[Caml-list] Attn: Development Editor, Latest OCaml Weekly News

[Alan Schmitt <alan.schmitt@polytechnique.org>]

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Hello

Here is the latest OCaml Weekly News, for the week of February 17 to 24,
2026.

Table of Contents
─────────────────

OSEC-2026-01 in the OCaml runtime: Buffer Over-Read in OCaml Marshal Deserialization
OCaml 5.4.1 and 4.14.3 released
Ann: Ochat — Try Ochat for terminal-based LLM workflows
Serialport - new serial communication library
Slipshow!
Remote OCaml Distributed Systems Engineer (Linux / Storage / Networking) – whitesky.cloud – EMEA/Asia
Grace 0.3.0 💅, fancy diagnostics library for compilers
Js_of_ocaml / Wasm_of_ocaml 6.3
kqueue-ml 0.5.0
Dune 3.21.0
Other OCaml News
Old CWN


OSEC-2026-01 in the OCaml runtime: Buffer Over-Read in OCaml Marshal Deserialization
════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://inbox.ci.dev/caml-list/c3298309-a06d-4ac8-874c-fe2104078e61@mehnert.org/T/>


Hannes Mehnert announced
────────────────────────

  Dear everyone,

  it is my pleasure to announce the first security announcement of this
  year, and the first coordinated by the new OCaml security response
  team (<https://ocaml.org/security>).

  Please subscribe to the OCaml security announcement mailing list
  (<https://sympa.inria.fr/sympa/info/ocsf-ocaml-security-announcements>)
  to receive all security advisories. To this mailing list I'll only
  copy those affecting the core of OCaml distribution.

  It should any moment now also appear at
  <https://osv.dev/list?q=OSEC-2026-01>

  Human link:
  <https://github.com/ocaml/security-advisories/tree/main/advisories/2026/OSEC-2026-01.md>

  ┌────
  │ id: OSEC-2026-01
  │ modified: "2026-02-17T13:30:00Z"
  │ published: "2026-02-17T13:30:00Z"
  │ aliases: [  GHSA-j26j-m5xr-g23c GHSA-m34r-cgq7-jhfm ]
  │ severity: "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N"
  │ severity_score: "6.8"
  │ affected: "ocaml" {< "4.14.3" | (>= "5" & < "5.4.1")}
  │ events: [
  │    [
  │      git "https://github.com/ocaml/ocaml" [
  │        [fixed "b0a2614684a52acded784ec213f14ddfe085d146"]
  │      ]
  │    ]
  │    [
  │      git "https://github.com/ocaml/ocaml" [
  │        [fixed "e3919fef436f89271bc30bbe8592851f7289fb68"]
  │      ]
  │    ]
  │ ]
  │ references: [
  │    [report 
  │ "https://github.com/ocaml/security-advisories/security/advisories/GHSA-j26j-m5xr-g23c"]
  │ ]
  │ credits: [
  │    [reporter "Justin Timperio"]
  │    [remediation_developer "Nicolás Ojeda Bär"]
  │    [remediation_developer "Xavier Leroy"]
  │    [remediation_developer "Gabriel Scherer"]
  │    [remediation_reviewer "Xavier Leroy"]
  │    [remediation_reviewer "Olivier Nicole"]
  │    [remediation_verifier "Mindy Preston"]
  │    [remediation_verifier "Edwin Török"]
  │    [coordinator "Hannes Mehnert"]
  │ ]
  │ cwe: [ CWE-126 CWE-502 CWE-754 ]
  └────

  *Buffer Over-Read in OCaml Marshal Deserialization*


Summary
╌╌╌╌╌╌╌

  A critical buffer over-read vulnerability in OCaml's Marshal
  deserialization (runtime/intern.c) enables remote code execution
  through a multi-phase attack chain. The vulnerability stems from
  missing bounds validation in the readblock() function, which performs
  unbounded memcpy() operations using attacker-controlled lengths from
  malicious Marshal data.

