From 842e535147f2ba9ded31e13910cebf615218924d Mon Sep 17 00:00:00 2001
From: Matthew Li <matthew.li@datadoghq.com>
Date: Fri, 25 Sep 2026 15:06:07 -0400
Subject: [PATCH] Add native OTLP export marker to trace chunks

Tag the first span of each chunk with _dd.sdk.otlp_export=false, next to
_dd.tags.process, so the backend can tell native-exported spans from spans
that reached it through the datadogreceiver instead of inferring it at
ingest time. PHP has no OTLP trace export, so the value is always false.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
---
 .../client_init_record_span_tags.phpt         |  1 +
 appsec/tests/extension/ddtrace_basic.phpt     |  1 +
 .../extension/rinit_record_span_tags.phpt     |  1 +
 .../rinit_record_span_tags_fail.phpt          |  1 +
 .../extension/rinit_root_span_add_tag.phpt    |  1 +
 appsec/tests/extension/root_span_add_tag.phpt |  4 ++-
 ..._span_add_tag_with_intermediate_spans.phpt |  1 +
 tests/Common/SnapshotTestTrait.php            |  3 ++
 tests/Common/SpanChecker.php                  |  5 +++
 ...stributed_trace_overwrite_active_span.phpt |  2 +-
 tests/ext/extract_server_values.phpt          |  4 ++-
 tests/ext/referrer_extraction_01.phpt         |  4 ++-
 tests/ext/referrer_extraction_02.phpt         |  4 ++-
 tests/ext/referrer_extraction_03.phpt         |  4 ++-
 tests/ext/referrer_extraction_04.phpt         |  4 ++-
 tests/ext/referrer_extraction_05.phpt         |  4 ++-
 .../ext/root_span_url_as_resource_names.phpt  |  4 ++-
 ...ot_span_url_as_resource_names_no_host.phpt |  4 ++-
 .../ext/root_span_url_with_post_no_param.phpt |  4 ++-
 .../root_span_url_with_post_no_param_set.phpt |  4 ++-
 tests/ext/sandbox/dd_dumper.inc               |  2 ++
 .../ext/sandbox/safe_to_string_metadata.phpt  |  2 +-
 tests/ext/sdk_otlp_export_marker.phpt         | 32 +++++++++++++++++++
 tracer/serializer.c                           |  2 ++
 24 files changed, 85 insertions(+), 13 deletions(-)
 create mode 100644 tests/ext/sdk_otlp_export_marker.phpt

