Finally fix Linux stream crashes and logging test timing

- Guard the InputStream/OutputStream throwing helpers against Foundation’s unimplemented streamError on Linux so CC_read/CC_write no longer trigger illegal instructions when the underlying handle is closed; fall back to .unknown while keeping richer errors on Apple platforms.
- Make the async sleep helper in Logging.testRollingTimestamp2 @sendable and switch it to Thread.sleep on Linux so detached threads actually delay, restoring deterministic timestamp gaps and removing the Swift 6 warning.

It looks like there is an open, but (unsurprisingly) abandoned bug entry at swiftlang/swift-corelibs-foundation#3956

Author: mickeyl

Sources/CornucopiaCore/Extensions/InputStream/InputStream+ThrowingRead.swift

@@ -21,7 +21,12 @@ extension InputStream {
         guard nRead > 0 else {
             switch nRead {
                 case 0: throw Exception.eof
-                default: throw self.streamError ?? Exception.unknown
+                default:
+                    #if os(Linux)
+                    throw Exception.unknown
+                    #else
+                    throw self.streamError ?? Exception.unknown
+                    #endif
             }
         }
         return nRead

Sources/CornucopiaCore/Extensions/OutputStream/OutputStream+ThrowingWrite.swift

@@ -20,7 +20,12 @@ extension OutputStream {
         guard nWritten > 0 else {
             switch nWritten {
                 case 0: throw Exception.eof
-                default: throw self.streamError ?? Exception.unknown
+                default:
+                    #if os(Linux)
+                    throw Exception.unknown
+                    #else
+                    throw self.streamError ?? Exception.unknown
+                    #endif
             }
         }
         return nWritten

Tests/CornucopiaCoreTests/Logging/LogFile.swift

@@ -118,11 +118,15 @@ class Logging: XCTestCase {
 
     func testRollingTimestamp2() throws {
 
-        func sleep(forTimeInterval t: TimeInterval) {
+        @Sendable func sleep(forTimeInterval t: TimeInterval) {
+            #if os(Linux)
+            Thread.sleep(forTimeInterval: t)
+            #else
             let sema = DispatchSemaphore(value: 0)
             let t = Timer(timeInterval: t, repeats: false) { _ in sema.signal() }
             RunLoop.main.add(t, forMode: .common)
             sema.wait()
+            #endif
         }
 
         let path = "/tmp/logging-test/timestamps2.txt"