  Please note that Marshal is not type safe, and you have to be careful
  if you use the deserialization on untrusted input (due to type
  confusion, and remote code execution by design - you can use Marshal
  for code).

  Affected functions: `Marshal.from_channel', `Marshal.from_bytes',
  `Marshal.from_string', `Stdlib.input_value', `Pervasives.input_value'
  when reading data from an untrusted source.


Vulnerability Attack Vector
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Corrupted or malicious marshaled data that causes undefined behaviour
  in the runtime system when unmarshaled.  `input_value' should either
  fail cleanly or produce a well-formed OCaml object, without corrupting
  the runtime system.

  Consequently, this excludes:

  • well-formed marshaled data that produces an OCaml object that is not
    of the type expected by the OCaml code and causes the Ocaml code to
    crash or misbehave

  • misuses of the OCaml runtime system by the program performing
    input_value, such as setting `Debugger.function_placeholder' to the
    wrong function.

  The former issue may be addressed at some point by validating the
  unmarshaled OCaml value against the expected type, using the functions
  from module `Obj' and some kind of run-time type description.

  The latter issue is a bug in the program that unmarshals the data.


Fix
╌╌╌

◊ OCaml runtime

  The OCaml runtime has been hardened with additional bounds checks. An
  exception is raised on bad input.


◊ Third party libraries

  Third party libraries that want to harden their custom Marshal
  deserialization code can follow the example fix for bigarrays from the
  standard library.  There are new macros in `custom.h' called
  `Wsize_custom_data' and `Bsize_custom_data' that return the size in
  words or bytes of the allocated custom destination block. The
  deserializer needs to ensure it only writes data within those bounds.

  This only needs to be done if the library defines a custom type in a C
  binding, and `struct custom_operations''s `deserialize' field is not
  set to `NULL' or `custom_deserialize_default', and `struct
  custom_operations''s `fixed_length' field is set to `NULL' or
  `custom_fixed_length_default'

  Since `Marshal.from*' and `input_value' remain unsafe to use, the fix
  for the OCaml runtime is released, and we wouldn't attempt to
  coordinate updating all deserialization functions in the ecosystem.


Timeline
╌╌╌╌╌╌╌╌

  • Nov 4th 2025: Discovery Date: Discovered first in OxCaml
  • Nov 5th 2025: First Disclosure Date (Jane Street Team): Emailed top
    maintainers, no response.
  • Nov 9th 2025: Second Disclosure Date (OCaml Team): Submitted to
    OCaml/ocaml GitHub Repo as a Security Advisory.
  • Nov 11th 2025: Emailed OCaml Security Mail List: Submitted to OCaml
    over email, responded asking for details.
  • Nov 11th 2025: Third Disclosure (OCaml Security Response Team):
    Submitted to ocaml/security-advisories GitHub Repo as a Security
    Advisory.
  • Dec 16th 2025: Initial patch is developed
  • Dec 17th 2025: Fuzz testing found further issues
  • Dec 24th 2025: Final patch for OCaml is developed
  • Dec 25th 2025: Fuzz testing couldn't find any further issues
  • Jan 2nd 2026: Patch got reviewed by OCaml maintainers
  • Jan 4th 2026: Benchmarking of the patch with good results
  • Jan 6th 2026: Reporter got contacted to confirm
  • Jan 25th 2026: Further related issues discovered by fuzzing
  • Feb 17th 2026: fixed OCaml releases are published, security advisory
    is published


OCaml 5.4.1 and 4.14.3 released
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-5-4-1-and-4-14-3-released/17822/1>


octachron announced
───────────────────

  We have the pleasure of announcing the dual releases of OCaml 4.14.3
  and OCaml 5.4.1, dedicated to the memory of Nicolaas Govert de Bruijn
  on the anniversary of his death.

