Lwt 3.3.0, Lwt_ppx 1.1.0 – promises and concurrent I/O

[aantron]

Perhaps the main highlight of the release is that @gabelevi has restored stack trace generation in the PPX, which should be a big help to everyone.

Full changelog:

Bugs fixed

• Restore backtrace support (Fix lwt_ppx backtraces with reraise ocsigen/lwt#554, Reraise in lwt ocsigen/lwt#556, Gabe Levi).
• Serious logic error that could cause Lwt to hang or crash (Hanging Lwt_main.run case ocsigen/lwt#549, reported @koen-struyve).
• All Lwt_list functions are now tail-recursive (Issue 395: Add tests for stack safety in Lwt_list. ocsigen/lwt#538, Joseph Thomas).

Additions

• Support ;%lwt syntax in the PPX (Support ;%lwt as sequence syntax -- backwards incompatible in some cases ocsigen/lwt#307, Hezekiah Carty).
• Lwt_stream.iter_n (Add Lwt_stream.iter_n ocsigen/lwt#312, Hezekiah Carty).

Miscellaneous

• Testing improvements (Lwt sequence tests ocsigen/lwt#536, Lwt sequence tests 2 ocsigen/lwt#541, @cedlemo).
• Documentation improvements (Document Lwt_io.printf flushing behavior ocsigen/lwt#544, Link Lwt-related libraries in README.md ocsigen/lwt#546, Documentation improvements: Lwt_main.run and Lwt_io.wait_read/wait_write ocsigen/lwt#547, Replace notify=>signal in Lwt_condition documentation ocsigen/lwt#553, Fix an error and a typo in the manual. ocsigen/lwt#559, Daniil Baturin, Jason Evans, Jess Smith, Milo Turner).

[camelus]

❗ opam-lint warnings e018976

• lwt.3.3.0 has some warnings:

  • warning 41: Some packages are mentionned in package scripts of features, but there is no dependency or depopt toward them: "lwt_camlp4", "lwt_log",
    "lwt_ppx"

• These packages passed lint tests: lwt_ppx.1.1.0

---

✅ Installability check (8395 → 8397)

• new installable packages (2): lwt.3.3.0 lwt_ppx.1.1.0

[hcarty]

Looking through the failures, most seem to be unrelated to this PR.

EDIT: I won't be able to check all of the failures, but I'll add the ones I've checked below.

• arakoon has an unrelated missing external dependency
• aws tries and fails to dbm after building aws
• brotli and brozip fail due to a missing system package
• ezirmin and irmin fail due to what looks related to the recent re release.

[aantron]

Thanks @hcarty. I checked the rest, and none of those are broken due to Lwt either.

[aantron]

The Travis problems are also not caused by Lwt.

[hcarty]

Thank you @aantron! Merging.

[aantron]

Thanks!