i agree with your opinion, and it's backed by the spec/javadocs.
in most cases the consumer will access the bindings from an actual script (e.g.
HTL), and in that case it should not make any difference for them.
stefan
>-----Original Message-----
>From: Jörg Hoh <jhoh...@googlemail.com.INVALID>
>Sent: Friday, February 4, 2022 12:01 PM
>To: Sling Developers List <dev@sling.apache.org>
>Subject: [Scripting] Bindings returning null
>
>Hi,
>
>I am currently working on a number of smaller performance improvements, and
>I found that some BindingsValuesProvider could benefit from providings
>lazily. In that case the binding is added, but the value is only resolved
>when the value of the binding is actually needed, instead of resolving them
>when adding the binding [1]. As these bindings are added very often, but
>not always used, a small improvement in the area of a few hundred
>microseconds can accumulate to a 2-digit number of milliseconds for a
>complex request;
>
>The implementations of the BindingValuesProvider#addBindings() currently
>often perform checks if the binding should be added at all. In the case of
>a failed check the binding would not be added at all.
> With the dynamic resolution this is hardly possible, it would defeat the
>purpose of delaying the resolution (including these checks) to a time when
>it's absolutely necessary. In the case of the dynamic resolution with a
>failed check this just leaves the option to return "null" for that binding.
>
>The javax.script.Bindings#get spec [2] allows to return null in 2 cases:
>* the mapping is not present
>* the mapping returns a null
>
>So technically this change is covered by the spec, but I don't know if all
>users of the bindings always check for null but have used some other
>approach instead:
>
>if (bindings.containsKey(BINDING)) {
> Object o = bindings.get(BINDING);
> assertNotNull(o);
>}
>
>which is incorrect according to the spec, but might have worked in the
>past.
>
>In my opinion we should adjust these BindingsValuesProviders and require
>the consumers of these bindings to make sure that they do the null-check as
>required by the spec.
>
>WDYT?
>
>
>Jörg
>
>
>[1]
>https://github.com/apache/sling-org-apache-sling-
>api/blob/master/src/main/java/org/apache/sling/api/scripting/LazyBindings.j
>ava
>[2]
>https://docs.oracle.com/javase/8/docs/api/javax/script/Bindings.html#get-
>java.lang.Object-
>
>
>--
>Cheers,
>Jörg Hoh,
>
>https://cqdump.joerghoh.de
>Twitter: @joerghoh
