From 74022be198be41ac9f0f0686753065ea1b7ba2fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rapha=C3=ABl=20Proust?=
 <raphael-proust@users.noreply.github.com>
Date: Fri, 13 Mar 2026 20:17:09 +0100
Subject: [PATCH] compatibility with lwt 6 (#128)

* compatibility with lwt 6

* try to work for lwt 5 and lwt 6

* CI: try lwt 5 then lwt 6

* only try lwt 6 on OCaml >= 5

* relax lwt bounds

* more robust dune rule

* CI

---------

Co-authored-by: Simon Cruanes <simon.cruanes.2007@m4x.org>
---
 .github/workflows/main.yml     |  9 ++++++---
 src/client/lwt/dune            | 16 ++++++++++++++++
 src/client/lwt/notifier_lwt.ml |  2 +-
 src/client/lwt/types_.ml.5     |  2 ++
 src/client/lwt/types_.ml.6     |  2 ++
 5 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 src/client/lwt/types_.ml.5
 create mode 100644 src/client/lwt/types_.ml.6

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index bdb87e16..53aa0b0b 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -42,10 +42,8 @@ jobs:
           allow-prerelease-opam: true
 
       - run: |
-          opam pin trace https://github.com/ocaml-tracing/ocaml-trace.git#main -y -n
-          opam pin https://github.com/ocaml-tracing/ambient-context.git#HEAD -y -n
           opam install pbrt.4.0 -y
-          opam install ambient-context
+          opam install ambient-context lwt.5.9.2
 
       # We cannot install packages that need eio on ocaml versions before 5
       - run: |
@@ -62,6 +60,11 @@ jobs:
       - run: opam install trace
       - run: opam exec -- dune build @install -p opentelemetry
 
+      - run: opam install lwt.6.1.1 -y
+        if: ${{ matrix.ocaml-compiler == '5.3.x' }}
+      - run: opam exec -- dune build @install -p opentelemetry,opentelemetry-client,opentelemetry-lwt,opentelemetry-client-cohttp-lwt
+        if: ${{ matrix.ocaml-compiler == '5.3.x' }}
+
       - run: opam install ocaml-protoc
       - run: opam exec -- dune build @lint
 
diff --git a/src/client/lwt/dune b/src/client/lwt/dune
index e5e2bdfb..be9e6d1c 100644
--- a/src/client/lwt/dune
+++ b/src/client/lwt/dune
@@ -25,3 +25,19 @@
   mtime.clock.os
   lwt.unix)
  (synopsis "Lwt-specific helpers for opentelemetry-client"))
+
+(rule
+ (enabled_if
+  (and
+   %{lib-available:lwt}
+   (>= %{version:lwt} 6.0)))
+ (action
+  (copy types_.ml.6 types_.ml)))
+
+(rule
+ (enabled_if
+  (and
+   %{lib-available:lwt}
+   (< %{version:lwt} 6.0)))
+ (action
+  (copy types_.ml.5 types_.ml)))
diff --git a/src/client/lwt/notifier_lwt.ml b/src/client/lwt/notifier_lwt.ml
index 1e61a124..c9a241aa 100644
--- a/src/client/lwt/notifier_lwt.ml
+++ b/src/client/lwt/notifier_lwt.ml
@@ -5,7 +5,7 @@ module IO = Io_lwt
 type t = {
   notified: bool Atomic.t;
   cond: unit Lwt_condition.t;
-  notification: int;
+  notification: Types_.notification;
   lwt_tid: int;  (** thread ID where lwt runs *)
   deleted: bool Atomic.t;
 }
diff --git a/src/client/lwt/types_.ml.5 b/src/client/lwt/types_.ml.5
new file mode 100644
index 00000000..c34ffc81
--- /dev/null
+++ b/src/client/lwt/types_.ml.5
@@ -0,0 +1,2 @@
+
+type notification = int
diff --git a/src/client/lwt/types_.ml.6 b/src/client/lwt/types_.ml.6
new file mode 100644
index 00000000..bff82f73
--- /dev/null
+++ b/src/client/lwt/types_.ml.6
@@ -0,0 +1,2 @@
+
+type notification = Lwt_unix.notification