From 1d2519c02ad468c115b36ce62fe8915c97ba3b1e Mon Sep 17 00:00:00 2001
From: Ivana Kellyer <ivana.kellyer@sentry.io>
Date: Thu, 2 Jul 2026 10:00:51 +0200
Subject: [PATCH] fix(tracing): Correctly propagate from NoOpStreamedSpans

---
 sentry_sdk/scope.py                |  8 ++++++--
 sentry_sdk/traces.py               | 16 +++++++--------
 tests/tracing/test_http_headers.py | 32 ++++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/sentry_sdk/scope.py b/sentry_sdk/scope.py
index 4fd22714cf..191d5893c1 100644
--- a/sentry_sdk/scope.py
+++ b/sentry_sdk/scope.py
@@ -1298,7 +1298,6 @@ def start_streamed_span(
         # active span, this is a segment
         if parent_span is None:
             propagation_context = self.get_active_propagation_context()
-
             if is_ignored_span(name, attributes):
                 return NoOpStreamedSpan(
                     scope=self,
@@ -1317,6 +1316,7 @@ def start_streamed_span(
             if sampled is False:
                 return NoOpStreamedSpan(
                     scope=self,
+                    trace_id=propagation_context.trace_id,
                     unsampled_reason=outcome,
                 )
 
@@ -1338,11 +1338,15 @@ def start_streamed_span(
         with new_scope():
             if is_ignored_span(name, attributes):
                 return NoOpStreamedSpan(
+                    trace_id=parent_span.trace_id,
                     unsampled_reason="ignored",
                 )
 
             if isinstance(parent_span, NoOpStreamedSpan):
-                return NoOpStreamedSpan(unsampled_reason=parent_span._unsampled_reason)
+                return NoOpStreamedSpan(
+                    trace_id=parent_span.trace_id,
+                    unsampled_reason=parent_span._unsampled_reason,
+                )
 
             return StreamedSpan(
                 name=name,
diff --git a/sentry_sdk/traces.py b/sentry_sdk/traces.py
index 5ee7e8460b..46f07127fa 100644
--- a/sentry_sdk/traces.py
+++ b/sentry_sdk/traces.py
@@ -610,18 +610,24 @@ def _to_json(self) -> "SpanJSON":
 
 class NoOpStreamedSpan(StreamedSpan):
     __slots__ = (
+        "_trace_id",
+        "_span_id",
         "_finished",
         "_unsampled_reason",
     )
 
     def __init__(
         self,
+        trace_id: "Optional[str]" = None,
         unsampled_reason: "Optional[str]" = None,
         scope: "Optional[sentry_sdk.Scope]" = None,
     ) -> None:
         self._scope = scope  # type: ignore[assignment]
-        self._unsampled_reason = unsampled_reason
 
+        self._trace_id = trace_id
+        self._span_id = None
+
+        self._unsampled_reason = unsampled_reason
         self._finished = False
 
         self._start()
@@ -716,14 +722,6 @@ def name(self, value: str) -> None:
     def active(self) -> bool:
         return True
 
-    @property
-    def span_id(self) -> str:
-        return "0000000000000000"
-
-    @property
-    def trace_id(self) -> str:
-        return "00000000000000000000000000000000"
-
     @property
     def sampled(self) -> "Optional[bool]":
         return False
diff --git a/tests/tracing/test_http_headers.py b/tests/tracing/test_http_headers.py
index 6a8467101e..7957dd38cf 100644
--- a/tests/tracing/test_http_headers.py
+++ b/tests/tracing/test_http_headers.py
@@ -2,6 +2,7 @@
 
 import pytest
 
+import sentry_sdk
 from sentry_sdk.tracing import Transaction
 from sentry_sdk.tracing_utils import extract_sentrytrace_data
 
@@ -26,6 +27,37 @@ def test_to_traceparent(sampled):
         assert parts[2] == "1" if sampled is True else "0"  # sampled
 
 
+@pytest.mark.parametrize("sampled", ["1", "0", ""])
+def test_to_traceparent_span_streaming(sentry_init, sampled):
+    sentry_init(
+        # parent sampling decision takes precedence over traces_sample_rate
+        traces_sample_rate=1.0,
+        _experiments={"trace_lifecycle": "stream"},
+    )
+
+    trace_id = "12312012123120121231201212312012"
+
+    sentry_sdk.traces.continue_trace(
+        {
+            "sentry-trace": f"{trace_id}-b7ad6b7169203331-{sampled}",
+        }
+    )
+
+    with sentry_sdk.traces.start_span(name="/interactions/other-dogs/new-dog") as span:
+        pass
+
+    traceparent = span._to_traceparent()
+
+    parts = traceparent.split("-")
+    assert parts[0] == trace_id
+    assert parts[1] == span.span_id
+    if sampled == "":
+        # we'll sample this since our traces_sample_rate kicks in
+        assert parts[2] == "1"
+    else:
+        assert parts[2] == sampled
+
+
 @pytest.mark.parametrize("sampling_decision", [True, False])
 def test_sentrytrace_extraction(sampling_decision):
     sentrytrace_header = "12312012123120121231201212312012-0415201309082013-{}".format(