  Those releases are a collection of safe and valuable runtime bugfixes.
  The OCaml 5.4.1 release also contains a fix for the `-pack' mode for
  macOs and various TSAN fixes.

  More importantly, those new versions harden the Marshal module against
  malicious inputs as described in the security announcement
  [OSEC-2026-01].

  We are encouraging you to switch to those new releases whenever
  possible.

  Don't hesitate to report any bugs on the [OCaml issue tracker].

  See the list of changes below for more details.

  Happy hacking, – Florian Angeletti for the OCaml team.


  *Installation Instructions*

  The base compilers will be soon installable as an opam switch with the
  following commands:

  ┌────
  │ opam update
  │ opam switch create 4.14.3
  │ opam switch create 5.4.1
  └────


  The source code for the release candidate is also directly available
  on:

  • GitHub:
    • <https://github.com/ocaml/ocaml/archive/4.14.3.tar.gz>
    • <https://github.com/ocaml/ocaml/archive/5.4.1.tar.gz>

  • Inria archive:
    • <https://caml.inria.fr/pub/distrib/ocaml-4.14/ocaml-4.14.3.tar.gz>
    • <https://caml.inria.fr/pub/distrib/ocaml-5.4/ocaml-5.4.1.tar.gz>


  *OCaml 4.14.3 (17 February 2026)*

  • [#12070], [#12075], [#13209]: auto-detect whether `ar' support @FILE
    arguments at configure-time to avoid using this feature with
    toolchains that do not support it (eg FreeBSD/Darwin); backport from
    5.3.  (backport by Boris Dobroslavov, original fix by Nicolás Ojeda
    Bär, review by Xavier Leroy, David Allsopp, Javier Chávarri, Anil
    Madhavapeddy)

  • [#12207], [#12222]: Make closure computation linear in the number of
    recursive functions instead of quadratic (Vincent Laviron, report by
    François Pottier, review by Nathanaëlle Courant and Gabriel Scherer)

  • [#13430], [#13434]: protect memory-safety on Lazy.force races
    (Gabriel Scherer and Vincent Laviron, report by Edwin Török, review
    by Vincent Laviron)

  • [#13448], [#13449]: fix a code-generation bug on unsafe array
    accesses at type int32, int64, nativeint, which has been introduced
    in OCaml 4.04.  (Gabriel Scherer, review by Nicolás Ojeda Bär and
    Vincent Laviron, report by Simon Cruanes)

  • [#13516]: Fix regression where error conditions during bytecode
    initialisation caused a segmentation fault rather than being
    properly reported (regression of [#5115] in [#11788]) (David
    Allsopp, review by Nicolás Ojeda Bär)

  • [#13847]: On Windows, maintain a number of threads waiting on the
    master lock to avoid unnecessary context switches (Dmitry Bely,
    review by Antonin Décimo)

  • [#14007], [#14015]: Fix memory corruption when an exception is
    raised during demarshaling.  (Benoît Vaugon, review by David Allsopp
    and Gabriel Scherer)

  • [OSEC-2026-01]: robustify intern.c (Xavier Leroy, review by Damien
    Doligez and Olivier Nicole)

