fix: make X-Trace-Sampled also appears if `WithTraceIDResponseHeade…

…r` enabled;

config.go

@@ -10,8 +10,8 @@ import (
 
 // These defaults are used in `TraceHeaderConfig`.
 const (
-	defaultTraceIDResponseHeaderKey      = "X-Trace-Id"
-	defaultTraceSampledResponseHeaderKey = "X-Trace-Sampled"
+	DefaultTraceIDResponseHeaderKey      = "X-Trace-Id"
+	DefaultTraceSampledResponseHeaderKey = "X-Trace-Sampled"
 )
 
 // config is used to configure the mux middleware.
@@ -103,13 +103,14 @@ func WithFilter(filter Filter) Option {
 //
 // Deprecated: use `WithTraceResponseHeaders` instead.
 func WithTraceIDResponseHeader(headerKeyFunc func() string) Option {
-	return optionFunc(func(cfg *config) {
-		if headerKeyFunc == nil {
-			cfg.TraceIDResponseHeaderKey = defaultTraceIDResponseHeaderKey // use default trace header
-		} else {
-			cfg.TraceIDResponseHeaderKey = headerKeyFunc()
-		}
-	})
+	cfg := TraceHeaderConfig{
+		TraceIDHeader:      "",
+		TraceSampledHeader: "",
+	}
+	if headerKeyFunc != nil {
+		cfg.TraceIDHeader = headerKeyFunc()
+	}
+	return WithTraceResponseHeaders(cfg)
 }
 
 // TraceHeaderConfig is configuration for trace headers in the response.
@@ -126,12 +127,12 @@ func WithTraceResponseHeaders(cfg TraceHeaderConfig) Option {
 	return optionFunc(func(c *config) {
 		c.TraceIDResponseHeaderKey = cfg.TraceIDHeader
 		if c.TraceIDResponseHeaderKey == "" {
-			c.TraceIDResponseHeaderKey = defaultTraceIDResponseHeaderKey
+			c.TraceIDResponseHeaderKey = DefaultTraceIDResponseHeaderKey
 		}
 
 		c.TraceSampledResponseHeaderKey = cfg.TraceSampledHeader
 		if c.TraceSampledResponseHeaderKey == "" {
-			c.TraceSampledResponseHeaderKey = defaultTraceSampledResponseHeaderKey
+			c.TraceSampledResponseHeaderKey = DefaultTraceSampledResponseHeaderKey
 		}
 	})
 }

test/cases/sdk_test.go

@@ -425,7 +425,8 @@ func TestSDKIntegrationWithDefaultLegacyHeaderKey(t *testing.T) {
 			),
 		},
 	})
-	require.Equal(t, recordedSpans[0].SpanContext().TraceID().String(), w.Header().Get("X-Trace-ID"))
+	require.Equal(t, recordedSpans[0].SpanContext().TraceID().String(), w.Header().Get(otelchi.DefaultTraceIDResponseHeaderKey))
+	require.Equal(t, "true", w.Header().Get(otelchi.DefaultTraceSampledResponseHeaderKey))
 }
 
 func TestSDKIntegrationWithTraceResponseHeaders(t *testing.T) {
@@ -455,11 +456,11 @@ func TestSDKIntegrationWithTraceResponseHeaders(t *testing.T) {
 			),
 		},
 	})
-	require.Equal(t, recordedSpans[0].SpanContext().TraceID().String(), w.Header().Get("X-Trace-ID"))
-	require.Equal(t, "true", w.Header().Get("X-Trace-Sampled"))
+	require.Equal(t, recordedSpans[0].SpanContext().TraceID().String(), w.Header().Get(otelchi.DefaultTraceIDResponseHeaderKey))
+	require.Equal(t, "true", w.Header().Get(otelchi.DefaultTraceSampledResponseHeaderKey))
 }
 
-func TestSDKIntegrationWithOverrideHeaderKey(t *testing.T) {
+func TestSDKIntegrationWithOverrideLegacyHeaderKey(t *testing.T) {
 	// Define a function inline that transforms the default
 	// header name to a custom header name
 	customHeaderKeyFunc := func() string {
@@ -493,9 +494,10 @@ func TestSDKIntegrationWithOverrideHeaderKey(t *testing.T) {
 		},
 	})
 	require.Equal(t, w.Header().Get(customHeaderKeyFunc()), recordedSpans[0].SpanContext().TraceID().String())
+	require.Equal(t, "true", w.Header().Get(otelchi.DefaultTraceSampledResponseHeaderKey))
 }
 
-func TestSDKIntegrationWithoutOverrideHeaderKey(t *testing.T) {
+func TestSDKIntegrationWithoutOverrideLegacyHeaderKey(t *testing.T) {
 	router, sr := newSDKTestRouter("foobar", true)
 
 	router.HandleFunc("/user/{id:[0-9]+}", ok)
@@ -521,7 +523,8 @@ func TestSDKIntegrationWithoutOverrideHeaderKey(t *testing.T) {
 		},
 	})
 
-	require.Empty(t, w.Header().Get("X-Trace-ID"))
+	require.Empty(t, w.Header().Get(otelchi.DefaultTraceIDResponseHeaderKey))
+	require.Empty(t, w.Header().Get(otelchi.DefaultTraceSampledResponseHeaderKey))
 }
 
 func TestWithPublicEndpoint(t *testing.T) {