAsTransclusion(source,pos);
+			if(macroInvocation) {
+				pos = macroInvocation.end;
+				node.type = "macro";
+				node.value = macroInvocation;
+				break;
+			}
+
+			// Look for an MVV reference value
+			var mvvReference = $tw.utils.parseMVVReferenceAsTransclusion(source,pos);
+			if(mvvReference) {
+				pos = mvvReference.end;
+				node.type = "macro";
+				node.value = mvvReference;
+				node.isMVV = true;
+				break;
+			}
+
+			// Look for a substituted value
+			var substitutedValue = $tw.utils.parseTokenRegExp(source,pos,reSubstitutedValue);
+			if(substitutedValue) {
+				pos = substitutedValue.end;
+				node.type = "substituted";
+				node.rawValue = substitutedValue.match[1] || substitutedValue.match[2];
+				break;
+			}
+
+			// Look for a unquoted value
+			var unquotedValue = $tw.utils.parseTokenRegExp(source,pos,reUnquotedAttribute);
+			if(unquotedValue) {
+				pos = unquotedValue.end;
+				node.type = "string";
+				node.value = unquotedValue.match[1];
+				break;
+			}
+
+			if(source.charAt(pos) === "<" && source.charAt(pos + 1) === "<" && source.indexOf(">>",pos) !== -1) {
+				// Value looks like a macro invocation (starts with << with a closing >> ahead) but does not parse as one. Return null so the enclosing tag fails to parse rather than silently binding the attribute to "true" and treating the remainder as further attributes (restores v5.3.8 behaviour)
+				return null;
+			}
+
+			node.type = "string";
+			node.value = "true";
+		} while(false);
 	} else {
 		// If there is no equals sign or colon, then this is an attribute with no value, defaulting to "true"
 		node.type = "string";

core/modules/utils/fakedom.js

@@ -115,7 +115,9 @@ var TW_Element = function(tag, namespace) {
 	this.children = [];
 	this._style = {}; // Internal style object
 	this.style = new TW_Style(this); // Proxy for style management
-	this.namespaceURI = namespace || "http://www.w3.org/1999/xhtml";
+	// createElementNS with empty-string or null normalises to null (no namespace) per spec.
+	// https://dom.spec.whatwg.org/#dom-document-createelementns
+	this.namespaceURI = namespace !== undefined ? (namespace || null) : "http://www.w3.org/1999/xhtml";
 };
 
 
@@ -206,7 +208,16 @@ TW_Element.prototype.addEventListener = function(type,listener,useCapture) {
 
 Object.defineProperty(TW_Element.prototype, "tagName", {
 	get: function() {
-		return this.tag || "";
+		if(!this.tag) {
+			return "";
+		}
+		// HTML elements report uppercase tagName per DOM spec. Other namespaces
+		// preserve case. Fakedom only models HTML documents.
+		// https://dom.spec.whatwg.org/#dom-element-tagname
+		if(this.namespaceURI === "http://www.w3.org/1999/xhtml") {
+			return this.tag.toUpperCase();
+		}
+		return this.tag;
 	}
 });
 

core/modules/widgets/diff-text.js

@@ -22,7 +22,7 @@ Inherit from the base widget class
 DiffTextWidget.prototype = new Widget();
 
 DiffTextWidget.prototype.invisibleCharacters = {
-	"\n": "↩︎\n",
+	"\n": "↲\n",
 	"\r": "⇠",
 	"\t": "⇥\t"
 };

core/ui/Actions/new-journal.tid

@@ -4,13 +4,15 @@ description: create a new journal tiddler
 
 \whitespace trim
 \function get-tags() [<textFieldTags>] [<tagsFieldTags>] +[join[ ]]
-<$let journalTitleTemplate={{$:/config/NewJournal/Title}} textFieldTags={{$:/config/NewJournal/Tags}} tagsFieldTags={{$:/config/NewJournal/Tags!!tags}} journalText={{$:/config/NewJournal/Text}}>
-<$wikify name="journalTitle" text="<$transclude $variable='now' format=<<journalTitleTemplate>>/>">
+<$let journalTitle=<<now format={{$:/config/NewJournal/Title}}>>  
+	textFieldTags={{$:/config/NewJournal/Tags}}
+	tagsFieldTags={{$:/config/NewJournal/Tags!!tags}}
+	journalText={{$:/config/NewJournal/Text}}  
+>  
 <$reveal type="nomatch" state=<<journalTitle>> text="">
 <$action-sendmessage $message="tm-new-tiddler" title=<<journalTitle>> tags=<<get-tags>> text={{{ [<journalTitle>get[]] }}}/>
 </$reveal>
 <$reveal type="match" state=<<journalTitle>> text="">
 <$action-sendmessage $message="tm-new-tiddler" title=<<journalTitle>> tags=<<get-tags>> text=<<journalText>>/>
 </$reveal>
-</$wikify>
 </$let>

core/ui/EditTemplate/tags.tid

@@ -6,30 +6,23 @@ tags: $:/tags/EditTemplate
 \procedure lingo-base() $:/language/EditTemplate/
 
