Preview release of ppxlib.0.37.0 with 5.4 compat

[NathanReb]

We're releasing from a 0.37 branch this time as main already includes the 5.3 AST bump which would make it harder to test OCaml 5.4 as it might break a few rev deps.

I'm doing this as a preview for now as we might want to incorporate a couple other features in the actual 0.37.0 release.

CC @patricoferris.

[mseri]

@mtelvers something seems of with the ci on the lint job, it was working a few days ago

[shonfeder]

Hi @NathanReb, :) is this still pending possible additions?

[NathanReb]

What do you mean @shonfeder ? This is a preview version to help testing OCaml 5.4. We'll delete this when the actual 0.37.0 release comes out.

[NathanReb]

If you're talking about this PR: no, I think it's pretty much ready to go.

If you're talking about ppxlib.0.37.0: yeah, we're hoping to include other features in there eventually!

[shonfeder]

Sorry for being unclear and confused. I was referring to this PR.

Are the revdeps failures here expected?

[mseri]

There is only one failure that I am worried about:

#=== ERROR while compiling vlt.0.2.5 ==========================================#
# context              2.3.0 | linux/x86_64 | ocaml-base-compiler.4.14.2 | file:///home/opam/opam-repository
# path                 ~/.opam/4.14/.opam-switch/build/vlt.0.2.5
# command              ~/.opam/opam-init/hooks/sandbox.sh build dune build -p vlt -j 255 @install
# exit-code            1
# env-file             ~/.opam/log/vlt-7-050377.env
# output-file          ~/.opam/log/vlt-7-050377.out
### output ###
# File "ppx/dune", lines 2-11, characters 0-162:
#  2 | (rule
#  3 |  (deps (:< vlt_ppx.ml.cppo))
#  4 |  (targets vlt_ppx.ml)
#  5 |  (action
#  6 |   (with-stdout-to
#  7 |    %{targets}
#  8 |    (run %{bin:cppo} -V "PPXLIB:%{version:ppxlib}" %{<})
#  9 |   )
# 10 |  )
# 11 | )
# (cd _build/default/ppx && /home/opam/.opam/4.14/bin/cppo -V PPXLIB: vlt_ppx.ml.cppo) > _build/default/ppx/vlt_ppx.ml
# Error: Invalid version specification: "PPXLIB:"

Is this a problem in ppxlib, cppo or something else?

[NathanReb]

I don't think this is coming from ppxlib!

[NathanReb]

I tried reproducing this by building vlt locally but everything just builds fine, both on vlt#main and 0.2.5.

[NathanReb]

Any way we can see the full logs? I'm curious to see what %{version:ppxlib} gets expanded to. I had suprising results running it locally, it does not seem to use the opam version.

[NathanReb]

According to the dune documentation on the matter (https://dune.readthedocs.io/en/stable/advanced/package-version.html), I think it might not be very well suited to preview releases such as this one where we simply point to the github source archive for a regular commit.

I'm still surprised it would produce something that would get rejected by cppo though.

[mseri]

Thanks for looking into it. You'll get some very partial testing from the CI with this issue in place, but this is has the avoid-version flag so should not create disruption outside people working on bleeding edge 5.4 development (which are expecting troubles anyway 😅). Should we go on with merging or you want to see if there is a solution for this?

[NathanReb]

Let's go ahead and merge, as you point out, this is mostly for 5.4 testing. If the issue arises again when I go through the actual 0.37.0 release, I'll investigate this more thoroughly but I suspect it won't!