Fix code review findings: trace_flags default, header comment

- Default trace_flags to 0x00 (not-sampled) per W3C Trace Context spec
  when the field is absent, instead of defaulting to kIsSampled
- Remove misleading "HTTP headers" from header doc comment
- Apply clang-format adjustments

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: pratikmankawde

include/xrpl/telemetry/TraceContextPropagator.h

@@ -1,10 +1,9 @@
 #pragma once
 
-/** Utilities for trace context propagation across nodes and HTTP headers.
+/** Utilities for trace context propagation across nodes.
 
-    Provides serialization/deserialization of OTel trace context to/from:
-      - Protocol Buffer TraceContext messages (P2P cross-node propagation)
-      - HTTP headers (W3C Trace Context for RPC)
+    Provides serialization/deserialization of OTel trace context to/from
+    Protocol Buffer TraceContext messages (P2P cross-node propagation).
 
     Only compiled when XRPL_ENABLE_TELEMETRY is defined.
 */
@@ -46,9 +45,11 @@ extractFromProtobuf(protocol::TraceContext const& proto)
     auto const* rawSpanId = reinterpret_cast<std::uint8_t const*>(proto.span_id().data());
     trace::TraceId traceId(opentelemetry::nostd::span<std::uint8_t const, 16>(rawTraceId, 16));
     trace::SpanId spanId(opentelemetry::nostd::span<std::uint8_t const, 8>(rawSpanId, 8));
+    // Default to not-sampled (0x00) per W3C Trace Context spec when
+    // the trace_flags field is absent.
     trace::TraceFlags flags(
         proto.has_trace_flags() ? static_cast<std::uint8_t>(proto.trace_flags())
-                                : trace::TraceFlags::kIsSampled);
+                                : static_cast<std::uint8_t>(0));
 
     trace::SpanContext spanCtx(traceId, spanId, flags, /* remote = */ true);
 

src/tests/libxrpl/telemetry/TraceContextPropagator.cpp

@@ -5,11 +5,11 @@
 #include <xrpl/telemetry/TraceContextPropagator.h>
 
 #include <opentelemetry/context/context.h>
+#include <opentelemetry/nostd/span.h>
+#include <opentelemetry/trace/context.h>
 #include <opentelemetry/trace/default_span.h>
 #include <opentelemetry/trace/span_context.h>
 #include <opentelemetry/trace/trace_flags.h>
-#include <opentelemetry/nostd/span.h>
-#include <opentelemetry/trace/context.h>
 #include <opentelemetry/trace/trace_id.h>
 
 #include <cstring>
@@ -19,22 +19,32 @@ namespace trace = opentelemetry::trace;
 TEST(TraceContextPropagator, round_trip)
 {
     std::uint8_t traceIdBuf[16] = {
-        0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
-        0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10};
-    std::uint8_t spanIdBuf[8] = {
-        0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x11, 0x22};
-
-    trace::TraceId traceId(
-        opentelemetry::nostd::span<const uint8_t, 16>(traceIdBuf, 16));
-    trace::SpanId spanId(
-        opentelemetry::nostd::span<const uint8_t, 8>(spanIdBuf, 8));
+        0x01,
+        0x02,
+        0x03,
+        0x04,
+        0x05,
+        0x06,
+        0x07,
+        0x08,
+        0x09,
+        0x0a,
+        0x0b,
+        0x0c,
+        0x0d,
+        0x0e,
+        0x0f,
+        0x10};
+    std::uint8_t spanIdBuf[8] = {0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x11, 0x22};
+
+    trace::TraceId traceId(opentelemetry::nostd::span<uint8_t const, 16>(traceIdBuf, 16));
+    trace::SpanId spanId(opentelemetry::nostd::span<uint8_t const, 8>(spanIdBuf, 8));
     trace::TraceFlags flags(trace::TraceFlags::kIsSampled);
     trace::SpanContext spanCtx(traceId, spanId, flags, true);
 
     auto ctx = opentelemetry::context::Context{}.SetValue(
         trace::kSpanKey,
-        opentelemetry::nostd::shared_ptr<trace::Span>(
-            new trace::DefaultSpan(spanCtx)));
+        opentelemetry::nostd::shared_ptr<trace::Span>(new trace::DefaultSpan(spanCtx)));
 
     protocol::TraceContext proto;
     xrpl::telemetry::injectToProtobuf(ctx, proto);
@@ -43,14 +53,11 @@ TEST(TraceContextPropagator, round_trip)
     EXPECT_EQ(proto.trace_id().size(), 16u);
     EXPECT_TRUE(proto.has_span_id());
     EXPECT_EQ(proto.span_id().size(), 8u);
-    EXPECT_EQ(
-        proto.trace_flags(),
-        static_cast<uint32_t>(trace::TraceFlags::kIsSampled));
+    EXPECT_EQ(proto.trace_flags(), static_cast<uint32_t>(trace::TraceFlags::kIsSampled));
     EXPECT_EQ(std::memcmp(proto.trace_id().data(), traceIdBuf, 16), 0);
     EXPECT_EQ(std::memcmp(proto.span_id().data(), spanIdBuf, 8), 0);
 
-    auto extractedCtx =
-        xrpl::telemetry::extractFromProtobuf(proto);
+    auto extractedCtx = xrpl::telemetry::extractFromProtobuf(proto);
     auto extractedSpan = trace::GetSpan(extractedCtx);
     ASSERT_NE(extractedSpan, nullptr);
 
@@ -59,8 +66,7 @@ TEST(TraceContextPropagator, round_trip)
     EXPECT_TRUE(extracted.IsRemote());
     EXPECT_EQ(extracted.trace_id(), traceId);
     EXPECT_EQ(extracted.span_id(), spanId);
-    EXPECT_TRUE(
-        extracted.trace_flags().IsSampled());
+    EXPECT_TRUE(extracted.trace_flags().IsSampled());
 }
 
 TEST(TraceContextPropagator, extract_empty_protobuf)
@@ -114,24 +120,20 @@ TEST(TraceContextPropagator, inject_invalid_span)
 
 TEST(TraceContextPropagator, flags_preservation)
 {
-    std::uint8_t traceIdBuf[16] = {
-        1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
+    std::uint8_t traceIdBuf[16] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};
     std::uint8_t spanIdBuf[8] = {1, 2, 3, 4, 5, 6, 7, 8};
 
     // Test with flags NOT sampled (flags = 0)
     trace::TraceFlags flags(0);
     trace::SpanContext spanCtx(
-        trace::TraceId(
-            opentelemetry::nostd::span<const uint8_t, 16>(traceIdBuf, 16)),
-        trace::SpanId(
-            opentelemetry::nostd::span<const uint8_t, 8>(spanIdBuf, 8)),
+        trace::TraceId(opentelemetry::nostd::span<uint8_t const, 16>(traceIdBuf, 16)),
+        trace::SpanId(opentelemetry::nostd::span<uint8_t const, 8>(spanIdBuf, 8)),
         flags,
         true);
 
     auto ctx = opentelemetry::context::Context{}.SetValue(
         trace::kSpanKey,
-        opentelemetry::nostd::shared_ptr<trace::Span>(
-            new trace::DefaultSpan(spanCtx)));
+        opentelemetry::nostd::shared_ptr<trace::Span>(new trace::DefaultSpan(spanCtx)));
 
     protocol::TraceContext proto;
     xrpl::telemetry::injectToProtobuf(ctx, proto);