 \procedure tag-body-inner(colour,fallbackTarget,colourA,colourB,icon,tagField:"tags")
-<$wikify name="foregroundColor"
-	text="""<$macrocall $name="contrastcolour"
-		target=<<colour>>
-		fallbackTarget=<<fallbackTarget>>
-		colourA=<<colourA>>
-		colourB=<<colourB>>/>
-	"""
->
-	<$let backgroundColor=<<colour>> >
-		<span class="tc-tag-label tc-tag-list-item tc-small-gap-right"
-			data-tag-title=<<currentTiddler>>
-			style=`color:$(foregroundColor)$; fill:$(foregroundColor)$; background-color:$(backgroundColor)$;`
+<$let foregroundColor=<<contrastcolour target=<<colour>> fallbackTarget=<<fallbackTarget>> colourA=<<colourA>> colourB=<<colourB>> >>
+	backgroundColor=<<colour>>  
+>  
+	<span class="tc-tag-label tc-tag-list-item tc-small-gap-right"
+		data-tag-title=<<currentTiddler>>
+		style=`color:$(foregroundColor)$; fill:$(foregroundColor)$; background-color:$(backgroundColor)$;`
+	>
+		<$transclude tiddler=<<icon>>/>
+		<$view field="title" format="text"/>
+		<$button class="tc-btn-invisible tc-remove-tag-button"
+			style.fill=<<foregroundColor>>
 		>
-			<$transclude tiddler=<<icon>>/>
-			<$view field="title" format="text"/>
-			<$button class="tc-btn-invisible tc-remove-tag-button"
-				style.fill=<<foregroundColor>>
-			>
-				<$action-listops $tiddler=<<saveTiddler>> $field=<<tagField>> $subfilter="-[{!!title}]"/>
-				{{$:/core/images/close-button}}
-			</$button>
-		</span>
-	</$let>
-</$wikify>
+			<$action-listops $tiddler=<<saveTiddler>> $field=<<tagField>> $subfilter="-[{!!title}]"/>
+			{{$:/core/images/close-button}}
+		</$button>
+	</span>
+</$let>
 \end
 
 \procedure tag-body(colour,palette,icon,tagField:"tags")

core/ui/TagPickerTagTemplate.tid

@@ -16,15 +16,13 @@ title: $:/core/ui/TagPickerTagTemplate
 	<$set name="backgroundColor"
 		value={{{ [<currentTiddler>] :cascade[all[shadows+tiddlers]tag[$:/tags/TiddlerColourFilter]!is[draft]get[text]] }}}
 	>
-		<$wikify name="foregroundColor"
-			text="""<$macrocall $name="contrastcolour" target=<<backgroundColor>> fallbackTarget=<<fallbackTarget>> colourA=<<colourA>> colourB=<<colourB>>/>"""
-		>
+		<$let foregroundColor=<<contrastcolour target=<<backgroundColor>> fallbackTarget=<<fallbackTarget>> colourA=<<colourA>> colourB=<<colourB>> >> >
 			<span class="tc-tag-label tc-btn-invisible"
 				style=<<tag-pill-styles>>
 				data-tag-title=<<currentTiddler>>
 			>
 				{{||$:/core/ui/TiddlerIcon}}<$view field="title" format="text"/>
 			</span>
-		</$wikify>
+		</$let>
 	</$set>
 </$button>

core/ui/ViewToolbar/new-journal-here.tid

@@ -6,7 +6,6 @@ description: {{$:/language/Buttons/NewJournalHere/Hint}}
 \whitespace trim
 \procedure journalButton()
 <$button tooltip={{$:/language/Buttons/NewJournalHere/Hint}} aria-label={{$:/language/Buttons/NewJournalHere/Caption}} class=<<tv-config-toolbar-class>>>
-<$wikify name="journalTitle" text="""<$transclude $variable="now" format=<<journalTitleTemplate>>/>""">
 <$action-sendmessage $message="tm-new-tiddler" title=<<journalTitle>> tags=`[[$(currentTiddlerTag)$]] $(journalTags)$`/>
 <%if [<tv-config-toolbar-icons>match[yes]] %>
 {{$:/core/images/new-journal-button}}
@@ -16,9 +15,11 @@ description: {{$:/language/Buttons/NewJournalHere/Hint}}
 <$text text={{$:/language/Buttons/NewJournalHere/Caption}}/>
 </span>
 <%endif%>
-</$wikify>
 </$button>
 \end
-<$let journalTitleTemplate={{$:/config/NewJournal/Title}} journalTags={{$:/config/NewJournal/Tags}} currentTiddlerTag=<<currentTiddler>>>
+<$let journalTitle=<<now format={{$:/config/NewJournal/Title}}>>
+	journalTags={{$:/config/NewJournal/Tags}}
+	currentTiddlerTag=<<currentTiddler>>  
+>
 <<journalButton>>
 </$let>

core/ui/WikiInformation.tid

@@ -17,6 +17,10 @@ This page summarises high level information about the configuration of this ~Tid
 Drag this link to copy this tool to another wiki
 \end intrinsic-lingo-Drag/Caption
 
