fix: critical bugs found in code review

Bug #1: Fix worker count logic in generic_consumer
- Was: min 2 (max 500 n_workers) - always created 2 workers
- Now: max 2 (min 500 n_workers) - properly clamps between 2-500
- Impact: Worker configuration was completely ignored

Bug #2: Handle missing dot in __FUNCTION__ name
- Added exception handling for String.rindex in trace span creation
- Prevents crash when tracing top-level or non-module functions
- Uses option type for module_path when no dot is present
- Scoped try/catch to only parsing logic

src/client/generic_consumer.ml

@@ -194,7 +194,7 @@ end = struct
     in
 
     (* start workers *)
-    let n_workers = min 2 (max 500 self.config.n_workers) in
+    let n_workers = max 2 (min 500 self.config.n_workers) in
 
     ignore (Atomic.fetch_and_add self.n_workers n_workers : int);
     for _i = 1 to n_workers do

src/trace/opentelemetry_trace.ml

@@ -71,17 +71,27 @@ open struct
     (* add more data if [__FUNCTION__] is present *)
     (match __FUNCTION__ with
     | Some __FUNCTION__ when OTEL.Span.is_not_dummy otel_sp ->
+      let function_name, module_path =
+        try
           let last_dot = String.rindex __FUNCTION__ '.' in
           let module_path = String.sub __FUNCTION__ 0 last_dot in
           let function_name =
             String.sub __FUNCTION__ (last_dot + 1)
               (String.length __FUNCTION__ - last_dot - 1)
           in
-      OTEL.Span.add_attrs otel_sp
-        [
-          "code.function", `String function_name;
-          "code.namespace", `String module_path;
-        ]
+          function_name, Some module_path
+        with Not_found ->
+          (* __FUNCTION__ has no dot, use it as-is *)
+          __FUNCTION__, None
+      in
+      let attrs =
+        ("code.function", `String function_name)
+        ::
+        (match module_path with
+        | Some module_path -> [ "code.namespace", `String module_path ]
+        | None -> [])
+      in
+      OTEL.Span.add_attrs otel_sp attrs
     | _ -> ());
 
     Span_otel otel_sp

tests/implicit_scope/sync/dune

@@ -1,4 +1,9 @@
 (tests
  (names test_implicit_scope_sync)
  (package opentelemetry-client-cohttp-lwt)
- (libraries threads alcotest opentelemetry unix opentelemetry-client-cohttp-lwt))
+ (libraries
+  threads
+  alcotest
+  opentelemetry
+  unix
+  opentelemetry-client-cohttp-lwt))