+lwt.3.0.0 - concurrency library

[aantron]

Lwt 3.0.0 is finally here.

Changelog:

Breaking

• These changes were originally announced in release 2.7.0 (LLVM 3.2 fails to install on Mac OS X 10.6.8 with ocaml "system" version 4.00.1 #308).
• Lwt_engine.libev now has an optional argument for selecting the libev back end (cohttp, uri and github updates #269, Lzo package #294, Jeremy Yallop).
• Lwt_io.establish_server has been changed to make it more difficult to leak file descriptors (weberizer 0.7.2 #258, ocaml-inotify #260).
• Lwt_io.shutdown_server now evaluates to a promise, which completes when the listening socket's close(2) operation completes (Added lacaml.7.0.6 #259).
• Lwt_unix.bind now evaluates to a promise, because the bind(2) system call can block for Unix domain sockets (add trunk opam switch #296, requested David Sheets).
• ocamlfind packages lwt.react, lwt.ssl, lwt.glib are replaced by lwt_react, lwt_ssl, lwt_glib. These have been separate OPAM packages, under those names, since 2.7.0 (Updated Lacaml to version 7.0.7 #301).

I originally wanted to estimate the failed revdeps from this locally. However, since I expect this to still fail the revdeps build at least once, I think it makes more sense to just let it run, and try to add the right constraints afterwards.

cc @mfp @c-cube

[camelus]

❗ opam-lint warnings 2d5d484

• lwt.3.0.0 has some warnings:

  • warning 41: Some packages are mentionned in package scripts of features, but there is no dependency or depopt toward them: "lablgtk", "lwt_glib",
    "lwt_react", "lwt_ssl", "react", "ssl"

• These packages passed lint tests: lwt_glib.1.0.1, lwt_react.1.0.1, lwt_ssl.1.0.1

---

✅ Installability check (6502 → 6506)

• new installable packages (4): lwt.3.0.0 lwt_glib.1.0.1 lwt_react.1.0.1 lwt_ssl.1.0.1

[aantron]

lwt_glib is failing to build in CI due to missing external library glib (pkg-config name glib-2.0). I'm not sure how to add a dependency on it – there doesn't seem to be a conf- package for either gtk or glib. I'm not sure how it built in the past, either. lwt_glib used to have a dependency on lablgtk, but that package only has depopts, only on things like conf-gtksourceview. I can't find the logs from the previous builds in #8196, but I doubt conf-gtksourceview and the other depopts were installed, so I'm assuming that gtk was somehow present in the build containers anyway.

Any ideas? Should I add a conf-gtk and/or conf-glib package to OPAM?

[aantron]

Ok, I see that lablgtk has depexts built into it directly. Perhaps those should be factored out? lwt_glib doesn't need all of lablgtk, only the external dependencies.

[aantron]

cc @garrigue

[avsm]

It might be useful to just create one PR with only the base Lwt package, to test revdeps for that in isolation. Then followup PRs that include Lwt and the optional new packages like Lwt_glib

[aantron]

Thanks. I also thought to just add lablgtk temporarily to lwt_glib, but separate PRs is probably wiser. Base package is in above linked PR.

[avsm]

@aantron how feasible is it to move lwt.ppx to a separate ppx_lwt library to remove that dependency as well? it's very brittle with new compiler versions.

[aantron]

It's certainly technically very feasible. It's probably wiser to port it to ocaml-migrate-parsetree, though.

Actually, I don't think we've had a PPX breakage on my watch. Last one was in 4.03. Is it breaking in 4.06 or something? Or do you mean it's brittle because it takes time to adapt ppx_tools/ocaml-migrate-parsetree?

There is a related issue here: ocsigen/lwt#266

[aantron]

Closing in favor of #8956. I think it makes more sense to build up the history and fix dependencies there.