+\procedure intrinsic-lingo-Generate/Caption()
+Click to generate wiki information report
+\end intrinsic-lingo-Generate/Caption
+
 \procedure lingo(title,mode:"inline")
 <%if [<title>addprefix<lingo-base>is[shadow]] %>
 	<$transclude $tiddler={{{ [<title>addprefix<lingo-base>] }}} $mode=<<mode>>/>
@@ -105,7 +109,7 @@ Drag this link to copy this tool to another wiki
 
 <$button>
 <<display-wiki-info-modal>>
-Click to generate wiki information report
+<<lingo title:"Generate/Caption">>
 </$button>
 
 <$link to="$:/core/ui/ControlPanel/WikiInformation">

core/wiki/config/OfficialPluginLibrary.tid

@@ -1,6 +1,6 @@
 title: $:/config/OfficialPluginLibrary
 tags: $:/tags/PluginLibrary
-url: https://tiddlywiki.com/library/v5.4.1/index.html
+url: https://tiddlywiki.com/library/v5.5.0/index.html
 caption: {{$:/language/OfficialPluginLibrary}}
 
 {{$:/language/OfficialPluginLibrary/Hint}}

editions/dev/tiddlers/build/Releasing a new version of TiddlyWiki.tid

@@ -8,9 +8,8 @@ type: text/vnd.tiddlywiki
 # Ensure the new release banner image is up to date
 # Update ''master'' with changes from ''tiddlywiki-com''
 # Verify the version numbers in [[$:/config/OfficialPluginLibrary]] in `core/wiki/config/OfficialPluginLibrary.tid`
-# Move the latest release note from the prerelease edition into the tw5.com edition
-# Adjust the release date and the ''released'' field of the latest release tiddler (eg, [[Release 5.1.3]])
-# Also adjust the github.com comparison link to point to the tag for the new release
+# Adjust the release date and the ''released'' field of the release tiddler (eg, [[Release 5.1.3]])
+# Update the ''release-introduction'' definition with the new release text, and if necessary the ''description'' field of the release tiddler
 # Adjust the tiddler [[TiddlyWiki Archive]] to include the new version number
 # Ensure [[TiddlyWiki Releases]] has the new version as the default tab
 # Adjust the modified time of HelloThere
@@ -23,7 +22,6 @@ type: text/vnd.tiddlywiki
 # Run `./bin/readme-bld.sh` to build the readme files
 # Commit the new readme files to ''master''
 # Restore `package.json` to the previous version number
-# Adjust the link for "GitHub for detailed change history of this release" in the release note
 # Add the credits for the new release banner to the release note, including a link to the GitHub instance of the image from the commit history
 
 !! Make New Release

editions/prerelease/tiddlers/system/PrereleaseLocalPluginLibrary.tid

@@ -1,6 +1,6 @@
 title: $:/config/LocalPluginLibrary
 tags: $:/tags/PluginLibrary
-url: http://127.0.0.1:8080/prerelease/library/v5.4.1/index.html
+url: http://127.0.0.1:8080/prerelease/library/v5.5.0/index.html
 caption: {{$:/language/OfficialPluginLibrary}} (Prerelease Local)
 
 A locally installed version of the official ~TiddlyWiki plugin library at tiddlywiki.com for testing and debugging. //Requires a local web server to share the library//

editions/prerelease/tiddlers/system/PrereleaseOfficialPluginLibrary.tid

@@ -1,6 +1,6 @@
 title: $:/config/OfficialPluginLibrary
 tags: $:/tags/PluginLibrary
-url: https://tiddlywiki.com/prerelease/library/v5.4.1/index.html
+url: https://tiddlywiki.com/prerelease/library/v5.5.0/index.html
 caption: {{$:/language/OfficialPluginLibrary}} (Prerelease)
 
 The prerelease version of the official ~TiddlyWiki plugin library at tiddlywiki.com. Plugins, themes and language packs are maintained by the core team.