  *OCaml 5.4.1 (17 February 2026)*


[OSEC-2026-01] <https://osv.dev/vulnerability/OSEC-2026-01>

[OCaml issue tracker] <https://github.com/ocaml/ocaml/issues>

[#12070] <https://github.com/ocaml/ocaml/issues/12070>

[#12075] <https://github.com/ocaml/ocaml/issues/12075>

[#13209] <https://github.com/ocaml/ocaml/issues/13209>

[#12207] <https://github.com/ocaml/ocaml/issues/12207>

[#12222] <https://github.com/ocaml/ocaml/issues/12222>

[#13430] <https://github.com/ocaml/ocaml/issues/13430>

[#13434] <https://github.com/ocaml/ocaml/issues/13434>

[#13448] <https://github.com/ocaml/ocaml/issues/13448>

[#13449] <https://github.com/ocaml/ocaml/issues/13449>

[#13516] <https://github.com/ocaml/ocaml/issues/13516>

[#5115] <https://github.com/ocaml/ocaml/issues/5115>

[#11788] <https://github.com/ocaml/ocaml/issues/11788>

[#13847] <https://github.com/ocaml/ocaml/issues/13847>

[#14007] <https://github.com/ocaml/ocaml/issues/14007>

[#14015] <https://github.com/ocaml/ocaml/issues/14015>

Bug fixes:
╌╌╌╌╌╌╌╌╌╌

  • [#14010]: Fix miscompilation / liveness errors for string operations
    (Mark Shinwell, Xavier Clerc, review by Xavier Leroy and Gabriel
    Scherer)

  • [#14065]: Fix function signature mismatch of `__tsan_func_exit' with
    GCC 15.  Check in the configure step if the TSan provided internal
    builtins are the same as what we expect, introduce `caml_tsan_*'
    wrappers for the `__tsan_*' functions we use.  (Hari Hara Naveen S,
    report by Hari Hara Naveen S, review by Gabriel Scherer, Antonin
    Décimo, Olivier Nicole)

  • [#14417]: Fix issue with nested packs on macOS.  (Vincent Laviron,
    report by Kate Deplaix, review by Gabriel Scherer)

  • [#14213]: Fix shadow-stack-related crashes with TSan (Olivier
    Nicole, report by Nathan Taylor, review by Gabriel Scherer and
    Stefan Muenzel)

  • [#14255]: Fix TSan bug with C calls that take many arguments
    (Olivier Nicole and Miod Vallat, report by Nathan Taylor, review by
    Gabriel Scherer)

  • [OSEC-2026-01]: robustify intern.c (Xavier Leroy and Nicolás Ojeda
    Bär, review by Olivier Nicole, Mindy Preston, Edwin Török, and
    Gabriel Scherer)


[#14010] <https://github.com/ocaml/ocaml/issues/14010>

[#14065] <https://github.com/ocaml/ocaml/issues/14065>

[#14417] <https://github.com/ocaml/ocaml/issues/14417>

[#14213] <https://github.com/ocaml/ocaml/issues/14213>

[#14255] <https://github.com/ocaml/ocaml/issues/14255>

[OSEC-2026-01] <https://osv.dev/vulnerability/OSEC-2026-01>


Ann: Ochat — Try Ochat for terminal-based LLM workflows
═══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ochat-try-ochat-for-terminal-based-llm-workflows/17829/1>


Dakota Murphy announced
───────────────────────

  Hi all — I’d like to share a project I’ve been building: *Ochat*.

  • Repo: *[https://github.com/dakotamurphyucf/ochat]*
  • Demo: *[https://youtu.be/eGgmUdZfnxM]*


[https://github.com/dakotamurphyucf/ochat]
<https://github.com/dakotamurphyucf/ochat>

[https://youtu.be/eGgmUdZfnxM] <https://youtu.be/eGgmUdZfnxM>

*What it is*
╌╌╌╌╌╌╌╌╌╌╌╌

  Ochat is a toolkit for building LLM workflows as *plain files*. The
  core format is *ChatMarkdown (ChatMD)*: Markdown plus a small, closed
  XML vocabulary.

  A single ChatMD file is both:

  • the *prompt/program* (model config, tool allowlist, instructions,
    context), and
  • the *auditable transcript* (assistant replies + tool calls + tool
    outputs)

  Because everything is plain text, workflows are reproducible and
  diffable in git.


*Prompt packs: building larger workflows from small agents*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Ochat supports *agent-as-tool*: you can mount one ChatMD prompt as a
  callable tool inside another. This lets you build *prompt packs*
  (planner/coder/reviewer/docs/test triage/etc.) and orchestrate them
  from a top-level prompt, without writing a custom “agent app”.


