PrettyFaces causes NPE in applications using MyFaces 2.2 and Faces Flows

[wtlucy]

Applications using JSF 2.2 Faces Flows and MyFaces don't work with PrettyFaces. This NPE is thrown:

java.lang.NullPointerException
	at org.apache.myfaces.application.NavigationHandlerImpl.getNavigationCaseFromFlowStructure(NavigationHandlerImpl.java:905)
	at org.apache.myfaces.application.NavigationHandlerImpl.getNavigationCommand(NavigationHandlerImpl.java:720)
	at org.apache.myfaces.application.NavigationHandlerImpl.getNavigationCase(NavigationHandlerImpl.java:394)
	at com.ocpsoft.pretty.faces2.application.PrettyNavigationHandler.getNavigationCase(PrettyNavigationHandler.java:121)
	at org.ocpsoft.rewrite.faces.RewriteNavigationHandler.getNavigationCase(RewriteNavigationHandler.java:116)
	at org.apache.myfaces.shared.renderkit.html.util.OutcomeTargetUtils.getOutcomeTargetHref(OutcomeTargetUtils.java:81)
	at org.apache.myfaces.shared.renderkit.html.HtmlRendererUtils.getOutcomeTargetHref(HtmlRendererUtils.java:1602)
	at org.apache.myfaces.shared.renderkit.html.HtmlLinkRendererBase.renderOutcomeLinkStart(HtmlLinkRendererBase.java:1006)
	at org.apache.myfaces.shared.renderkit.html.HtmlLinkRendererBase.encodeBegin(HtmlLinkRendererBase.java:145)
	at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:597)
	at javax.faces.component.UIComponentBase.encodeAll(UIComponentBase.java:527)

It looks to me like PrettyFaces doesn't correctly register Flows in its PrettyNavigationHandler. PrettyNavigationHandler extends ConfigurableNavigationHandler, however it doesn't do anything with the inspectFlow method that was added in JSF 2.2. To resolve this, PrettyNavigationHandler should probably override inspectFlow and delegate to its parent, since the default implementation of inspectFlow is a no-op.

I've created a sample branch that reproduces this issue: https://github.com/wtlucy/jsf22-examples/tree/prettyfaces_issue/jsf22-flows