editions/prerelease/tiddlers/system/TiddlyWiki Pre-release Size Comparison.tid

@@ -0,0 +1,94 @@
+created: 20260714055110474
+modified: 20260714055129225
+tags: 
+title: TiddlyWiki Pre-release Size Comparison
+
+
+\function bytes.to.mib(size) [abs[]divide[1048576]fixed[2]addsuffix[ MiB]]
+\function bytes.to.kib(size) [abs[]divide[1024]fixed[2]addsuffix[ KiB]]
+\function format.file.size(size) [<size>abs[]compare:number:gteq[1048576]bytes.to.mib<size>] :else[<size>abs[]compare:number:gteq[1024]bytes.to.kib<size>] :else[<size>addsuffix[ bytes]]
+
+
+\procedure get-wiki-filesize(filepath)
+	\procedure completion-get-json()
+			<!-- Success -->
+			<$list filter="[<status>compare:number:gteq[200]compare:number:lteq[299]]" variable="ignore">
+				<$action-log msg="completed" size={{{ [<data>jsonget[size]] }}}/>
+				<$action-setfield $tiddler=`$:/temp/file-size-comparison/$(filepath)$` text={{{ [<data>jsonget[size]] }}} />
+			</$list>
+	\end completion-get-json
+	
+	<$action-sendmessage
+		$message="tm-http-request"
+		url=`https://api.github.com/repos/TiddlyWiki/tiddlywiki.com-gh-pages/contents/$(filepath)$?ref=master`
+		method="GET"
+		oncompletion=<<completion-get-json>>
+		var-filepath=<<filepath>>
+		/>
+\end get-wiki-filesize
+
+\procedure get-wiki-filesizes()
+<$list filter="empty.html prerelease/empty.html" variable="filepath">
+	<$action-log />
+	<<$transclude $variable="get-wiki-filesize" filepath=<<filepath>> >>
+
+</$list>
+\end get-wiki-filesizes
+
+
+<%if [[$:/temp/file-size-comparison/empty.html]is[tiddler]] [[$:/temp/file-size-comparison/prerelease/empty.html]is[tiddler]] :and[count[]match[2]]%>
+<$let delta={{{ [{$:/temp/file-size-comparison/empty.html}subtract{$:/temp/file-size-comparison/prerelease/empty.html}] }}}
+message={{{ [<delta>sign[]match[-1]then[Size increased]] :else[<delta>sign[]match[1]then[Size decreased]] :else[[Size has not changed]]  }}}
+>
+
+<svg xmlns="http://www.w3.org/2000/svg" width="158" height="20" role="img" style.zoom="1.5" aria-label="<$text text=<<message>>/>: <$text text={{{ [format.file.size<delta>] }}} /> bytes">
+  <title><$text text=<<message>>/>: <$text text={{{ [format.file.size<delta>] }}} /></title>
+  <filter id="blur">
+    <feGaussianBlur stdDeviation="16"/>
+  </filter>
+  <linearGradient id="s" x2="0" y2="100%">
+    <stop offset="0" stop-color="#bbb" stop-opacity=".1"/>
+    <stop offset="1" stop-opacity=".1"/>
+  </linearGradient>
+  <clipPath id="r">
+    <rect width="158" height="20" rx="3"/>
+  </clipPath>
+  <g clip-path="url(#r)">
+    <rect width="93" height="20" fill="#555"/>
+    <rect x="93" width="65" height="20" fill="#67ac09"/>
+    <rect width="158" height="20" fill="url(#s)"/>
+  </g>
+  <g fill="#fff" text-anchor="middle" font-family="Verdana,Geneva,DejaVu Sans,sans-serif" text-rendering="geometricPrecision" font-size="110">
+    <g transform="scale(.1)">
+      <g aria-hidden="true" fill="#010101">
+        <text x="475" y="150" fill-opacity=".8" filter="url(#blur)" textLength="830"><$text text=<<message>>/></text>
+        <text x="475" y="150" fill-opacity=".3" textLength="830"><$text text=<<message>>/></text>
+      </g>
+      <text x="475" y="140" textLength="830"><$text text=<<message>>/></text>
+    </g>
+    <g transform="scale(.1)">
+      <g aria-hidden="true" fill="#010101">
+        <text x="1245" y="150" fill-opacity=".8" filter="url(#blur)" textLength="550"><$text text={{{ [format.file.size<delta>] }}} /></text>
+        <text x="1245" y="150" fill-opacity=".3" textLength="550"><$text text={{{ [format.file.size<delta>] }}} /></text>
+      </g>
+      <text x="1245" y="140" textLength="550"><$text text={{{ [format.file.size<delta>] }}} /></text>
+    </g>
+  </g>
+</svg>
+
+; Pre-release empty.html
+: <$text text={{{ [{$:/temp/file-size-comparison/prerelease/empty.html}] }}} /> bytes
+; <$text text={{{ [tag[ReleaseNotes]sort[released]last[]] }}} /> empty.html
+: <$text text={{{ [{$:/temp/file-size-comparison/empty.html}] }}} /> bytes
+
+---
+
+</$let>
+<%else %>
+<$button actions=<<get-wiki-filesizes>> class="tc-btn-big-green">
+Compare size of empty.html
+</$button>
+<%endif%>
+
+
+

editions/prerelease/tiddlers/system/TiddlyWiki Pre-release.tid

@@ -13,6 +13,8 @@ The pre-release is also available as an [[empty wiki|https://tiddlywiki.com/prer
 