*chat_tui: a Notty-based terminal UI (runtime uses Eio)*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Ochat ships an interactive terminal UI called *chat_tui*.

  • The UI is built with *Notty*
  • The underlying runtime uses *Eio* (structured concurrency + I/O)

  A ChatMD file can be treated as a “terminal agent”: you author an
  agent prompt as a .md, open it in chat_tui, and run/iterate on it
  while the transcript (including tool traces) is persisted.

  Some chat_tui features:

  • streaming output (assistant text + tool calls + tool outputs)
  • persistent sessions you can resume/branch/export
  • manual context compaction (:compact) for long histories
  • syntax highlighting (including OCaml)
  • AI completions in the text input (to speed up drafting)
  • Vim-ish editing modes and message selection/yank/edit/resubmit
    workflows


*Useful built-in tools (especially for code workflows)*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Ochat includes built-in tools that cover most “agent + repo” loops:

  • read_file / read_dir for safe repo navigation
  • apply_patch for atomic, repo-safe edits
  • webpage_to_markdown for high-signal ingestion (incl. GitHub blob
    fast-path)
  • indexing/retrieval tools for grounding over docs and code
  • optional vision inputs via import_image


*MCP tool import (optional)*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Ochat can also mount external tools via MCP (stdio or HTTP). For
  example, importing Brave Search over stdio:

  ┌────
  │ <tool mcp_server="stdio:npx -y brave-search-mcp" name="brave_web_search" />
  └────


*Quick example: a “custom terminal orchestrator agent”*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This is a complete agent definition (and becomes the runnable “app”
  when opened in chat_tui):


  ┌────
  │ <config model="gpt-5.2" reasoning_effort="medium" />
  │ 
  │ <!-- core built-ins -->
  │ <tool name="read_dir"/>
  │ <tool name="read_file"/>
  │ <tool name="apply_patch"/>
  │ <tool name="webpage_to_markdown"/>
  │ 
  │ <!-- optional: import an external tool via MCP -->
  │ <tool mcp_server="stdio:npx -y brave-search-mcp" name="brave_web_search" />
  │ 
  │ <!-- prompt-pack tools (agents as tools) -->
  │ <tool name="plan"   agent="prompts/pack/plan.md" local/>
  │ <tool name="code"   agent="prompts/pack/code.md" local/>
  │ <tool name="review" agent="prompts/pack/review.md" local/>
  │ 
  │ <developer>
  │ You are the orchestrator. Call plan first.
  │ Keep edits small. Before apply_patch: explain the diff and wait for confirmation.
  │ </developer>
  │ 
  │ <user>
  │ Add a Quickstart section to README.md.
  │ </user>
  └────

  Run it from the repo with:

  ┌────
  │ dune exec chat_tui -- -file prompts/refactor.md
  └────


*Status / caveats*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Provider support today is *OpenAI-only*.
  • The project is moving quickly.


*Feedback / contributors*
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I’d appreciate any feedback or contributions

  If you try it and anything’s confusing or rough, please open an issue.


Serialport - new serial communication library
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-serialport-new-serial-communication-library/17594/3>


Continuing this thread, Mikhail announced
─────────────────────────────────────────

  [Added] (aka implemented) Win32 support, which has not been thoroughly
  tested, but may be useful for certain target use cases.


[Added]
<https://github.com/dx3mod/serialport/commit/d057a004c050234b64e4edbee2c13a04bf4c2734>


Slipshow!
═════════

  Archive: <https://discuss.ocaml.org/t/ann-slipshow/16337/18>


Continuing this thread, Paul-Elliot announced
─────────────────────────────────────────────

  It is with extraterrestrial excitement that I announce the next
  release of Slipshow:

  *Slipshow 0.9.0: Manim Black*

  The featured new feature of this release is the ability to easily
  integrate [Manim] videos in your presentation.