diff --git a/appsec/tests/extension/client_init_record_span_tags.phpt b/appsec/tests/extension/client_init_record_span_tags.phpt
index 2e1e78569e3..cac10102fe8 100644
--- a/appsec/tests/extension/client_init_record_span_tags.phpt
+++ b/appsec/tests/extension/client_init_record_span_tags.phpt
@@ -92,6 +92,7 @@ Array
     [_dd.p.dm] => -0
     [_dd.p.tid] => %s
     [_dd.runtime_family] => php
+    [_dd.sdk.otlp_export] => false
     [appsec.event] => true
     [http.endpoint] => /foo
     [http.method] => GET
diff --git a/appsec/tests/extension/ddtrace_basic.phpt b/appsec/tests/extension/ddtrace_basic.phpt
index 68ce30ae31a..e329e66273d 100644
--- a/appsec/tests/extension/ddtrace_basic.phpt
+++ b/appsec/tests/extension/ddtrace_basic.phpt
@@ -105,6 +105,7 @@ Array
 (
     [_dd.p.dm] => -0
     [_dd.p.tid] => %s
+    [_dd.sdk.otlp_export] => false
     [ddappsec] => true
     [runtime-id] => %s
 )
\ No newline at end of file
diff --git a/appsec/tests/extension/rinit_record_span_tags.phpt b/appsec/tests/extension/rinit_record_span_tags.phpt
index d3cfe2642a2..3562a1d81c0 100644
--- a/appsec/tests/extension/rinit_record_span_tags.phpt
+++ b/appsec/tests/extension/rinit_record_span_tags.phpt
@@ -87,6 +87,7 @@ Array
     [_dd.p.dm] => -0
     [_dd.p.tid] => %s
     [_dd.runtime_family] => php
+    [_dd.sdk.otlp_export] => false
     [appsec.event] => true
     [http.endpoint] => /foo
     [http.method] => GET
diff --git a/appsec/tests/extension/rinit_record_span_tags_fail.phpt b/appsec/tests/extension/rinit_record_span_tags_fail.phpt
index 504489b844f..b4160a00ffb 100644
--- a/appsec/tests/extension/rinit_record_span_tags_fail.phpt
+++ b/appsec/tests/extension/rinit_record_span_tags_fail.phpt
@@ -56,5 +56,6 @@ Array
 (
     [_dd.p.dm] => -0
     [_dd.p.tid] => %s
+    [_dd.sdk.otlp_export] => false
     [runtime-id] => %s
 )
\ No newline at end of file
diff --git a/appsec/tests/extension/rinit_root_span_add_tag.phpt b/appsec/tests/extension/rinit_root_span_add_tag.phpt
index 922a31b8705..144575c8478 100644
--- a/appsec/tests/extension/rinit_root_span_add_tag.phpt
+++ b/appsec/tests/extension/rinit_root_span_add_tag.phpt
@@ -62,6 +62,7 @@ Array
 (
     [_dd.p.dm] => -0
     [_dd.p.tid] => %s
+    [_dd.sdk.otlp_export] => false
     [ddappsec] => true
     [env] => staging
     [http.method] => GET
diff --git a/appsec/tests/extension/root_span_add_tag.phpt b/appsec/tests/extension/root_span_add_tag.phpt
index 0448bdc6ac1..3d1b8b72c52 100644
--- a/appsec/tests/extension/root_span_add_tag.phpt
+++ b/appsec/tests/extension/root_span_add_tag.phpt
@@ -47,11 +47,13 @@ array(1) {
     ["type"]=>
     string(3) "cli"
     ["meta"]=>
-    array(4) {
+    array(5) {
       ["_dd.p.dm"]=>
       string(2) "-0"
       ["_dd.p.tid"]=>
       string(16) "%s"
+      ["_dd.sdk.otlp_export"]=>
+      string(5) "false"
       ["after"]=>
       string(9) "root_span"
       ["runtime-id"]=>
diff --git a/appsec/tests/extension/root_span_add_tag_with_intermediate_spans.phpt b/appsec/tests/extension/root_span_add_tag_with_intermediate_spans.phpt
index 18325e0e794..b9a33c28ff5 100644
--- a/appsec/tests/extension/root_span_add_tag_with_intermediate_spans.phpt
+++ b/appsec/tests/extension/root_span_add_tag_with_intermediate_spans.phpt
@@ -72,6 +72,7 @@ Array
     [_dd.p.dm] => -0
     [_dd.p.tid] => %s
     [_dd.runtime_family] => php
+    [_dd.sdk.otlp_export] => false
     [after] => root_span
     [before] => root_span
     [runtime-id] => %s
diff --git a/tests/Common/SnapshotTestTrait.php b/tests/Common/SnapshotTestTrait.php
index feb12737c2d..be61583431b 100644
--- a/tests/Common/SnapshotTestTrait.php
+++ b/tests/Common/SnapshotTestTrait.php
@@ -139,6 +139,9 @@ private function stopAndCompareSnapshotSession(
         if (!in_array('meta._dd.svc_src', $fieldsToIgnore, true)) {
             $fieldsToIgnore[] = 'meta._dd.svc_src';
         }
+        if (!in_array('meta._dd.sdk.otlp_export', $fieldsToIgnore, true)) {
+            $fieldsToIgnore[] = 'meta._dd.sdk.otlp_export';
+        }
         $url = self::$testAgentUrl . '/test/session/snapshot?ignores=' . implode(',', $fieldsToIgnore) .
             '&test_session_token=' . $token;
 
diff --git a/tests/Common/SpanChecker.php b/tests/Common/SpanChecker.php
index 6c7552f34d4..20dd5b22ab5 100644
--- a/tests/Common/SpanChecker.php
+++ b/tests/Common/SpanChecker.php
@@ -88,6 +88,7 @@ public static function dumpSpansGraph(array $spansGraph, int $indent = 0)
             if (isset($span['meta'])) {
                 unset($span['meta']['_dd.p.dm']);
                 unset($span['meta']['_dd.p.tid']);
+                unset($span['meta']['_dd.sdk.otlp_export']);
                 unset($span['meta']['http.client_ip']);
                 foreach ($span['meta'] as $k => $v) {
                     $out .= str_repeat(' ', $indent) . '  ' . $k . ' => ' . $v . "\n";
@@ -490,6 +491,10 @@ function ($key) use ($pattern) {
             if (!isset($expectedTags['runtime-id'])) {
                 unset($filtered['runtime-id']);
             }
+            // Ignore _dd.sdk.otlp_export unless explicitly tested
+            if (!isset($expectedTags['_dd.sdk.otlp_export'])) {
+                unset($filtered['_dd.sdk.otlp_export']);
+            }
             // http.client_ip is present depending on target SAPI and not helpful here to test
             if (!isset($expectedTags['http.client_ip'])) {
                 unset($filtered['http.client_ip']);
diff --git a/tests/ext/distributed_tracing/distributed_trace_overwrite_active_span.phpt b/tests/ext/distributed_tracing/distributed_trace_overwrite_active_span.phpt
index f2e7b34f194..10bc4e9a015 100644
--- a/tests/ext/distributed_tracing/distributed_trace_overwrite_active_span.phpt
+++ b/tests/ext/distributed_tracing/distributed_trace_overwrite_active_span.phpt
@@ -41,7 +41,7 @@ function largeBaseConvert($numString, $fromBase, $toBase)
 
