Sendable Instrument Carriers (#136)

* Remove unnecesarry Sendable wrappers

* Require Injector/Extractor Carrier to be Sendable

---------

Co-authored-by: Konrad `ktoso` Malawski <[email protected]>

Author: slashmo

Sources/Instrumentation/Instrument.swift

@@ -14,13 +14,10 @@
 
 import ServiceContextModule
 
-/// Typealias used to simplify Support of old Swift versions which do not have `Sendable` defined.
-@preconcurrency public protocol _SwiftInstrumentationSendable: Sendable {}
-
 /// Conforming types are used to extract values from a specific `Carrier`.
-public protocol Extractor: _SwiftInstrumentationSendable {
+public protocol Extractor: Sendable {
     /// The carrier to extract values from.
-    associatedtype Carrier
+    associatedtype Carrier: Sendable
 
     /// Extract the value for the given key from the `Carrier`.
     ///
@@ -31,9 +28,9 @@ public protocol Extractor: _SwiftInstrumentationSendable {
 }
 
 /// Conforming types are used to inject values into a specific `Carrier`.
-public protocol Injector: _SwiftInstrumentationSendable {
+public protocol Injector: Sendable {
     /// The carrier to inject values into.
-    associatedtype Carrier
+    associatedtype Carrier: Sendable
 
     /// Inject the given value for the given key into the given `Carrier`.
     ///
@@ -46,7 +43,7 @@ public protocol Injector: _SwiftInstrumentationSendable {
 
 /// 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: _SwiftInstrumentationSendable {
+public protocol Instrument: Sendable {
     /// Extract values from a `Carrier` by using the given extractor and inject them into the given `ServiceContext`.
     /// 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/SpanProtocol.swift

@@ -31,7 +31,7 @@
 /// resource that must be started, accumulate all possible information from the span's duration, and ended exactly once.
 ///
 /// - 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: _SwiftTracingSendableSpan {
+public protocol Span: Sendable {
     /// The read-only `ServiceContext` of this `Span`, set when starting this `Span`.
     var context: ServiceContext { get }
 
@@ -732,8 +732,6 @@ public struct SpanLink {
     }
 }
 
-@preconcurrency public protocol _SwiftTracingSendableSpan: Sendable {}
-
 extension SpanAttributes: Sendable {}
 extension SpanAttribute: Sendable {} // @unchecked because some payloads are CustomStringConvertible
 extension SpanStatus: Sendable {}

Tests/TracingTests/TracedLockTests.swift

@@ -180,7 +180,5 @@ extension TracedLockPrintlnTracer: Tracer {
     }
 }
 
-#if compiler(>=5.6.0)
 extension TracedLockPrintlnTracer: Sendable {}
 extension TracedLockPrintlnTracer.TracedLockPrintlnSpan: @unchecked Sendable {} // only intended for single threaded testing
-#endif