 </div>
 
+{{ TiddlyWiki Pre-release Size Comparison }}
+
 <$list filter="[tag[ReleaseNotes]!has[released]!sort[created]]">
 <div class="tc-titlebar">
 <h2 class="tc-title"><$text text=<<currentTiddler>>/></h2>

editions/test/tiddlers/tests/data/filters/listops.tid

@@ -0,0 +1,14 @@
+title: Filters/ListOps
+description: Test listops operators
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+(<$text text={{{ =[[E]] =[[A]] =[[B]] =[[C]] =[[C]] =[[D]] =[[C]] +[unique[]join[]] }}}/>)
+
++
+title: ExpectedResult
+
+<p>(EABCD)</p>

editions/test/tiddlers/tests/test-back-indexer.js

@@ -0,0 +1,162 @@
+/*\
+title: test-back-indexer.js
+type: application/javascript
+tags: [[$:/tags/test-spec]]
+
+Regression tests for #9916: the back-indexer must never record system
+tiddlers as backlink or backtransclude sources, neither when the index is
+first built nor when it is incrementally updated.
+
+\*/
+"use strict";
+
+describe("Back-indexer system source tests (#9916)", function() {
+	function setupWiki() {
+		// Create a wiki with indexers and one primed backlink pair
+		var wiki = new $tw.Wiki();
+		wiki.addIndexersToWiki();
+
+		wiki.addTiddler({
+			title: "TestIncoming",
+			text: ""});
+
+		wiki.addTiddler({
+			title: "TestOutgoing",
+			text: "A link to [[TestIncoming]]"});
+		return wiki;
+	}
+
+	it("should never report a system tiddler as a backlink source", function() {
+		// Browser console: $tw.wiki.filterTiddlers("[[HelloThere]backlinks[]]") to prime the index,
+		// then $tw.wiki.addTiddler(new $tw.Tiddler({title: "$:/temp/demo", text: "[[HelloThere]]"}))
+		// and run the filter again; $:/temp/demo must not appear.
+		var wiki = setupWiki();
+		// The first lookup builds the lazy index; its initial scan skips system tiddlers
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		// The incremental update() must skip them too
+		wiki.addTiddler({
+			title: "$:/temp/system-source",
+			text: "A link to [[TestIncoming]]"});
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+	});
+
+	it("should keep backlinks stable while a linking system tiddler is modified and deleted", function() {
+		// Browser console: $tw.wiki.filterTiddlers("[[HelloThere]backlinks[]]") to prime the index,
+		// then $tw.wiki.addTiddler(new $tw.Tiddler({title: "$:/temp/demo", text: "[[HelloThere]]"})),
+		// change its text, $tw.wiki.deleteTiddler("$:/temp/demo"); the filter result never changes.
+		var wiki = setupWiki();
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		wiki.addTiddler({
+			title: "$:/temp/system-source",
+			text: "A link to [[TestIncoming]]"});
+		// Modify: both the old and the new side of the index update are system tiddlers
+		wiki.addTiddler({
+			title: "$:/temp/system-source",
+			text: "Links to [[TestIncoming]] and [[TestOutgoing]]"});
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		wiki.deleteTiddler("$:/temp/system-source");
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+	});
+
+	it("should drop the backlink when its source is renamed to a system title", function() {
+		// Browser console: $tw.wiki.addTiddler(new $tw.Tiddler({title: "Demo", text: "[[HelloThere]]"})),
+		// confirm Demo is in $tw.wiki.filterTiddlers("[[HelloThere]backlinks[]]"), then
+		// $tw.wiki.renameTiddler("Demo","$:/Demo"); neither Demo nor $:/Demo remains a source.
+		var wiki = setupWiki();
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		wiki.renameTiddler("TestOutgoing","$:/TestOutgoing");
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("");
+	});
+
+	it("should gain the backlink when a linking system tiddler is renamed to a normal title", function() {
+		// Browser console: $tw.wiki.addTiddler(new $tw.Tiddler({title: "$:/temp/demo", text: "[[HelloThere]]"})),
+		// then $tw.wiki.renameTiddler("$:/temp/demo","DemoVisible");
+		// DemoVisible now appears in $tw.wiki.filterTiddlers("[[HelloThere]backlinks[]]").
+		var wiki = setupWiki();
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		wiki.addTiddler({
+			title: "$:/temp/system-source",
+			text: "A link to [[TestIncoming]]"});
+		wiki.renameTiddler("$:/temp/system-source","VisibleSource");
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing,VisibleSource");
+	});
+
+	it("should still report normal sources for a system tiddler target", function() {
+		// Only sources are filtered, targets are not. Browser console:
+		// $tw.wiki.addTiddler(new $tw.Tiddler({title: "Demo", text: "[[$:/config/NewJournal/Tags]]"}));
+		// $tw.wiki.filterTiddlers("[[$:/config/NewJournal/Tags]backlinks[]]") contains Demo.
+		var wiki = setupWiki();
+		expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		wiki.addTiddler({
+			title: "TestSystemLinker",
+			text: "A link to [[$:/config/Target]]"});
+		expect(wiki.filterTiddlers("[[$:/config/Target]backlinks[]]").join(",")).toBe("TestSystemLinker");
+	});
+
+	describe("Adversarial probes", function() {
+		it("should never index a shadow tiddler as a source, even when revealed by deleting its override", function() {
+			// Goes red when a refactor of BackSubIndexer.update() checks the tiddler instead of
+			// the exists flag:
+			//	if(updateDescriptor["new"].tiddler) { ... } // broken: goes red here
+			//	if(updateDescriptor["new"].exists) { ... } // correct: stays green
+			// After deleteTiddler() on an override, boot.js fills new.tiddler via getTiddler(),
+			// which falls back to the revealed shadow, while new.exists stays false because
+			// only the real store counts. The broken variant indexes the shadow's links and
+			// the final expect fails with "TestOutgoing,ShadowSource".
+			// The first expect also goes red if _init() ever starts scanning shadows; the
+			// middle expect pins that a real override IS indexed, so this probe cannot be
+			// satisfied by indexing nothing at all.
+			// Browser console: override a plugin shadow with text [[HelloThere]], check it appears in
+			// $tw.wiki.filterTiddlers("[[HelloThere]backlinks[]]"), then $tw.wiki.deleteTiddler(title);
+			// the title disappears from the filter result even though the shadow still renders.
+			var wiki = setupWiki();
+			wiki.addTiddler({
+				title: "$:/plugins/test/shadow-plugin",
+				type: "application/json",
+				"plugin-type": "plugin",
+				text: JSON.stringify({tiddlers: {
+					"ShadowSource": {title: "ShadowSource", text: "A shadow link to [[TestIncoming]]"}
+				}})});
+			wiki.readPluginInfo();
+			wiki.registerPluginTiddlers("plugin");
+			wiki.unpackPluginTiddlers();
+			// The initial scan sees only real tiddlers, not the shadow
+			expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+			wiki.addTiddler({
+				title: "ShadowSource",
+				text: "An overriding link to [[TestIncoming]]"});
+			expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing,ShadowSource");
+			// Deleting the override reveals the shadow; it must not enter the index
+			wiki.deleteTiddler("ShadowSource");
+			expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+		});
+
+		it("should handle hostile titles like __proto__ as source and target", function() {
+			// Goes red when any title-keyed hashmap on the backlinks path is created like this:
+			//	this.index = {}; // broken: goes red here
+			// instead of:
+			//	this.index = Object.create(null); // correct: stays green
+			//	this.index = new Map(); // a Map/Set refactor also stays green
+			// The same applies to the boot tiddler store and to the per-target source maps
+			// (self.index[target] = ...). On a plain {} the assignment index["__proto__"] = x
+			// stores no key; it silently replaces the object's prototype. Depending on which
+			// map regresses, the __proto__ tiddler never registers as a source (second expect),
+			// or its target entry lands in the shared prototype, where it pollutes every other
+			// lookup and lookup("__proto__") returns garbage (third expect).
+			// Browser console: $tw.wiki.addTiddler(new $tw.Tiddler({title: "__proto__",
+			// text: "[[HelloThere]]"})); __proto__ appears in
+			// $tw.wiki.filterTiddlers("[[HelloThere]backlinks[]]") and
+			// $tw.wiki.filterTiddlers("[[__proto__]backlinks[]]") lists tiddlers linking to it.
+			var wiki = setupWiki();
+			expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing");
+			wiki.addTiddler({
+				title: "__proto__",
+				text: "A link to [[TestIncoming]]"});
+			expect(wiki.filterTiddlers("TestIncoming +[backlinks[]]").join(",")).toBe("TestOutgoing,__proto__");
+			wiki.addTiddler({
+				title: "ProtoLinker",
+				text: "A link to [[__proto__]]"});
+			expect(wiki.filterTiddlers("[[__proto__]backlinks[]]").join(",")).toBe("ProtoLinker");
+		});
+	});
+});

editions/test/tiddlers/tests/test-fakedom.js

@@ -19,6 +19,56 @@ describe("fakedom tests", function() {
 		expect($tw.fakeDocument.createTextNode("text").TEXT_NODE).toBe(3);
 	});
 