  <https://github.com/user-attachments/assets/f67bb8fc-c288-4ff3-b6bc-e72c12e636a7>

  Note that, compared to just playing a video, you can schedule pauses,
  go faster to the next pause, and go back to the previous pauses, as
  showcased below.


[Manim] <https://www.manim.community/>

Skipping steps and going backward demo
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  <https://github.com/user-attachments/assets/cf1ad264-a5e2-42d2-9f57-09551f3a35e8>

  This release features many more changes, such as TikZ and MermaidJS
  integration! Here is the full changelog:


Added
╌╌╌╌╌

  • Support for Mermaid JS ([#205])
  • Support for syntax highlighting of all highlightjs-supported
    languages and themes ([#200], [#208])
  • Support for MathJax extensions, especially the html extension to
    allow actions to target math elements ([#202])
  • Add KaTeX as a possible alternate renderer ([#202])
  • Added `carousel-fixed-size' to have carousel not change size
    ([#207])


[#205] <https://github.com/panglesd/slipshow/pull/205>

[#200] <https://github.com/panglesd/slipshow/pull/200>

[#208] <https://github.com/panglesd/slipshow/pull/208>

[#202] <https://github.com/panglesd/slipshow/pull/202>

[#207] <https://github.com/panglesd/slipshow/pull/207>


Fix
╌╌╌

  • Fix impossibility to reopen speaker view after closing it on Firefox
    ([#198], issue [#194])
  • Fix impossibility to open speaker view in serve mode ([#198], issue
    [#197])
  • Fix links opening inside iframe ([#198])
  • Fix ending excursions with `ijkl' only when needed ([#207])
  • Fixed video long-step handling ([#207])
  • Removed confusing auto-generated IDs ([#209])
  • Fix `play-media' behavior when facing errors ([#210])


[#198] <https://github.com/panglesd/slipshow/pull/198>

[#194] <https://github.com/panglesd/slipshow/issues/194>

[#197] <https://github.com/panglesd/slipshow/issues/197>

[#207] <https://github.com/panglesd/slipshow/pull/207>

[#209] <https://github.com/panglesd/slipshow/pull/209>

[#210] <https://github.com/panglesd/slipshow/pull/210>


Docs
╌╌╌╌

  • Add how to include TikZ figures in your Slipshow presentation
    ([#206])
  • Add how to include Manim videos in your Slipshow presentation
    ([#207])

  Credit: @vds for the name of the release.

  Thanks again to NLNet for [supporting] the development of Slipshow!


[#206] <https://github.com/panglesd/slipshow/pull/206>

[#207] <https://github.com/panglesd/slipshow/pull/207>

[supporting] <https://nlnet.nl/project/Slipshow/>


Remote OCaml Distributed Systems Engineer (Linux / Storage / Networking) – whitesky.cloud – EMEA/Asia
═════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/remote-ocaml-distributed-systems-engineer-linux-storage-networking-whitesky-cloud-emea-asia/17832/1>


Geert Audenaert announced
─────────────────────────

  We are looking for an OCaml engineer to join *whitesky.cloud* to work
  on low-level distributed infrastructure components.

  *About the work*

  You will work on core building blocks of a sovereign cloud platform,
  including distributed storage and coordination services.

  Examples of related projects:

  • [https://github.com/openvstorage/alba]
  • [https://github.com/openvstorage/arakoon]

  The work involves:

  • Distributed systems design and implementation
  • High-performance networking and I/O
  • Linux systems programming
  • Debugging and optimizing behavior under real production load
  • Long-running services where reliability and correctness matter

  This is *infrastructure work*, not web development.

  —

  *What we are looking for*

  • Strong OCaml experience *or* strong systems programming background
    with willingness to work in OCaml
  • Good understanding of:
    ‣ Linux internals
    ‣ Networking / TCP/IP
    ‣ Concurrency and performance
  • Interest in distributed systems, storage, or consensus algorithms

  We care more about *systems thinking and engineering depth* than about
  specific frameworks.

