Build failure on gluon's kqueue stub with Big Sur (Apple SDK 11)

[huwaireb]

Problem

It seems like we're implicitly casting struct kevent * to const char * and that's a problem in older versions of the Apple SDK. https://github.com/riot-ml/riot/blob/fb6910bd549bb052c30a838ddbd29bd83049e4af/gluon/sys/unix/gluon_unix_kqueue.c#L73

Environment Info

[!NOTE] I'm not on Big Sur, I'm using Nix to build Riot which provides it's own Apple SDK, and it lacks Apple SDKs above 11.0 (can share flake if needed). & Big Sur is only ~4 years old so I believe compatibility should be ensured.

SDK: 11, Darwin: xnu-7195 sys/event.h

[stuckinforloop]

Reopening the issue because I'm facing this when installing Riot v0.0.8. Following are some logs which can help with debugging:

[ERROR] The compilation of gluon.0.0.8 failed at "dune build -p gluon -j 10 @install".

#=== ERROR while compiling gluon.0.0.8 ========================================#
# context     2.1.5 | macos/arm64 | ocaml.5.1.1 | https://opam.ocaml.org#4bb8cb8b
# path        ~/.opam/default/.opam-switch/build/gluon.0.0.8
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p gluon -j 10 @install
# exit-code   1
# env-file    ~/.opam/log/gluon-88181-9fbc4c.env
# output-file ~/.opam/log/gluon-88181-9fbc4c.out
### output ###
# gluon_unix_kqueue.c:73:36: error: incompatible function pointer types passing 'value (struct kevent *)' (aka 'long (struct kevent *)') to parameter of type 'value (*)(const char *)' (aka 'long (*)(const char *)') [-Wincompatible-function-pointer-types]
# [...]
#                                    ^~~~~~~~~~~~~~~~~~~~~~
# /Users/neel/.opam/default/lib/ocaml/caml/alloc.h:57:44: note: passing argument to parameter 'funct' here
# CAMLextern value caml_alloc_array (value (*funct) (char const *),
#                                            ^
# gluon_unix_kqueue.c:73:60: warning: incompatible pointer types passing 'struct kevent **' to parameter of type 'const char *const *' [-Wincompatible-pointer-types]
#     event_array = caml_alloc_array(kqueue_event_to_record, event_ptrs);
#                                                            ^~~~~~~~~~
# /Users/neel/.opam/default/lib/ocaml/caml/alloc.h:58:57: note: passing argument to parameter 'array' here
#                                    char const * const * array);
#                                                         ^

Other specifications:

• macos 14.3.1 (Macbook M3 Pro)
• target: arm64-apple-darwin23.3.0
• gcc version: Apple clang version 15.0.0 (clang-1500.3.9.4)

[huwaireb]

Hey @stuckinforloop,

The fix that landed in #64 didn't manage to land in time prior to the latest (0.0.8) release. See https://github.com/riot-ml/riot/compare/0.0.8...main.

I'd suggest using riot from source as mentioned here (heads up, it might be a little tedious 😥).

It's weird why it broke on 14.3.1 considering it's the latest (cc @leostera a new release might be necessary)

we can re-close if this fixes your problem @stuckinforloop.

[stuckinforloop]

If I follow the same instructions as in CONTRIBUTING.md file, I'm getting the following issue:

Package conflict!
  * Missing dependency:
    - config >= 0.0.2
    not available because the package is pinned to version 0.0.1

If I remove the pin for config package and run add the remaining dependencies, I'm getting an error for dune build

[ERROR] The compilation of riot.0.0.8 failed at "dune build -p riot -j 10 @install".

#=== ERROR while compiling riot.0.0.8 =========================================#
# context     2.1.5 | macos/arm64 | ocaml.5.1.1 | pinned(git+https://github.com/riot-ml/riot#2d7386bf6e8adc934ba10e2fa24e711f6534af5f)
# path        ~/personal/touch-tui/_opam/.opam-switch/build/riot.0.0.8
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p riot -j 10 @install
# exit-code   1
# env-file    ~/.opam/log/riot-74185-334f9f.env
# output-file ~/.opam/log/riot-74185-334f9f.out
### output ###
# (cd _build/default && /Users/neel/personal/touch-tui/_opam/bin/ocamlc.opt -w -40 -g -bin-annot -I riot/lib/.lib.objs/byte -I /Users/neel/personal/touch-tui/_opam/lib/angstrom -I /Users/neel/personal/touch-tui/_opam/lib/asn1-combinators -I /Users/neel/personal/touch-tui/_opam/lib/base64 -I /Users/neel/personal/touch-tui/_opam/lib/bigstringaf -I /Users/neel/personal/touch-tui/_opam/lib/bytestri[...]
# File "riot/lib/ssl.ml", line 97, characters 11-47:
# 97 |       | Ok (state', `Response resp, `Data data) ->
#                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# Error: This pattern matches values of type 'a * 'b * 'c
#        but a pattern was expected which matches values of type
#          Tls.Engine.state * [ `Eof ] option *
#          [ `Response of Cstruct.t option ] * [ `Data of Cstruct.t option ]