+	// Per DOM spec, tagName returns the HTML-uppercased qualified name for HTML
+	// elements. Other namespaces preserve case.
+	// https://dom.spec.whatwg.org/#dom-element-tagname
+	var HTML_NS = "http://www.w3.org/1999/xhtml";
+	var SVG_NS = "http://www.w3.org/2000/svg";
+
+	it("tagName uppercases for HTML namespace", function() {
+		// Default namespace is HTML
+		expect($tw.fakeDocument.createElement("div").tagName).toBe("DIV");
+		// The exact predicate the select widget relies on (#9839)
+		expect($tw.fakeDocument.createElement("optgroup").tagName === "OPTGROUP").toBe(true);
+		// Already-uppercase input stays uppercase
+		expect($tw.fakeDocument.createElement("OPTGROUP").tagName).toBe("OPTGROUP");
+		// Mixed-case input is normalised
+		expect($tw.fakeDocument.createElement("Div").tagName).toBe("DIV");
+		// Hyphenated custom-element names uppercase whole tag, hyphens survive
+		expect($tw.fakeDocument.createElement("my-button").tagName).toBe("MY-BUTTON");
+		// Empty tag returns empty string
+		expect($tw.fakeDocument.createElement("").tagName).toBe("");
+		// Explicit HTML namespace via createElementNS uppercases the same way
+		expect($tw.fakeDocument.createElementNS(HTML_NS,"Div").tagName).toBe("DIV");
+	});
+
+	it("tagName preserves case for non-HTML namespaces", function() {
+		// SVG: lowercase preserved
+		expect($tw.fakeDocument.createElementNS(SVG_NS,"circle").tagName).toBe("circle");
+		// SVG: camelCase preserved (linearGradient is the canonical example)
+		expect($tw.fakeDocument.createElementNS(SVG_NS,"linearGradient").tagName).toBe("linearGradient");
+		// SVG: already-uppercase input is also preserved (NOT lowercased)
+		expect($tw.fakeDocument.createElementNS(SVG_NS,"DIV").tagName).toBe("DIV");
+		// Empty namespace string is "no namespace", not HTML. Case preserved.
+		expect($tw.fakeDocument.createElementNS("","div").tagName).toBe("div");
+	});
+
+	it("tagName reflects current state without mutating it", function() {
+		// Reading tagName must not overwrite the internal `tag` field
+		var el = $tw.fakeDocument.createElement("div");
+		expect(el.tagName).toBe("DIV");
+		expect(el.tag).toBe("div");
+		// Idempotent: two reads return identical values
+		var first = el.tagName, second = el.tagName;
+		expect(first).toBe(second);
+		// Dynamic namespace change is reflected. The getter must read current
+		// state, not a value cached at construction time.
+		var dynamic = $tw.fakeDocument.createElement("foo");
+		expect(dynamic.tagName).toBe("FOO");
+		dynamic.namespaceURI = SVG_NS;
+		expect(dynamic.tagName).toBe("foo");
+	});
+
 	// Real CSSStyleDeclaration returns undefined for Symbol property keys.
 	// Without a guard, the TW_Style Proxy throws on Symbol access. This bites
 	// in practice when Jasmine pretty-prints fakedom elements on failure.

editions/tw5.com/tiddlers/releasenotes/5.4.0/#9715.tid

@@ -0,0 +1,8 @@
+title: $:/changenotes/5.4.0/#9715
+change-type: performance
+change-category: filters
+tags: $:/tags/ChangeNote
+github-contributors: linonetwo
+release: 5.4.0
+description: Optimized tag[] and !tag[] filter operators to use Set for O(1) lookup, matching search:tags[] performance.
+github-links: [[https://github.com/Jermolene/TiddlyWiki5/pull/9715]]

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9736-difftext-newline-glyph.tid

@@ -0,0 +1,12 @@
+change-category: widget
+change-type: enhancement
+created: 20260711020921000
+description: The diff-text widget shows removed or added newlines with a visible ↲ glyph
+github-contributors: pmario
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9736
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#9736
+type: text/vnd.tiddlywiki
+
+* The diff-text widget marks newline characters in a diff with the visible `↲` glyph (U+21B2) instead of an invisible character, so line break changes are recognisable in the rendered diff (fixes [[Issue #9461|https://github.com/TiddlyWiki/TiddlyWiki5/issues/9461]])

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9737-wiki-info-translatable.tid

@@ -0,0 +1,12 @@
+change-category: translation
+change-type: enhancement
+created: 20260711020729000
+description: The "Click to generate wiki info" button in the control panel is now translatable
+github-contributors: pmario
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9737
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#9737
+type: text/vnd.tiddlywiki
+
+* The "Click to generate wiki info" button on the control panel's wiki information tab uses a language string instead of hard coded English text, so translators can localise it (fixes [[Issue #9654|https://github.com/TiddlyWiki/TiddlyWiki5/issues/9654]])

