Correct the default impl for startAnySpan for 5.7

Sources/Tracing/TracerProtocol+Legacy.swift

@@ -409,15 +409,15 @@ extension TracerProtocol {
     ///   - function: The function name in which the span was started
     ///   - fileID: The `fileID` where the span was started.
     ///   - line: The file line where the span was started.
-    public func startAnySpan(
+    public func startAnySpan<Clock: TracerClock>(
         _ operationName: String,
-        clock: some TracerClock = DefaultTracerClock(),
-        baggage: @autoclosure () -> Baggage = .current ?? .topLevel,
-        ofKind kind: SpanKind = .internal,
-        function: String = #function,
-        file fileID: String = #fileID,
-        line: UInt = #line
-    ) -> any Span {
+        baggage: @autoclosure () -> InstrumentationBaggage.Baggage,
+        ofKind kind: Tracing.SpanKind,
+        clock: Clock,
+        function: String,
+        file fileID: String,
+        line: UInt
+    ) -> Tracing.Span {
         self.startSpan(
             operationName,
             baggage: baggage(),

Tests/TracingTests/TracerTests+swift57.swift

@@ -0,0 +1,134 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Tracing open source project
+//
+// Copyright (c) 2020-2023 Apple Inc. and the Swift Distributed Tracing project
+// authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Instrumentation
+import InstrumentationBaggage
+import Tracing
+import XCTest
+
+#if swift(>=5.7.0)
+// Specifically make sure we don't have to implement startAnySpan
+
+final class SampleSwift57Tracer: TracerProtocol {
+    private(set) var spans = [SampleSwift57Span]()
+    var onEndSpan: (SampleSwift57Span) -> Void = { _ in }
+
+    func startSpan<Clock: TracerClock>(
+        _ operationName: String,
+        baggage: @autoclosure () -> Baggage,
+        ofKind kind: SpanKind,
+        clock: Clock,
+        function: String,
+        file fileID: String,
+        line: UInt
+    ) -> SampleSwift57Span {
+        let span = SampleSwift57Span(
+            operationName: operationName,
+            startTime: clock.now,
+            baggage: baggage(),
+            kind: kind,
+            onEnd: self.onEndSpan
+        )
+        self.spans.append(span)
+        return span
+    }
+
+    public func forceFlush() {}
+
+    func extract<Carrier, Extract>(_ carrier: Carrier, into baggage: inout Baggage, using extractor: Extract)
+        where
+        Extract: Extractor,
+        Carrier == Extract.Carrier
+    {}
+
+    func inject<Carrier, Inject>(_ baggage: Baggage, into carrier: inout Carrier, using injector: Inject)
+        where
+        Inject: Injector,
+        Carrier == Inject.Carrier
+    {}
+}
+
+/// Only intended to be used in single-threaded SampleSwift57ing.
+final class SampleSwift57Span: Span {
+    private let kind: SpanKind
+
+    private var status: SpanStatus?
+
+    public let startTime: UInt64
+    public private(set) var endTime: UInt64?
+
+    private(set) var recordedErrors: [(Error, SpanAttributes)] = []
+
+    var operationName: String
+    let baggage: Baggage
+
+    private(set) var events = [SpanEvent]() {
+        didSet {
+            self.isRecording = !self.events.isEmpty
+        }
+    }
+
+    private(set) var links = [SpanLink]()
+
+    var attributes: SpanAttributes = [:] {
+        didSet {
+            self.isRecording = !self.attributes.isEmpty
+        }
+    }
+
+    private(set) var isRecording = false
+
+    let onEnd: (SampleSwift57Span) -> Void
+
+    init<Instant: TracerInstantProtocol>(
+        operationName: String,
+        startTime: Instant,
+        baggage: Baggage,
+        kind: SpanKind,
+        onEnd: @escaping (SampleSwift57Span) -> Void
+    ) {
+        self.operationName = operationName
+        self.startTime = startTime.millisecondsSinceEpoch
+        self.baggage = baggage
+        self.onEnd = onEnd
+        self.kind = kind
+    }
+
+    func setStatus(_ status: SpanStatus) {
+        self.status = status
+        self.isRecording = true
+    }
+
+    func addLink(_ link: SpanLink) {
+        self.links.append(link)
+    }
+
+    func addEvent(_ event: SpanEvent) {
+        self.events.append(event)
+    }
+
+    func recordError(_ error: Error, attributes: SpanAttributes) {
+        self.recordedErrors.append((error, attributes))
+    }
+
+    func end<Clock: TracerClock>(clock: Clock) {
+        self.endTime = clock.now.millisecondsSinceEpoch
+        self.onEnd(self)
+    }
+}
+
+extension SampleSwift57Tracer: @unchecked Sendable {} // only intended for single threaded SampleSwift57ing
+extension SampleSwift57Span: @unchecked Sendable {} // only intended for single threaded SampleSwift57ing
+
+#endif