From 18226a63a4f235598fd979b3f2461ae08e7979f8 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 10 Dec 2025 14:37:30 -0500
Subject: [PATCH] add Span.dummy

---
 src/core/span.ml  | 11 +++++++++--
 src/core/span.mli |  3 +++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/core/span.ml b/src/core/span.ml
index 86f3826e..adbf3be8 100644
--- a/src/core/span.ml
+++ b/src/core/span.ml
@@ -44,6 +44,12 @@ let make ?(kind = !default_kind) ?trace_state ?(attrs = []) ?(events = [])
   in
   span
 
+let dummy : t =
+  Proto.Trace.make_span
+    ~trace_id:Trace_id.(dummy |> to_bytes)
+    ~span_id:Span_id.(dummy |> to_bytes)
+    ()
+
 let create_new ?kind ?(id = Span_id.create ()) ?trace_state ?attrs ?events
     ?status ~trace_id ?parent ?links ~start_time ~end_time name : t =
   make ?kind ~id ~trace_id ?trace_state ?attrs ?events ?status ?parent ?links
@@ -84,7 +90,8 @@ let[@inline] to_span_ctx (self : t) : Span_ctx.t =
 let[@inline] add_event self ev : unit =
   if is_not_dummy self then span_set_events self (ev :: self.events)
 
-let add_event' self ev : unit = if is_not_dummy self then add_event self (ev ())
+let add_event' self ev : unit =
+  if is_not_dummy self then span_set_events self (ev () :: self.events)
 
 let record_exception (self : t) (exn : exn) (bt : Printexc.raw_backtrace) : unit
     =
@@ -117,7 +124,7 @@ let add_attrs' (self : t) (attrs : unit -> Key_value.t list) : unit =
   )
 
 let add_links (self : t) (links : Span_link.t list) : unit =
-  if links <> [] then (
+  if is_not_dummy self && links <> [] then (
     let links = List.rev_append links self.links in
     span_set_links self links
   )
diff --git a/src/core/span.mli b/src/core/span.mli
index 0cd9478b..793b8ce1 100644
--- a/src/core/span.mli
+++ b/src/core/span.mli
@@ -51,6 +51,9 @@ val trace_id : t -> Trace_id.t
 
 val is_not_dummy : t -> bool
 
+val dummy : t
+(** Dummy span, will not record anything *)
+
 val create_new :
   ?kind:kind ->
   ?id:Span_id.t ->