Fixes variable enumeration in widgets (#9648)

* fix: variable enumeration in widgets

* fix: fakeWidget should have a variables property

* fix: don't use spread properties

* fix: resolve more embarassing bugs

* chore: tests and whitespace

* fix: simplify opts check

core/modules/filterrunprefixes/cascade.js

@@ -24,7 +24,7 @@ exports.cascade = function(operationSubFunction,options) {
 					}
 					var output = filterFnList[index](options.wiki.makeTiddlerIterator([title]),widget.makeFakeWidgetWithVariables({
 						"currentTiddler": "" + title,
-						"..currentTiddler": widget.getVariable("currentTiddler","")
+						"..currentTiddler": widget.getVariable("currentTiddler",{defaultValue:""})
 					}));
 					if(output.length !== 0) {
 						result = output[0];

core/modules/filterrunprefixes/filter.js

@@ -18,7 +18,7 @@ exports.filter = function(operationSubFunction,options) {
 			results.each(function(title) {
 				var filtered = operationSubFunction(options.wiki.makeTiddlerIterator([title]),widget.makeFakeWidgetWithVariables({
 					"currentTiddler": "" + title,
-					"..currentTiddler": widget.getVariable("currentTiddler",""),
+					"..currentTiddler": widget.getVariable("currentTiddler",{defaultValue:""}),
 					"index": "" + index,
 					"revIndex": "" +  (results.length - 1 - index),
 					"length": "" + results.length

core/modules/filterrunprefixes/map.js

@@ -20,7 +20,7 @@ exports.map = function(operationSubFunction,options) {
 			$tw.utils.each(inputTitles,function(title) {
 				var filtered = operationSubFunction(options.wiki.makeTiddlerIterator([title]),widget.makeFakeWidgetWithVariables({
 					"currentTiddler": "" + title,
-					"..currentTiddler": widget.getVariable("currentTiddler",""),
+					"..currentTiddler": widget.getVariable("currentTiddler",{defaultValue:""}),
 					"index": "" + index,
 					"revIndex": "" +  (inputTitles.length - 1 - index),
 					"length": "" + inputTitles.length

core/modules/filterrunprefixes/reduce.js

@@ -17,7 +17,7 @@ exports.reduce = function(operationSubFunction,options) {
 			results.each(function(title) {
 				var list = operationSubFunction(options.wiki.makeTiddlerIterator([title]),widget.makeFakeWidgetWithVariables({
 					"currentTiddler": "" + title,
-					"..currentTiddler": widget.getVariable("currentTiddler"),
+					"..currentTiddler": widget.getVariable("currentTiddler",{defaultValue:""}),
 					"index": "" + index,
 					"revIndex": "" +  (results.length - 1 - index),
 					"length": "" + results.length,

core/modules/filterrunprefixes/sort.js

@@ -24,7 +24,7 @@ exports.sort = function(operationSubFunction,options) {
 			results.each(function(title) {
 				var key = operationSubFunction(options.wiki.makeTiddlerIterator([title]),widget.makeFakeWidgetWithVariables({
 					"currentTiddler": "" + title,
-					"..currentTiddler": widget.getVariable("currentTiddler")
+					"..currentTiddler": widget.getVariable("currentTiddler",{defaultValue:""})
 				}));
 				sortKeys.push(key[0] || "");
 			});

core/modules/filters/filter.js

@@ -19,7 +19,7 @@ exports.filter = function(source,operator,options) {
 	source(function(tiddler,title) {
 		var list = filterFn.call(options.wiki,options.wiki.makeTiddlerIterator([title]),options.widget.makeFakeWidgetWithVariables({
 			"currentTiddler": "" + title,
-			"..currentTiddler": options.widget.getVariable("currentTiddler","")
+			"..currentTiddler": options.widget.getVariable("currentTiddler",{defaultValue:""})
 		}));
 		if((list.length > 0) === target) {
 			results.push(title);

core/modules/filters/variables.js

@@ -24,4 +24,4 @@ exports.variables = function(source,operator,options) {
 		}
 	}
 	return names.sort();
-};
+};

core/modules/widgets/widget.js

@@ -329,48 +329,43 @@ Widget.prototype.getStateQualifier = function(name) {
 /*
 Make a fake widget with specified variables, suitable for variable lookup in filters. Each variable can be a string or an array of strings
 */
-Widget.prototype.makeFakeWidgetWithVariables = function(variables) {
-	var self = this,
-		variables = variables || {};
-	return {
-		getVariable: function(name,opts) {
-			if($tw.utils.hop(variables,name)) {
-				var value = variables[name];
-				if($tw.utils.isArray(value)) {
-					return value[0];
-				} else {
-					return value;
-				}
-			} else {
-				opts = opts || {};
-				opts.variables = $tw.utils.extend({},variables,opts.variables);
-				return self.getVariable(name,opts);
-			};
+Widget.prototype.makeFakeWidgetWithVariables = function(vars = {}) {
+	const self = this;
+
+	const fakeWidget = {
+		getVariableInfo(name,opts = {}) {
+			if(name in vars) {
+				const value = vars[name];
+				return Array.isArray(value)
+					? { text: value[0], resultList: value }
+					: { text: value, resultList: [value] };
+			}
+			opts = opts || {};
+			opts.variables = Object.assign({}, vars, opts.variables || {});
+			return self.getVariableInfo(name, opts);
 		},
-		getVariableInfo: function(name,opts) {
-			if($tw.utils.hop(variables,name)) {
-				var value = variables[name];
-				if($tw.utils.isArray(value)) {
-					return {
-						text: value[0],
-						resultList: value
-					};
-				} else {
-					return {
-						text: value,
-						resultList: [value]
-					};
-				}
-			} else {
-				opts = opts || {};
-				opts.variables = $tw.utils.extend({},variables,opts.variables);
-				return self.getVariableInfo(name,opts);
-			};
+
+
+		getVariable(name,opts) {
+			return this.getVariableInfo(name, opts).text;
 		},
-		makeFakeWidgetWithVariables: self.makeFakeWidgetWithVariables,
+
 		resolveVariableParameters: self.resolveVariableParameters,
-		wiki: self.wiki
+		wiki: self.wiki,
+		makeFakeWidgetWithVariables: self.makeFakeWidgetWithVariables,
+
+		get variables() {
+			// Merge parent vars via prototype-like delegation
+			return Object.create(self.variables || {}, 
+				Object.keys(vars).reduce((acc, key) => {
+					acc[key] = { value: vars[key], enumerable: true, configurable: true };
+					return acc;
+				}, {})
+			);
+		}
 	};
+
+	return fakeWidget;
 };
 
 /*

editions/test/tiddlers/tests/data/functions/VariableLeakage.tid

@@ -0,0 +1,15 @@
+title: Functions/VariableLeakage
+description: Variables from filter runs or functions should not pollute widget
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\function myvar(element) [<element>]
+\function call(element) [[myvar]is[variable]then<element>]
+
+<<call abc>>
++
+title: ExpectedResult
+
+<p>abc</p>

editions/test/tiddlers/tests/data/functions/VariablesEnumeration.tid

@@ -0,0 +1,14 @@
+title: Functions/VariableEnumeration
+description: Variables should be enumerable within functions
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\function list-vars() [variables[]]
+ 
+<$text text={{{ [function[list-vars]count[]compare:number:gt[0]then[yes]] }}}/>
++
+title: ExpectedResult
+
+<p>yes</p>