vendor: update buildkit to 539be170

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/go.opentelemetry.io/otel/propagation/doc.go

@@ -15,9 +15,6 @@
 /*
 Package propagation contains OpenTelemetry context propagators.
 
-This package is currently in a Release Candidate phase. Backwards incompatible changes
-may be introduced prior to v1.0.0, but we believe the current API is ready to stabilize.
-
 OpenTelemetry propagators are used to extract and inject context data from and
 into messages exchanged by applications. The propagator supported by this
 package is the W3C Trace Context encoding

vendor/go.opentelemetry.io/otel/propagation/propagation.go

@@ -40,6 +40,32 @@ type TextMapCarrier interface {
 	// must never be done outside of a new major release.
 }
 
+// MapCarrier is a TextMapCarrier that uses a map held in memory as a storage
+// medium for propagated key-value pairs.
+type MapCarrier map[string]string
+
+// Compile time check that MapCarrier implements the TextMapCarrier.
+var _ TextMapCarrier = MapCarrier{}
+
+// Get returns the value associated with the passed key.
+func (c MapCarrier) Get(key string) string {
+	return c[key]
+}
+
+// Set stores the key-value pair.
+func (c MapCarrier) Set(key, value string) {
+	c[key] = value
+}
+
+// Keys lists the keys stored in this carrier.
+func (c MapCarrier) Keys() []string {
+	keys := make([]string, 0, len(c))
+	for k := range c {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
 // HeaderCarrier adapts http.Header to satisfy the TextMapCarrier interface.
 type HeaderCarrier http.Header
 
@@ -78,7 +104,7 @@ type TextMapPropagator interface {
 	// DO NOT CHANGE: any modification will not be backwards compatible and
 	// must never be done outside of a new major release.
 
-	// Fields returns the keys who's values are set with Inject.
+	// Fields returns the keys whose values are set with Inject.
 	Fields() []string
 	// DO NOT CHANGE: any modification will not be backwards compatible and
 	// must never be done outside of a new major release.

vendor/go.opentelemetry.io/otel/propagation/trace_context.go

@@ -50,7 +50,9 @@ func (tc TraceContext) Inject(ctx context.Context, carrier TextMapCarrier) {
 		return
 	}
 
-	carrier.Set(tracestateHeader, sc.TraceState().String())
+	if ts := sc.TraceState().String(); ts != "" {
+		carrier.Set(tracestateHeader, ts)
+	}
 
 	// Clear all flags other than the trace-context supported sampling bit.
 	flags := sc.TraceFlags() & trace.FlagsSampled