Mark types Sendable

Sources/Instrumentation/Instrument.swift

@@ -14,10 +14,21 @@
 
 import InstrumentationBaggage
 
+/// Typealias used to simplify Support of old Swift versions which do not have `Sendable` defined.
+#if swift(>=5.6.0)
+@preconcurrency public protocol _SwiftInstrumentationSendable: Sendable {}
+#else
+public protocol _SwiftInstrumentationSendable {}
+#endif
+
 /// Conforming types are used to extract values from a specific `Carrier`.
-public protocol Extractor {
+public protocol Extractor: _SwiftInstrumentationSendable {
     /// The carrier to extract values from.
+    #if swift(>=5.6.0)
+    associatedtype Carrier: Sendable
+    #else
     associatedtype Carrier
+    #endif
 
     /// Extract the value for the given key from the `Carrier`.
     ///
@@ -28,9 +39,13 @@ public protocol Extractor {
 }
 
 /// Conforming types are used to inject values into a specific `Carrier`.
-public protocol Injector {
+public protocol Injector: _SwiftInstrumentationSendable {
     /// The carrier to inject values into.
+    #if swift(>=5.6.0)
+    associatedtype Carrier: Sendable
+    #else
     associatedtype Carrier
+    #endif
 
     /// Inject the given value for the given key into the given `Carrier`.
     ///
@@ -43,7 +58,7 @@ public protocol Injector {
 
 /// Conforming types are usually cross-cutting tools like tracers. They are agnostic of what specific `Carrier` is used
 /// to propagate metadata across boundaries, but instead just specify what values to use for which keys.
-public protocol Instrument {
+public protocol Instrument: _SwiftInstrumentationSendable {
     /// Extract values from a `Carrier` by using the given extractor and inject them into the given `Baggage`.
     /// It's quite common for `Instrument`s to come up with new values if they weren't passed along in the given `Carrier`.
     ///

Sources/Tracing/Span.swift

@@ -22,7 +22,7 @@ import Dispatch
 /// Creating a `Span` is delegated to a ``Tracer`` and end users should never create them directly.
 ///
 /// - SeeAlso: For more details refer to the [OpenTelemetry Specification: Span](https://github.com/open-telemetry/opentelemetry-specification/blob/v0.7.0/specification/trace/api.md#span) which this type is compatible with.
-public protocol Span: AnyObject {
+public protocol Span: AnyObject, _SwiftTracingSendableSpan {
     /// The read-only `Baggage` of this `Span`, set when starting this `Span`.
     var baggage: Baggage { get }
 
@@ -650,10 +650,26 @@ public struct SpanLink {
 
     /// Create a new `SpanLink`.
     /// - Parameters:
-    ///   - context: The `Baggage` identifying the targeted ``Span``.
+    ///   - baggage: The `Baggage` identifying the targeted ``Span``.
     ///   - attributes: ``SpanAttributes`` that further describe the link. Defaults to no attributes.
     public init(baggage: Baggage, attributes: SpanAttributes = [:]) {
         self.baggage = baggage
         self.attributes = attributes
     }
 }
+
+#if compiler(>=5.6)
+@preconcurrency public protocol _SwiftTracingSendableSpan: Sendable {}
+#else
+public protocol _SwiftTracingSendableSpan {}
+#endif
+
+#if compiler(>=5.6)
+extension SpanAttributes: Sendable {}
+extension SpanAttribute: @unchecked Sendable {}
+extension SpanStatus: Sendable {}
+extension SpanEvent: @unchecked Sendable {} // unchecked because of DispatchWallTime
+extension SpanKind: Sendable {}
+extension SpanStatus.Code: Sendable {}
+extension SpanLink: Sendable {}
+#endif

Tests/TracingTests/DynamicTracepointTracerTests.swift

@@ -104,6 +104,7 @@ final class DynamicTracepointTracerTests: XCTestCase {
     }
 }
 
+/// Only intended to be used in single-threaded testing.
 final class DynamicTracepointTestTracer: Tracer {
     private(set) var activeTracepoints: Set<TracepointID> = []
 
@@ -227,6 +228,7 @@ final class DynamicTracepointTestTracer: Tracer {
 }
 
 extension DynamicTracepointTestTracer {
+    /// Only intended to be used in single-threaded testing.
     final class TracepointSpan: Tracing.Span {
         private let operationName: String
         private let kind: SpanKind
@@ -288,3 +290,8 @@ extension DynamicTracepointTestTracer {
         }
     }
 }
+
+#if compiler(>=5.6.0)
+extension DynamicTracepointTestTracer: @unchecked Sendable {}
+extension DynamicTracepointTestTracer.TracepointSpan: @unchecked Sendable {}
+#endif

Tests/TracingTests/TestTracer.swift

@@ -18,6 +18,7 @@ import Instrumentation
 import InstrumentationBaggage
 import Tracing
 
+/// Only intended to be used in single-threaded testing.
 final class TestTracer: Tracer {
     private(set) var spans = [TestSpan]()
     var onEndSpan: (Span) -> Void = { _ in }
@@ -93,6 +94,7 @@ extension Baggage {
     }
 }
 
+/// Only intended to be used in single-threaded testing.
 final class TestSpan: Span {
     private let operationName: String
     private let kind: SpanKind
@@ -156,3 +158,8 @@ final class TestSpan: Span {
         self.onEnd(self)
     }
 }
+
+#if compiler(>=5.6.0)
+extension TestTracer: @unchecked Sendable {}
+extension TestSpan: @unchecked Sendable {}
+#endif

Tests/TracingTests/TracedLockTests.swift

@@ -58,6 +58,7 @@ enum TaskIDKey: BaggageKey {
 // ==== ------------------------------------------------------------------------
 // MARK: PrintLn Tracer
 
+/// Only intended to be used in single-threaded testing.
 private final class TracedLockPrintlnTracer: Tracer {
     func startSpan(
         _ operationName: String,
@@ -158,3 +159,8 @@ private final class TracedLockPrintlnTracer: Tracer {
         }
     }
 }
+
+#if compiler(>=5.6.0)
+extension TracedLockPrintlnTracer: Sendable {}
+extension TracedLockPrintlnTracer.TracedLockPrintlnSpan: @unchecked Sendable {}
+#endif