 function dump_spans() {
     foreach (dd_trace_serialize_closed_spans() as $span) {
-        unset($span["meta"]["process_id"], $span["meta"]["runtime-id"], $span["meta"]["_dd.p.dm"], $span["meta"]["_dd.tags.process"]);
+        unset($span["meta"]["process_id"], $span["meta"]["runtime-id"], $span["meta"]["_dd.p.dm"], $span["meta"]["_dd.tags.process"], $span["meta"]["_dd.sdk.otlp_export"]);
         echo "parent: ", $span["parent_id"] ?? 0, ", trace: {$span["trace_id"]}, meta: " . json_encode($span["meta"] ?? []) . "\n";
     }
     return $span;
diff --git a/tests/ext/extract_server_values.phpt b/tests/ext/extract_server_values.phpt
index 05f51ae9a07..69d8ad24e0a 100644
--- a/tests/ext/extract_server_values.phpt
+++ b/tests/ext/extract_server_values.phpt
@@ -31,11 +31,13 @@ var_dump(dd_trace_serialize_closed_spans()[0]["meta"]);
 
 ?>
 --EXPECTF--
-array(5) {
+array(6) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.request.headers.0"]=>
diff --git a/tests/ext/referrer_extraction_01.phpt b/tests/ext/referrer_extraction_01.phpt
index e5dd8112877..6d41422406f 100644
--- a/tests/ext/referrer_extraction_01.phpt
+++ b/tests/ext/referrer_extraction_01.phpt
@@ -18,11 +18,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/referrer_extraction_02.phpt b/tests/ext/referrer_extraction_02.phpt
index b1bd2435941..ce4817172a8 100644
--- a/tests/ext/referrer_extraction_02.phpt
+++ b/tests/ext/referrer_extraction_02.phpt
@@ -18,11 +18,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(9) {
+array(10) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/referrer_extraction_03.phpt b/tests/ext/referrer_extraction_03.phpt
index 466b388c86c..2a0f673213f 100644
--- a/tests/ext/referrer_extraction_03.phpt
+++ b/tests/ext/referrer_extraction_03.phpt
@@ -18,11 +18,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/referrer_extraction_04.phpt b/tests/ext/referrer_extraction_04.phpt
index 18fe177d5a9..181a7684919 100644
--- a/tests/ext/referrer_extraction_04.phpt
+++ b/tests/ext/referrer_extraction_04.phpt
@@ -18,11 +18,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/referrer_extraction_05.phpt b/tests/ext/referrer_extraction_05.phpt
index 85abb9c4484..edb0b56b5b2 100644
--- a/tests/ext/referrer_extraction_05.phpt
+++ b/tests/ext/referrer_extraction_05.phpt
@@ -18,11 +18,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(9) {
+array(10) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/root_span_url_as_resource_names.phpt b/tests/ext/root_span_url_as_resource_names.phpt
index 9840f0d8ac4..6ea6f960276 100644
--- a/tests/ext/root_span_url_as_resource_names.phpt
+++ b/tests/ext/root_span_url_as_resource_names.phpt
@@ -20,11 +20,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/root_span_url_as_resource_names_no_host.phpt b/tests/ext/root_span_url_as_resource_names_no_host.phpt
index eec467b9242..e7aaa05caf1 100644
--- a/tests/ext/root_span_url_as_resource_names_no_host.phpt
+++ b/tests/ext/root_span_url_as_resource_names_no_host.phpt
@@ -19,11 +19,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(8) {
+array(9) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["http.method"]=>
diff --git a/tests/ext/root_span_url_with_post_no_param.phpt b/tests/ext/root_span_url_with_post_no_param.phpt
index 8553f5f4ef0..ee48fa4a2a0 100644
--- a/tests/ext/root_span_url_with_post_no_param.phpt
+++ b/tests/ext/root_span_url_with_post_no_param.phpt
@@ -18,11 +18,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(4) {
+array(5) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["runtime-id"]=>
diff --git a/tests/ext/root_span_url_with_post_no_param_set.phpt b/tests/ext/root_span_url_with_post_no_param_set.phpt
index 21c0c516765..2472ca28fdb 100644
--- a/tests/ext/root_span_url_with_post_no_param_set.phpt
+++ b/tests/ext/root_span_url_with_post_no_param_set.phpt
@@ -17,11 +17,13 @@ $spans = dd_trace_serialize_closed_spans();
 var_dump($spans[0]['meta']);
 ?>
 --EXPECTF--
-array(4) {
+array(5) {
   ["_dd.p.dm"]=>
   string(2) "-0"
   ["_dd.p.tid"]=>
   string(16) "%s"
+  ["_dd.sdk.otlp_export"]=>
+  string(5) "false"
   ["_dd.tags.process"]=>
   string(%d) "%s"
   ["runtime-id"]=>
diff --git a/tests/ext/sandbox/dd_dumper.inc b/tests/ext/sandbox/dd_dumper.inc
index 9558dac9080..add87210a25 100644
--- a/tests/ext/sandbox/dd_dumper.inc
+++ b/tests/ext/sandbox/dd_dumper.inc
@@ -41,6 +41,7 @@ function dd_dump_spans($skipMeta = false)
             echo PHP_EOL;
             unset($span["meta"]["runtime-id"]);
             unset($span["meta"]["_dd.tags.process"]);
+            unset($span["meta"]["_dd.sdk.otlp_export"]);
             foreach ($span['meta'] as $k => $v) {
                 echo str_repeat(' ', $indent) . '  ' . $k . ' => ' . $v . PHP_EOL;
             }
@@ -82,6 +83,7 @@ function dd_clean_spans() {
     foreach ($spans as &$span) {
         if (isset($span['meta'])) {
             unset($span['meta']['_dd.tags.process']);
+            unset($span['meta']['_dd.sdk.otlp_export']);
             if (empty($span['meta'])) {
                 unset($span['meta']);
             }
diff --git a/tests/ext/sandbox/safe_to_string_metadata.phpt b/tests/ext/sandbox/safe_to_string_metadata.phpt
index 0a6cc5c60a4..58efbfa21b2 100644
--- a/tests/ext/sandbox/safe_to_string_metadata.phpt
+++ b/tests/ext/sandbox/safe_to_string_metadata.phpt
@@ -57,7 +57,7 @@ $allTheTypes[0][1] = &$allTheTypes[0];
 call_user_func_array('meta_to_string', $allTheTypes);
 
