Tooltip: renders its children while in the middle of using WidgetBuilder

Describe the bug Tooltip renders its children while being in the middle of using WidgetBuilder. PrimeFaces reuses a single WidgetBuilder instance. If the children use WidgetBuilder too, they risk affecting its internal state (namely the endFunction field) in such a way, that later Tooltip won’t finish its widget properly.

Reproducer

Environment:

• PF Version: 6.2.30
• PFE Version: 6.2.10
• JSF + version:
• Affected browsers: ALL

To Reproduce Open the page, see error in console (Uncaught SyntaxError: Unexpected end of input in Firefox).

Expected behavior No errors, valid markup.

Sample XHTML

<pe:tooltip>
	<p:dataGrid columns="1">
		Ayy
	</p:dataGrid>
</pe:tooltip>

Furthermore Related discussion and changes here: https://github.com/primefaces/primefaces/issues/3110#issuecomment-354194466 - this is when @tandraschko changed wb.append("},true);});"); to wb.finish(), which uncovered the problem. Now, seemingly by a happy accident, this problem doesn’t happen in PF10+PFE10. Because WidgetBuilder gets inited with endFunction=false not on a widget by widget basis anymore, but:

if ((context.isPostback() && context.getPartialViewContext().isAjaxRequest()) || configuration.isMoveScriptsToBottom()) {
    this.init(widgetClass, widgetVar, id, false);
}
else {
    context.getResponseWriter().write("$(function(){");
    this.init(widgetClass, widgetVar, id, true);
}

So either all widgets per request have endFunction=false, or all have it=true. Still, this could be a problem in the future. Perhaps

1. Tooltip should render it’s children to a buffer before building the widget.
2. PrimeFaces’ WidgetBuilder should prevent such misuse by adding a new boolean like this:

private boolean building;

init() {
    checkState(!building);
    building = true;
}

finish() {
    building = false;
}

[VsevolodGolovanov]

@melloware, yes, that’s good.

[melloware]

@VsevolodGolovanov can you review this fix? I just basically moved that above the wb.init method.

https://github.com/primefaces-extensions/primefaces-extensions/commit/35597fc868c7af152bfd1ce3bdcc9317729103c8