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9742-node-dep0169-warning.tid

@@ -0,0 +1,12 @@
+change-category: nodejs
+change-type: bugfix
+created: 20260711020057000
+description: The Node.js server no longer emits the DEP0169 url.parse() deprecation warning
+github-contributors: pmario
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9742
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#9742
+type: text/vnd.tiddlywiki
+
+* The server module parses request URLs with the WHATWG `URL` API instead of the deprecated `url.parse()`, so recent Node.js versions no longer print the DEP0169 deprecation warning on startup (fixes [[Issue #9628|https://github.com/TiddlyWiki/TiddlyWiki5/issues/9628]])

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9816.tid

@@ -0,0 +1,10 @@
+ title: $:/changenotes/5.5.0/#9816
+description: Replaces some wikify widget with call dynamic syntax
+release: 5.5.0
+tags: $:/tags/ChangeNote
+change-type: enhancement
+change-category: internal
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9816
+github-contributors: Leilei332
+
+Replaces unnecessary wikify widget usage with call dynamic attribute syntax.

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9843-fakedom-tagname-spec.tid

@@ -0,0 +1,13 @@
+change-category: internal
+change-type: bugfix
+created: 20260711014241000
+description: fakedom tagName is uppercase for HTML elements, matching the DOM spec
+github-contributors: pmario
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/9843
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#9843
+type: text/vnd.tiddlywiki
+
+* `$tw.fakeDocument` elements now report `tagName` in uppercase for HTML elements, matching the DOM specification and real browsers; code that compares fakedom `tagName` against lowercase strings must be updated
+* Creating an element with an empty or null namespace now produces a plain element without a namespace

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9917-back-indexer-system-tiddler-sources.tid

@@ -0,0 +1,12 @@
+change-category: filters
+change-type: bugfix
+created: 20260711011920000
+description: backlinks[] and backtranscludes[] no longer report edited system tiddlers as sources
+github-contributors: pmario
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/issues/9917
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#9917
+type: text/vnd.tiddlywiki
+
+* Editing a system tiddler that links or transcludes another tiddler no longer adds it as a [[backlinks|backlinks Operator]] or [[backtranscludes|backtranscludes Operator]] source; the incremental back-index update now skips system tiddlers like the initial scan always did

editions/tw5.com/tiddlers/releasenotes/5.5.0/#9942-optimize-listops.tid

@@ -0,0 +1,13 @@
+change-category: filters
+change-type: enhancement
+created: 20260726124618748
+description: Optimizes listops filter operators
+github-contributors: saqimtiaz
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/issues/9942
+modified: 20260726125232992
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#9942
+type: text/vnd.tiddlywiki
+
+* The listops filter operators have been rewritten using more modern JavaScript (ES2017). The `unique` and `remove` operators have improved performance in certain circumstances.

editions/tw5.com/tiddlers/releasenotes/5.5.0/Release 5.5.0.tid

@@ -0,0 +1,13 @@
+caption: 5.5.0
+created: 20260710103826404
+modified: 20260710103826404
+tags: ReleaseNotes
+title: Release 5.5.0
+type: text/vnd.tiddlywiki
+description: Under development
+
+\procedure release-introduction()
+Release v5.5.0 is under development.
+\end release-introduction
+
+<<releasenote 5.5.0>>

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "tiddlywiki",
-  "version": "5.4.1",
+  "version": "5.5.0-prerelease",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
@@ -19,7 +19,7 @@
         "globals": "16.4.0"
       },
       "engines": {
-        "node": ">=0.8.2"
+        "node": ">=20.0.0"
       }
     },
     "node_modules/@eslint-community/eslint-utils": {
@@ -717,10 +717,20 @@
       "license": "ISC"
     },
     "node_modules/js-yaml": {
-      "version": "4.1.1",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.1.tgz",
-      "integrity": "sha512-qQKT4zQxXl8lLwBtHMWwaTcGfFOZviOJet3Oy/xmGk2gZH677CJM9EvtfdSkgWcATZhj/55JZ0rmy3myCT5lsA==",
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.3.0.tgz",
+      "integrity": "sha512-1td788aAnnZ5qs7V2QIRl1owjtYpbKt749Y3xauqQgwIIGF/xXWz1wMTEBx5O3LK3lXLVuqXPdPxj2BoFHaW9Q==",
       "dev": true,
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/puzrin"
+        },
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/nodeca"
+        }
+      ],
       "license": "MIT",
       "dependencies": {
         "argparse": "^2.0.1"

package.json

@@ -1,7 +1,7 @@
 {
   "name": "tiddlywiki",
   "preferGlobal": true,
-  "version": "5.4.1",
+  "version": "5.5.0-prerelease",
   "author": "Jeremy Ruston <jeremy@jermolene.com>",
   "description": "a non-linear personal web notebook",
   "contributors": [