Overlapped Ressource in Composite Operation

[sbernard31]

LWM2M v1.1 introduce Composite Operation.

With those composite operation, you can imagine that you can ask for overlapped Resources.
Eg. if you try to do /3 + /3/0/1 in same Read-Composite request.

AFAIK, there is nothing clear in the LWM2M specification which clearly specify if this is allowed or not.
But this seems to be a useless use case as /3/0/1 value will be included in /3.
(We could also imagine that someone ask for /3 twice in same request ...)

Currently at Leshan we don't support this overlapped resources as supporting it make the code more complex for a useless use case.

Note that in 6.1.3.19 LightweightM2M-1.1-int-229 – Read-Composite Operation from Enabler Test Specification (Interoperability) for Lightweight M2M Draft Version 1.1 – 12 Sep 2019, the test about Read-Composite uses overlapped ressources :

1. is it intended ?
2. for in interoperability test, I'm not sure this is a good idea to use this kind of overlapped resources, I think this could be changed. If you disagree please could you share rational behind this choice ? 🙏

[JaroslawLegierski]

Maybe a good idea would be replace /3 by e.g. /3/0/0 or /3/0/1 in 6.1.3.19 LightweightM2M-1.1-int-229 – Read-Composite Operation test description ?

[mkgillmore]

Resolved in Latest ETS relese

[sbernard31]

@mkgillmore where can we find this lastest ETS release.
I didn't find anything here : https://www.openmobilealliance.org/release/LightweightM2M/ETS/

[jpradocueva]

@sbernard31 the latest ETS v1.2 is available on the above folder, see here: OMA-ETS-LightweightM2M_INT-V1_2-20231003-A.pdf

[sbernard31]

@jpradocueva, I followed your link and look at chapter 6.3.19. LightweightM2M-1.1-int-229 -- Read-Composite Operation.(which seems to be the replacement of 6.1.3.19 LightweightM2M-1.1-int-229 – Read-Composite Operation).

And I see :

Test Procedure

1. Server performs a Read-Composite (CoAP FETCH) on the following combination of Objects, Object Instances,
   Resources and Resources Instances:

• Device Object (/3),
• LwM2M Server Object Instance (/1/x, where x in a LwM2M Server Object Instance),
• Lifetime Resource (/1/x/1),
• Error Code Resource Instance (/3/0/11/0)

So, overlapped resources are still there. So I'm not sure to understand how this is resolved ? 🤔
Did I miss something ?

[jpradocueva]

@sbernard31. I am sorry I just wanted to point out where the ETS for LwM2M v1.2 was. The group will have to deal with the technical comment.