From: Xavier Dury <>
Date: Fri, 15 Jan 2016 19:58:30 +0100

Ok, I will try with #{} instead of #{id}.
I originally thought it was a prettyfaces bug. If you have better arguments than me, you could still leave a comment at

Date: Fri, 15 Jan 2016 19:27:13 +0100


On Fri, Jan 15, 2016 at 7:15 PM, Xavier Dury <> wrote:

<url-mapping id="document">
        <pattern value="/document/#{id}" /> <view-id value="/document.xhtml" /></url-mapping>
I don't think replacing #{id} with #{} in the prettyfaces configuration will work.
Okay, so it's PrettyFaces that essentially does the write to #{id} which will end up in request scope? (I don't know PrettyFaces that well).
Depending on what PrettyFaces exactly does you could try it though. If it's a general value expression where whatever comes after /document/ is written to it may actually have a chance of working.
I don't know if there are other places in the code where UIViewRoot.getViewMap() is being called without considering that the current view may be transient.

I think the view being transient or not does not even matter that much. After all, you can also have a view that simply doesn't use a form (so no state) or have state written to the client.
What (IMHO) matters most is that code, and specifically frameworks, should always be wary of accidentally creating sessions when not strictly necessary.

Date: Fri, 15 Jan 2016 17:18:57 +0100


On Fri, Jan 15, 2016 at 4:31 PM, Xavier Dury <> wrote:

        String attribute = (String) property;

        FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);

        ExternalContext ec = facesContext.getExternalContext();

        if ((ec.getRequestMap().get(attribute)) != null) {

                ec.getRequestMap().put(attribute, val);

        } else if ((facesContext.getViewRoot()) != null && (facesContext.getViewRoot().getViewMap().get(attribute)) != null) {

                facesContext.getViewRoot().getViewMap().put(attribute, val);

        } else if ((ec.getSessionMap().get(attribute)) != null) {

                ec.getSessionMap().put(attribute, val);

        } else if ((ec.getApplicationMap().get(attribute)) != null) {

                ec.getApplicationMap().put(attribute, val);

        } else {

                // if the property doesn't exist in any of the scopes, put it in

                // request scope.

                ec.getRequestMap().put(attribute, val);


This code seems indeed problematic. The view map is created only to check it, which not only causes an annoying warning, it also causes the creation of a session.
The same thing holds for the session map check. ec.getSessionMap().get(attribute) will create a session, even when this would not be needed.
For some types of applications, the needless creation of sessions is a serious problem. So regardless of the message being annoying or not, or clear or not, this session creation seems problematic to me.
The question is; how strict is the spec about mandating this?
Regardless, wouldn't changing the value expression mentioned in the issue to one that explicitly contains the scope work around a particular instance of this problem?
ValueExpression ve = ef.createValueExpression(context.getELContext(), "#{}", Object.class);

instead of
ValueExpression ve = ef.createValueExpression(context.getELContext(), "#{id}", Object.class);