  —

  *Practical details*

  • Full-time position
  • Fully remote
  • Location: EMEA or Asia
  • Salary: around *€3000/month* (depending on experience and location)

  We know this is not a big-tech salary. We are a small
  engineering-driven company, and the role is aimed at engineers who
  enjoy working close to the system, solving real infrastructure
  problems, and having a direct impact.

  —

  *About whitesky*

  whitesky builds a complete cloud platform based on Linux and KVM,
  focused on sovereignty and control.  The platform is used by MSPs,
  SaaS providers and enterprises to run their own cloud infrastructure.

  You will be working on components that run in production environments
  and form part of a distributed cloud stack.

  —

  If this sounds interesting, please contact:

  *geert.audenaert@whitesky.cloud*

  or send a DM.

  We are happy to answer questions or discuss whether this could be a
  good fit.


[https://github.com/openvstorage/alba]
<https://github.com/openvstorage/alba>

[https://github.com/openvstorage/arakoon]
<https://github.com/openvstorage/arakoon>


Grace 0.3.0 💅, fancy diagnostics library for compilers
═══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-grace-0-3-0-fancy-diagnostics-library-for-compilers/17833/1>


"Alistair O'Brien" announced
────────────────────────────

  I’m excited to announce the release of [grace 0.3.0], an OCaml library
  for building, reporting and rendering beautiful compiler diagnostics
  :camel: :paintbrush:. Now available on [opam-repository].

  This release includes:

  • :window: *Windows support*: Grace now works on Windows, a
    long-awaited feature since its 0.1.0 release! :rocket:
  • :keyboard: *TTY auto-detection*: `Grace_ansi_renderer' can now
    automatically configure itself based on whether the output channel
    is a TTY.  New functions: `pr_diagnostic', `epr_diagnostic', and
    `output_diagnostic'.
  • :elephant: *Line elision*: `Grace_ansi_renderer' now elides
    unnecessary lines in diagnostics, producing more focused output.
  • :zero: *Zero-width ranges*: `Grace_ansi_renderer' can now handle
    zero-width ranges within lines, as well as at end-of-line (EOL) and
    end-of-file (EOF) positions.

  Many thanks to @giltho for their contributions to this release!
  :flexed_biceps:


[grace 0.3.0] <https://github.com/johnyob/grace/releases/tag/0.3.0>

[opam-repository] <https://github.com/ocaml/opam-repository/pull/29379>

CHANGES
╌╌╌╌╌╌╌

  • feat(renderer): add breaks in large diagnostics ([#63])
  • feat(renderer): check for tty when rendering ([#60])
  • fix(renderer): off-by-one in `lines_of_labels' ([#65])
  • fix(renderer): create 0-sized segment on empty label range ([#64])
  • fix(renderer): renderer multi-line labels when message is empty
    ([#53])
  • fix(renderer): fix errors that occur with special zero-width
    segments ([#41])
  • fix(renderer): use `Format.pp_infinity' in `Message.to_string' for
    OCaml >5.2 ([#40])
  • refactor!: removes base/core dependency ([#58])


[#63] <https://github.com/johnyob/grace/pull/63>

[#60] <https://github.com/johnyob/grace/pull/60>

[#65] <https://github.com/johnyob/grace/pull/65>

[#64] <https://github.com/johnyob/grace/pull/64>

[#53] <https://github.com/johnyob/grace/pull/53>

[#41] <https://github.com/johnyob/grace/pull/41>

[#40] <https://github.com/johnyob/grace/pull/40>

[#58] <https://github.com/johnyob/grace/pull/58>


BREAKING CHANGE
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Many base/core interfaces from `Grace' have been replaced with
    custom ones.
  • `Source.reader' has been removed. Use `Source.Reader.t' instead.


Js_of_ocaml / Wasm_of_ocaml 6.3
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-js-of-ocaml-wasm-of-ocaml-6-3/17834/1>


Jérôme Vouillon announced
─────────────────────────

  I'm pleased to announce the joint release of js_of_ocaml and
  wasm_of_ocaml 6.3.

