Bug: learn-ocaml-client 0.14.0 can't build on win10 wsl2 debian due to ssl 0.5.10 build fails

[ghost]

Related project scope(s): …
learn-ocaml-client.0.14.0, ssl.0.5.10

Bug description

ssl.0.5.10 won't build on wsl2 debian win10, thus cause learn-ocaml-client.0.14.0 fails to install.

ty@sf10up:~$ opam install utop learn-ocaml-client
[NOTE] Package utop is already installed (current version is 2.9.2).
The following actions will be performed:
  ↘ downgrade ssl                0.5.12 to 0.5.10 [required by learn-ocaml-client]
  ∗ install   lwt_ssl            1.1.3            [required by learn-ocaml-client]
  ∗ install   conduit-lwt-unix   1.3.0            [required by cohttp-lwt-unix]
  ∗ install   cohttp-lwt-unix    4.0.0            [required by learn-ocaml-client]
  ∗ install   learn-ocaml-client 0.14.0
===== ∗ 4   ↘ 1 =====
Do you want to continue? [Y/n] Y

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
⬇ retrieved cohttp-lwt-unix.4.0.0  (cached)
⬇ retrieved conduit-lwt-unix.1.3.0  (cached)
⬇ retrieved lwt_ssl.1.1.3  (cached)
⬇ retrieved learn-ocaml-client.0.14.0  (cached)
⬇ retrieved ssl.0.5.10  (cached)
[ERROR] The compilation of ssl.0.5.10 failed at "dune build -p ssl -j 3".

#=== ERROR while compiling ssl.0.5.10 =========================================#
# context     2.1.3 | linux/x86_64 | ocaml-base-compiler.4.12.0 | https://opam.ocaml.org#94fb49a6
# path        ~/.opam/4.12.0/.opam-switch/build/ssl.0.5.10
# command     ~/.opam/4.12.0/bin/dune build -p ssl -j 3
# exit-code   1
# env-file    ~/.opam/log/ssl-28030-12f498.env
# output-file ~/.opam/log/ssl-28030-12f498.out
### output ###
# /home/ty/.opam/4.12.0/lib/ocaml/caml/mlvalues.h:282:23: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
# [...]
#                        ^
# ssl_stubs.c:1179:18: note: in expansion of macro ‘String_val’
#    char *CApath = String_val(ca_path);
#                   ^~~~~~~~~~
# ssl_stubs.c: In function ‘ocaml_ssl_set_client_SNI_hostname’:
# /home/ty/.opam/4.12.0/lib/ocaml/caml/mlvalues.h:282:23: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
#  #define String_val(x) ((const char *) Bp_val(x))
#                        ^
# ssl_stubs.c:1262:20: note: in expansion of macro ‘String_val’
#    char *hostname = String_val(vhostname);
#                     ^~~~~~~~~~



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build ssl 0.5.10
└─
╶─ No changes have been performed

To reproduce

Steps to reproduce the behavior:

On win10 wsl2 debian:
opam install learn-ocaml-client or
opam install learn-ocaml-client.0.14.0 or
opam install ssl.0.5.10

Current configuration

• OS name (and version): win10 21H2 19044.2006
• Browser name (and version): N/A
• learn-ocaml --version: 0.14.0
• git describe --long --always --abbrev=40 --tags: N/A

Additional context

ssl 0.5.12 builds well, if in future can move dependency to this version, things would be great I think.

[ghost]

ps: opam install learn-ocaml-client.0.13.1 works for now.

[erikmd]

Thanks a lot @hxhxd for your very detailed bug report.

@yurug and I plan to release learn-ocaml 0.14.1 in ~7 days, so we'll definitely be able to include a fix for this issue.

I will open a PR and add it to the milestone.

[erikmd]

BTW just FYI, if you want to use learn-ocaml-client from a released version of OCaml, you can also rely on the static binaries available in the GitHub release (easier and faster than building learn-ocaml-client using opam):

https://github.com/ocaml-sf/learn-ocaml/releases/tag/v0.14.0

Basically in a WSL2 terminal, you may want to try:

curl -fSOL https://github.com/ocaml-sf/learn-ocaml/releases/download/v0.14.0/learn-ocaml-client-linux-x86_64
mv learn-ocaml-client{-linux-x86_64,}
chmod a+x learn-ocaml-client
./learn-ocaml-client --help

But you probably were already aware of this.