Handle missing sample flag as empty trace flags

Sources/OpenTelemetryXRay/Propagator.swift

@@ -73,14 +73,11 @@ public struct XRayPropagator: OTelPropagator {
         guard let traceID = extractedTraceID else {
             throw TraceHeaderParsingError(value: tracingHeader, reason: .missingTraceID)
         }
-        guard let traceFlags = extractedTraceFlags else {
-            throw TraceHeaderParsingError(value: tracingHeader, reason: .missingSampleDecision)
-        }
 
         return OTel.SpanContext(
             traceID: traceID,
             spanID: spanID ?? OTel.SpanID(bytes: (0, 0, 0, 0, 0, 0, 0, 0)),
-            traceFlags: traceFlags,
+            traceFlags: extractedTraceFlags ?? [],
             isRemote: true
         )
     }
@@ -148,7 +145,5 @@ extension XRayPropagator.TraceHeaderParsingError {
         case invalidTraceIDDelimiters
 
         case invalidSpanIDLength(Int)
-
-        case missingSampleDecision
     }
 }

Tests/OpenTelemetryXRayTests/PropagatorTests.swift

@@ -125,14 +125,16 @@ final class XRayPropagatorTests: XCTestCase {
         )
     }
 
-    func test_extractFails_missingSampleDecision() throws {
+    func test_extractsTracingHeader_missingSampleDecision() throws {
         let tracingHeader = "Root=1-5759e988-bd862e3fe1be46a994272793;Parent=53995c3f42cd8ad8"
         let headers = ["X-Amzn-Trace-Id": tracingHeader]
 
-        XCTAssertThrowsError(
-            try propagator.extractSpanContext(from: headers, using: extractor),
-            XRayPropagator.TraceHeaderParsingError(value: tracingHeader, reason: .missingSampleDecision)
-        )
+        let spanContext = try XCTUnwrap(propagator.extractSpanContext(from: headers, using: extractor))
+
+        XCTAssertEqual(spanContext.traceID.description, "5759e988bd862e3fe1be46a994272793")
+        XCTAssertEqual(spanContext.spanID.description, "53995c3f42cd8ad8")
+        XCTAssertTrue(spanContext.traceFlags.isEmpty)
+        XCTAssertNil(spanContext.traceState)
     }
 
     func test_extractFails_invalidTraceIDLength() throws {