fix API, always require Baggage, people should pass .topLevel

Author: ktoso

Sources/Tracing/Tracer.swift

@@ -166,11 +166,11 @@ extension Tracer {
     /// - Throws: the error the `operation` has thrown (if any)
     public func withSpan<T>(
         _ operationName: String,
-        baggage: Baggage?,
+        baggage: Baggage,
         ofKind kind: SpanKind = .internal,
         _ operation: (Span) async throws -> T
     ) async rethrows -> T {
-        let span = self.startSpan(operationName, baggage: baggage ?? .topLevel, ofKind: kind)
+        let span = self.startSpan(operationName, baggage: baggage, ofKind: kind)
         defer { span.end() }
         do {
             return try await Baggage.$current.withValue(span.baggage) {

Tests/TracingTests/TracerTests+XCTest.swift

@@ -33,6 +33,7 @@ extension TracerTests {
                 ("testWithSpan_automaticBaggagePropagation_sync", testWithSpan_automaticBaggagePropagation_sync),
                 ("testWithSpan_automaticBaggagePropagation_sync_throws", testWithSpan_automaticBaggagePropagation_sync_throws),
                 ("testWithSpan_automaticBaggagePropagation_async", testWithSpan_automaticBaggagePropagation_async),
+                ("testWithSpan_enterFromNonAsyncCode_passBaggage_asyncOperation", testWithSpan_enterFromNonAsyncCode_passBaggage_asyncOperation),
                 ("testWithSpan_automaticBaggagePropagation_async_throws", testWithSpan_automaticBaggagePropagation_async_throws),
            ]
    }

Tests/TracingTests/TracerTests.swift

@@ -188,7 +188,7 @@ final class TracerTests: XCTestCase {
     }
 
 
-    func testWithSpan_enterFromNonAsyncCode_passBaggage_asyncOperation() async throws {
+    func testWithSpan_enterFromNonAsyncCode_passBaggage_asyncOperation() throws {
         #if swift(>=5.5) && canImport(_Concurrency)
         guard #available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *) else {
             throw XCTSkip("Task locals are not supported on this platform.")
@@ -207,16 +207,18 @@ final class TracerTests: XCTestCase {
             "world"
         }
 
-        var fromNonAsyncWorld = Baggage.topLevel
-        fromNonAsyncWorld.traceID = "1234-5678"
-        let value = await tracer.withSpan("hello", baggage: fromNonAsyncWorld) { (span: Span) -> String in
-            XCTAssertEqual(span.baggage.traceID, Baggage.current?.traceID)
-            XCTAssertEqual(span.baggage.traceID, fromNonAsyncWorld.traceID)
-            return await operation(span: span)
-        }
+        self.testAsync {
+            var fromNonAsyncWorld = Baggage.topLevel
+            fromNonAsyncWorld.traceID = "1234-5678"
+            let value = await tracer.withSpan("hello", baggage: fromNonAsyncWorld) { (span: Span) -> String in
+                XCTAssertEqual(span.baggage.traceID, Baggage.current?.traceID)
+                XCTAssertEqual(span.baggage.traceID, fromNonAsyncWorld.traceID)
+                return await operation(span: span)
+            }
 
-        XCTAssertEqual(value, "world")
-        XCTAssertTrue(spanEnded)
+            XCTAssertEqual(value, "world")
+            XCTAssertTrue(spanEnded)
+        }
         #endif
     }