 list($span) = dd_trace_serialize_closed_spans();
-unset($span['meta']['process_id'], $span['meta']['_dd.tags.process']);
+unset($span['meta']['process_id'], $span['meta']['_dd.tags.process'], $span['meta']['_dd.sdk.otlp_export']);
 $last = -1;
 foreach ($span['meta'] as $key => $value) {
     $index = (int)substr($key, 4);
diff --git a/tests/ext/sdk_otlp_export_marker.phpt b/tests/ext/sdk_otlp_export_marker.phpt
new file mode 100644
index 00000000000..1c04645c8fb
--- /dev/null
+++ b/tests/ext/sdk_otlp_export_marker.phpt
@@ -0,0 +1,32 @@
+--TEST--
+_dd.sdk.otlp_export marker is set to "false" on the first span of each trace chunk only
+--ENV--
+DD_TRACE_GENERATE_ROOT_SPAN=0
+DD_TRACE_AUTO_FLUSH_ENABLED=0
+--FILE--
+<?php
+for ($i = 0; $i < 2; $i++) {
+    \DDTrace\start_trace_span()->name = "root_$i";
+    \DDTrace\start_span()->name = "child_$i";
+    \DDTrace\start_span()->name = "grandchild_$i";
+    \DDTrace\close_span();
+    \DDTrace\close_span();
+    \DDTrace\close_span();
+}
+
+$seen = [];
+foreach (dd_trace_serialize_closed_spans() as $span) {
+    $first = !isset($seen[$span['trace_id']]);
+    $seen[$span['trace_id']] = true;
+    echo ($first ? "first" : "other"), ": ", var_export($span['meta']['_dd.sdk.otlp_export'] ?? null, true), "\n";
+}
+echo count($seen), " chunks\n";
+?>
+--EXPECT--
+first: 'false'
+other: NULL
+other: NULL
+first: 'false'
+other: NULL
+other: NULL
+2 chunks
diff --git a/tracer/serializer.c b/tracer/serializer.c
index e1fc3e71721..d18c29f8179 100644
--- a/tracer/serializer.c
+++ b/tracer/serializer.c
@@ -1573,6 +1573,8 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
     ddog_set_span_duration(rust_span, span->duration);
 
     if (is_first_span) {
+        ddog_add_str_span_meta_str(rust_span, "_dd.sdk.otlp_export", "false");
+
         zend_string *process_tags = datadog_process_tags_get_serialized();
         if (ZSTR_LEN(process_tags)) {
             const char *svc_tag_appendix = NULL;