ocaml dune 3

[Richard W.M. Jones]

Annoyingly now that I've done the OCaml rebuild, I discovered that the
version of Dune that we're shipping is quite old.  Fedora Rawhide
ships 2.9.3, latest upstream is 3.3.1.

https://bugzilla.redhat.com/show_bug.cgi?id=2002676

This wouldn't necessarily matter, but I found a new package that
depends on 3.x:

https://bugzilla.redhat.com/show_bug.cgi?id=2099754

Well, it _may_ work with 2.9 (after hacking the dune-project file) but
it fails a bit later because of some missing dependencies so I'm
not entirely sure.

Anyhow, I wonder if there's a reason why we're sticking with dune 2.9,
or if I can upgrade it?

Rich.

Hi,

------- Original Message -------
On Wednesday, June 22nd, 2022 at 7:32 PM, Richard W.M. Jones  wrote:
> Anyhow, I wonder if there's a reason why we're sticking with dune 2.9,
> or if I can upgrade it?

I don't think we've a particular reason of sticking with 2.9.
BTW, thank you for taking care of the many ocaml packages as always :)

Best regards,
Andy

[Jerry James]

On Wed, Jun 22, 2022 at 5:32 AM Richard W.M. Jones  wrote:
> Annoyingly now that I've done the OCaml rebuild, I discovered that the
> version of Dune that we're shipping is quite old.  Fedora Rawhide
> ships 2.9.3, latest upstream is 3.3.1.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=2002676
>
> This wouldn't necessarily matter, but I found a new package that
> depends on 3.x:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=2099754
>
> Well, it _may_ work with 2.9 (after hacking the dune-project file) but
> it fails a bit later because of some missing dependencies so I'm
> not entirely sure.
>
> Anyhow, I wonder if there's a reason why we're sticking with dune 2.9,
> or if I can upgrade it?

I've actually had an update to dune 3.x waiting in the wings for some
time.  You can see it here:
https://copr.fedorainfracloud.org/coprs/jjames/Infer/.  (This COPR
repo needs a lot of updating due to the recent OCaml mass rebuild.
I'll try to get to that in the next few days.)

Things to be aware of:
1. There is a new dependency, ocaml-pp.  Like ocaml-csexp, it has to
be hacked up to be built without dune, since we need to build dune
with it.  Gotta love these circular dependencies.
2. Speaking of circular dependencies, dune 3.x has a new module,
dune-rpc-lwt, that depends on lwt.  And, of course, lwt transitively
depends on dune.  Nothing in Fedora currently needs dune-rpc-lwt, so
my inclination is to patch it out for now and deal with it later if
such a dependency appears.
3. Dune has several modules that we currently bundle together in
ocaml-dune-devel.  I'm starting to see dependencies arise on
individual modules.  It may be worth our while to break at least some
of them out into separate packages.  In particular, there are lots of
dependencies on dune-configurator, and I am starting to see some on
dune-build-info as well.
4. Dune 3.x removes some old dune 1.x compatibility code.  This breaks
alt-ergo, but I have a patch to work around the issue.

I'll attach the spec file and patch I have been experimenting with.  I
think this spec file takes #3 too far; it breaks *every* module out
into an RPM package, which is probably overkill.

[Jerry James]

On Wed, Jun 22, 2022 at 8:19 AM Jerry James  wrote:
> There is a new dependency, ocaml-pp.  Like ocaml-csexp, it has to
>
> be hacked up to be built without dune, since we need to build dune
> with it.  Gotta love these circular dependencies.

Here is a review request for ocaml-pp:

https://bugzilla.redhat.com/show_bug.cgi?id=2101964

Does anyone have time to review it?

We will also need a tiny tweak to ocaml-srpm-macros to account for a
path change in dune 3.x.  I will file a PR today for that.  Once
ocaml-pp is ready and the ocaml-srpm-macros change has been merged and
built, we should be able to upgrade the ocaml-dune package.  I've done
a little more work on the spec file I posted earlier, and I think I'm
happy with it now.

Once all *that* is done, we can introduce ocaml-camlp-streams.

[Jerry James]

On Tue, Jun 28, 2022 at 4:24 PM Jerry James  wrote:
> We will also need a tiny tweak to ocaml-srpm-macros to account for a
> path change in dune 3.x.

It turns out that there is a simple workaround to avoid this change,
so never mind.  All we need is ocaml-pp, which Richard is working on.

[Jerry James]

On Tue, Jun 28, 2022 at 5:33 PM Jerry James  wrote:
> It turns out that there is a simple workaround to avoid this change,
> so never mind.  All we need is ocaml-pp, which Richard is working on.

Dune 3.3.1 is now available in Rawhide.