  Js_of_ocaml is a compiler from OCaml bytecode to JavaScript. It makes
  it possible to run pure OCaml programs in JavaScript environment like
  browsers and Node.js.

  Wasm_of_ocaml is a compiler from OCaml bytecode to WebAssembly. It is
  highly compatible with Js_of_ocaml, so you can compile your programs
  with wasm_of_ocaml instead of js_of_ocaml and experience overall
  better performance.

  Most significant changes (since 6.1):

  • *Number unboxing for wasm_of_ocaml*: a type analysis pass now tracks
     which values are floats, integers, or nativeints, enabling the
     compiler to unbox them and use native Wasm instructions
     directly. This also enables specialisation of number comparisons
     and bigarray operations, avoiding costly generic runtime calls.
  • *Constant sinking for js_of_ocaml*: a new optimisation pass moves
     constants closer to their use sites, reducing register
     pressure. Many constants end up inlined, resulting in smaller code
     size.
  • *JS parser improvements*: support for import/export attributes,
     decorators, `using' declarations (resource management), and HTML
     comments.
  • Many bug fixes across the compiler, runtime, library bindings, and
    PPX.

  See the [Changelog] for the full list of changes.


[Changelog]
<https://github.com/ocsigen/js_of_ocaml/blob/master/CHANGES.md>


kqueue-ml 0.5.0
═══════════════

  Archive: <https://discuss.ocaml.org/t/ann-kqueue-ml-0-5-0/17835/1>


Anurag Soni announced
─────────────────────

  Hi,

  I'd like to announce a new release for [kqueue-ml version 0.5.0]

  *Kqueue-ml:* Thin bindings to kqueue event notification system.

  Changes since the last release:

  • Moved development to [codeberg]
  • Remove dependencies on `ppx_optcomp' and `ppx_expect' (Dependencies
    are limited to the ocaml standard library and dune)

  Best, Anurag


[kqueue-ml version 0.5.0]
<https://opam.ocaml.org/packages/kqueue/kqueue.0.5.0/>

[codeberg] <https://codeberg.org/anuragsoni/kqueue-ml/>


Dune 3.21.0
═══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-3-21-0/17700/2>


Continuing this thread, Shon announced
──────────────────────────────────────

  The Dune team announces [the release of dune 3.21.1].

  This is a small patch release consisting of a few bug fixes. See [the
  full changelog] for all the changes.

  If you encounter a problem with this release, please report it in [our
  issue tracker].


[the release of dune 3.21.1]
<https://github.com/ocaml/dune/releases/tag/3.21.1>

[the full changelog] <https://github.com/ocaml/dune/releases/tag/3.21.1>

[our issue tracker] <https://github.com/ocaml/dune/issues>


Other OCaml News
════════════════

From the ocaml.org blog
───────────────────────

  Here are links from many OCaml blogs aggregated at [the ocaml.org
  blog].

  • [At the AI Impact Summit in Delhi: people, planet, progress]
  • [OBuilder on Windows: Bringing Native Container Builds with the HCS
    Backend]
  • [1st TESSERA/CoRE hackathon at the Indian AI Summit]


[the ocaml.org blog] <https://ocaml.org/blog/>

[At the AI Impact Summit in Delhi: people, planet, progress]
<https://anil.recoil.org/notes/india-ai-summit>

[OBuilder on Windows: Bringing Native Container Builds with the HCS
Backend] <https://www.tunbury.org/2026/02/19/obuilder-hcs/>

[1st TESSERA/CoRE hackathon at the Indian AI Summit]
<https://anil.recoil.org/notes/first-tessera-hackathon>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  to the [caml-list].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[caml-list] <https://sympa.inria.fr/sympa/info/caml-list>

[Alan Schmitt] <https://alan.petitepomme.net/>


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