From 37c3f962e0d21c7ab029f07c2dfd83c083d40d0d Mon Sep 17 00:00:00 2001
From: Philippe Hausler <phausler@apple.com>
Date: Fri, 18 Aug 2023 12:30:00 -0700
Subject: [PATCH] Rework availability for executor to avoid warnings

---
 Sources/AsyncSequenceValidation/Job.swift  |  2 +-
 Sources/AsyncSequenceValidation/Test.swift | 47 +++++++++++++++++++---
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/Sources/AsyncSequenceValidation/Job.swift b/Sources/AsyncSequenceValidation/Job.swift
index 44dedbc8..461af50d 100644
--- a/Sources/AsyncSequenceValidation/Job.swift
+++ b/Sources/AsyncSequenceValidation/Job.swift
@@ -19,6 +19,6 @@ struct Job: Hashable, @unchecked Sendable {
   }
   
   func execute() {
-    _swiftJobRun(unsafeBitCast(job, to: UnownedJob.self), AsyncSequenceValidationDiagram.Context.executor.asUnownedSerialExecutor())
+    _swiftJobRun(unsafeBitCast(job, to: UnownedJob.self), AsyncSequenceValidationDiagram.Context.unownedExecutor)
   }
 }
diff --git a/Sources/AsyncSequenceValidation/Test.swift b/Sources/AsyncSequenceValidation/Test.swift
index 0275cc11..8dc86832 100644
--- a/Sources/AsyncSequenceValidation/Test.swift
+++ b/Sources/AsyncSequenceValidation/Test.swift
@@ -67,25 +67,62 @@ extension AsyncSequenceValidationDiagram {
   }
   
   struct Context {
+#if swift(<5.9)
     final class ClockExecutor: SerialExecutor {
-      @available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, *)
+      func enqueue(_ job: UnownedJob) {
+        job._runSynchronously(on: self.asUnownedSerialExecutor())
+      }
+
+      func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+        UnownedSerialExecutor(ordinary: self)
+      }
+    }
+    
+    private static let _executor = ClockExecutor()
+    
+    static var unownedExecutor: UnownedSerialExecutor {
+      _executor.asUnownedSerialExecutor()
+    }
+#else
+    @available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, *)
+    final class ClockExecutor_5_9:  SerialExecutor {
       func enqueue(_ job: __owned ExecutorJob) {
         job.runSynchronously(on: asUnownedSerialExecutor())
       }
       
-      @available(*, deprecated) // known deprecation warning
+      func asUnownedSerialExecutor() -> UnownedSerialExecutor {
+        UnownedSerialExecutor(ordinary: self)
+      }
+    }
+    
+    final class ClockExecutor_Pre5_9: SerialExecutor {
+      @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+      @available(*, deprecated, message: "Implement 'enqueue(_: __owned ExecutorJob)' instead")
       func enqueue(_ job: UnownedJob) {
-        job._runSynchronously(on: asUnownedSerialExecutor())
+        job._runSynchronously(on: self.asUnownedSerialExecutor())
       }
-      
+
       func asUnownedSerialExecutor() -> UnownedSerialExecutor {
         UnownedSerialExecutor(ordinary: self)
       }
     }
     
+    private static let _executor: AnyObject = {
+      if #available(macOS 14.0, iOS 17.0, watchOS 10.0, tvOS 17.0, *) {
+        return ClockExecutor_5_9()
+      } else {
+        return ClockExecutor_Pre5_9()
+      }
+    }()
+    
+    static var unownedExecutor: UnownedSerialExecutor {
+      (_executor as! any SerialExecutor).asUnownedSerialExecutor()
+    }
+#endif
+
     static var clock: Clock?
     
-    static let executor = ClockExecutor()
+    
     
     static var driver: TaskDriver?