sys/net/nanocoap: add missing dependency to sock_udp

[maribu]

Contribution description

As the title says

Testing procedure

In master:

$ make BOARD=native64 tests-nanocoap flash test -j 32 -C tests/unittests
[...]
In file included from /home/marian.buschsieweke@ml-pa.loc/Repos/software/RIOT/master/sys/net/application_layer/nanocoap/nanocoap.c:31:
/home/marian.buschsieweke@ml-pa.loc/Repos/software/RIOT/master/sys/include/net/nanocoap_sock.h:211:16error: field ‘udp’ has incomplete type
  211 |     sock_udp_t udp;                         /**< UDP socket     */
      |                ^~~
/home/marian.buschsieweke@ml-pa.loc/Repos/software/RIOT/master/sys/include/net/nanocoap_sock.h:501:1:error: unknown type name ‘kernel_pid_t’
  501 | kernel_pid_t nanocoap_server_start(const sock_udp_ep_t *local);
      | ^~~~~~~~~~~~

This PR

$ make BOARD=native64 tests-nanocoap flash test -j 32 -C tests/unittests
make: Entering directory '/home/marian.buschsieweke@ml-pa.loc/Repos/software/RIOT/master/tests/unittests'
Building application "tests_unittests" for "native64" with CPU "native".
[...]
  text	  data	   bss	   dec	   hex	filename
149538	 36040	 78120	263698	 40612	/home/marian.buschsieweke@ml-pa.loc/Repos/software/RIOT/master/tests/unittests/bin/native64/tests_unittests.elf
[...]
main(): This is RIOT! (Version: 2026.01-devel-436-g816f586-sys/net/nanocoap/missing-dep)
.....................................
OK (37 tests)

Issues/PRs references

None

[mguetschow]

Oh wait, but this looks wrong: why would nanocoap being the parser/generator part of the coap api require sock_udp?

In fact, the error message you provide shows an include of nanocoap_sock.h, which should probably not be in sys/net/nanocoap from my understanding.

[maribu]

Well, in theory nanocoap should only be the parser. But in reality nanocoap is a hot mess. sys/net/application_layer/nanocoap/nanocoap.c includes nanocao_sock.h and therefore depends on sock_udp.h.

[mguetschow]

Ah fun, just digged where this is coming from, a commit co-authored by me :P

feeb684

Don't we have a way to fix this in nanocoap_sock, e.g. by doing the observe stuff before calling coap_handle_req? And thereby fixing the dependencies in nanocoap.c

[maribu]

To be honest, coap_handle_req() is already out of scope of the CoAP message parsing and message building that pure nanocoap is supposed to be.

[mguetschow]

I see. If you think moving these three lines out of coap_handle_req is too cumbersome, I would at least add comments both on those lines and in the Makefile.dep pointing out that this is not the proper dependency/place to have it.

Just imagining myself looking at this in some months from now and being completely confused about it again.

[riot-ci]

Murdock results

✔️ PASSED

1818821 sys/net/nanocoap: add missing dependency to sock_udp

Success	Failures	Total	Runtime
11005	0	11005	08m:25s

Artifacts

• Documentation preview

[mguetschow]

Thanks! Let's squash 🎾

[miri64]

Shunting in favor of the release note PR