Session.save() and Observation listeners in a SlingAllMethodsServlet

[Lukas Eder]

I feel that I have stumbled upon a very subtle bug or API misuse on my
side when using SlingAllMethodsServlet. The following is a shortened
version of my code:

    @Override
    protected void doPost(
        SlingHttpServletRequest request,
        SlingHttpServletResponse response
    ) throws ServletException, IOException {

        // [...]
        Resource resource = request.getResource();
        Node node = resource.adaptTo(Node.class);
        node.setProperty("x", "y");
        node.getSession().save();
        // [...]

    }



Now, through debugging, I have noticed that the change I made above did
not update Jackrabbit's index. Before I try to write up a reproducible
test case:

1. Is this a known issue?
2. Am I misusing API (e.g. session.save())?

I've noticed that Sling's PostOperation uses ResourceResolver.commit(),
although that doesn't seem to make the difference.

Cheers
Lukas