fix remaining warnings & enable -warnings-as-errors in CI

.github/workflows/main.yml

@@ -14,8 +14,8 @@ jobs:
     with:
       linux_5_9_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
       linux_5_10_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
-      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error"
-      linux_nightly_6_0_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_6_0_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
+      linux_nightly_6_0_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
       linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
 
   cxx-interop:

Sources/NIOFoundationCompat/ByteBuffer-foundation.swift

@@ -377,15 +377,9 @@ extension ByteBufferAllocator {
 }
 
 // MARK: - Conformances
-#if compiler(>=6.0)
-extension ByteBufferView: @retroactive ContiguousBytes {}
-extension ByteBufferView: @retroactive DataProtocol {}
-extension ByteBufferView: @retroactive MutableDataProtocol {}
-#else
 extension ByteBufferView: ContiguousBytes {}
 extension ByteBufferView: DataProtocol {}
 extension ByteBufferView: MutableDataProtocol {}
-#endif
 
 extension ByteBufferView {
     public typealias Regions = CollectionOfOne<ByteBufferView>

Tests/NIOPosixTests/EchoServerClientTest.swift

@@ -224,7 +224,7 @@ class EchoServerClientTest: XCTestCase {
 
         try withTemporaryUnixDomainSocketPathName { udsPath in
             // Bootstrap should not overwrite an existing file unless it is a socket
-            FileManager.default.createFile(atPath: udsPath, contents: nil, attributes: nil)
+            _ = FileManager.default.createFile(atPath: udsPath, contents: nil, attributes: nil)
             let bootstrap = ServerBootstrap(group: group)
 
             XCTAssertThrowsError(

Tests/NIOPosixTests/NIOThreadPoolTest.swift

@@ -78,18 +78,15 @@ class NIOThreadPoolTest: XCTestCase {
 
         // The lock here is arguably redundant with the dispatchgroup, but let's make
         // this test thread-safe even if I screw up.
-        let lock = NIOLock()
-        let threadOne: NIOLockedValueBox<Thread?> = NIOLockedValueBox(Thread?.none)
-        let threadTwo: NIOLockedValueBox<Thread?> = NIOLockedValueBox(Thread?.none)
+        let threadOne: NIOLockedValueBox<NIOThread?> = NIOLockedValueBox(NIOThread?.none)
+        let threadTwo: NIOLockedValueBox<NIOThread?> = NIOLockedValueBox(NIOThread?.none)
 
         completionGroup.enter()
         pool.submit { s in
             precondition(s == .active)
-            lock.withLock { () -> Void in
-                threadOne.withLockedValue { threadOne in
-                    XCTAssertEqual(threadOne, nil)
-                    threadOne = Thread.current
-                }
+            threadOne.withLockedValue { threadOne in
+                XCTAssertEqual(threadOne, nil)
+                threadOne = NIOThread.current
             }
             completionGroup.leave()
         }
@@ -99,22 +96,18 @@ class NIOThreadPoolTest: XCTestCase {
         completionGroup.enter()
         pool.submit { s in
             precondition(s == .active)
-            lock.withLock { () -> Void in
-                threadTwo.withLockedValue { threadTwo in
-                    XCTAssertEqual(threadTwo, nil)
-                    threadTwo = Thread.current
-                }
+            threadTwo.withLockedValue { threadTwo in
+                XCTAssertEqual(threadTwo, nil)
+                threadTwo = NIOThread.current
             }
             completionGroup.leave()
         }
 
         completionGroup.wait()
 
-        lock.withLock { () -> Void in
-            XCTAssertNotNil(threadOne)
-            XCTAssertNotNil(threadTwo)
-            XCTAssertEqual(threadOne.withLockedValue { $0 }, threadTwo.withLockedValue { $0 })
-        }
+        XCTAssertNotNil(threadOne.withLockedValue { $0 })
+        XCTAssertNotNil(threadTwo.withLockedValue { $0 })
+        XCTAssertEqual(threadOne.withLockedValue { $0 }, threadTwo.withLockedValue { $0 })
     }
 
     func testAsyncThreadPool() async throws {

Tests/NIOPosixTests/SALEventLoopTests.swift

@@ -59,16 +59,12 @@ final class SALEventLoopTests: XCTestCase, SALTest {
                 }
 
                 // Now execute 10 tasks.
-                var i = 0
                 for _ in 0..<10 {
-                    thisLoop.execute {
-                        i &+= 1
-                    }
+                    thisLoop.execute {}
                 }
 
                 // Now enqueue a "last" task.
                 thisLoop.execute {
-                    i &+= 1
                     promise.succeed(())
                 }
 

Tests/NIOPosixTests/TestUtils.swift

@@ -127,7 +127,7 @@ func withTemporaryUnixDomainSocketPathName<T>(
         shortEnoughPath = path
         restoreSavedCWD = false
     } catch SocketAddressError.unixDomainSocketPathTooLong {
-        FileManager.default.changeCurrentDirectoryPath(
+        _ = FileManager.default.changeCurrentDirectoryPath(
             URL(fileURLWithPath: path).deletingLastPathComponent().absoluteString
         )
         shortEnoughPath = URL(fileURLWithPath: path).lastPathComponent
@@ -141,7 +141,7 @@ func withTemporaryUnixDomainSocketPathName<T>(
             try? FileManager.default.removeItem(atPath: path)
         }
         if restoreSavedCWD {
-            FileManager.default.changeCurrentDirectoryPath(saveCurrentDirectory)
+            _ = FileManager.default.changeCurrentDirectoryPath(saveCurrentDirectory)
         }
     }
     return try body(shortEnoughPath)