[BUG] Any usage of an undefined function in a filter triggers a red Internal JavaScript Error popup

[saqimtiaz]

Describe the bug

This code will trigger the error in v5.3.0 pre-release:

{{{ [doesnot.exist[]] }}}

The description is: Uncaught Linked List only accepts string values, not undefined.

[saqimtiaz]

TiddlyWiki5/core/modules/filters/unknown.js

Lines 29 to 31 in 6bb0da0

	var variableInfo = options.widget && options.widget.getVariableInfo && options.widget.getVariableInfo(operator.operator,{params: params, source: source});
	if(variableInfo && variableInfo.srcVariable) {
	var list = variableInfo.resultList ? variableInfo.resultList : [variableInfo.text];

Both resultList and text properties of variableInfo are undefined and thus this is the value returned by the operator.

Furthermore @Jermolene, would it not be appropriate to fallback to the field[] operator, if the operator specified does have a dot character but no function with that name exists?

Otherwise filters of this form would start to fail: [draft.of[New Tiddler]] and this would be a backwards compatibility break.

[kookma]

{{{ [doesnot.exist[]] }}}

I confirm the error. Win 10, Chrome 113

[Jermolene]

Thanks @AnthonyMuscio @saqimtiaz @kookma, fix coming up