Swift 6 compliance: @main entry, @MainActor isolation and MetalBuffer safety improvements

SceneDepthPointCloud.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 50;
+	objectVersion = 54;
 	objects = {
 
 /* Begin PBXBuildFile section */
@@ -131,8 +131,9 @@
 		E73DD12524636FEF00D77039 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
+				BuildIndependentTargetsInParallel = YES;
 				LastSwiftUpdateCheck = 1140;
-				LastUpgradeCheck = 1200;
+				LastUpgradeCheck = 2610;
 				ORGANIZATIONNAME = Apple;
 				TargetAttributes = {
 					E73DD12C24636FEF00D77039 = {
@@ -245,8 +246,10 @@
 				CODE_SIGN_STYLE = Automatic;
 				COPY_PHASE_STRIP = NO;
 				DEBUG_INFORMATION_FORMAT = dwarf;
+				DEVELOPMENT_TEAM = 58R9CYQKK2;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
@@ -266,6 +269,7 @@
 				MTL_FAST_MATH = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos.internal;
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 			};
@@ -308,8 +312,10 @@
 				CODE_SIGN_STYLE = Automatic;
 				COPY_PHASE_STRIP = NO;
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
+				DEVELOPMENT_TEAM = 58R9CYQKK2;
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
@@ -322,6 +328,7 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
 				SDKROOT = iphoneos.internal;
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_COMPILATION_MODE = wholemodule;
 				SWIFT_OPTIMIZATION_LEVEL = "-O";
 				VALIDATE_PRODUCT = YES;
@@ -337,8 +344,8 @@
 				CODE_SIGN_IDENTITY = "iPhone Developer";
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
-				DEVELOPMENT_TEAM = 52N826U726;
 				INFOPLIST_FILE = SceneDepthPointCloud/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 26.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -349,7 +356,7 @@
 				PROVISIONING_PROFILE_SPECIFIER = "";
 				SDKROOT = iphoneos;
 				SWIFT_OBJC_BRIDGING_HEADER = "SceneDepthPointCloud/SceneDepthPointCloud-Bridging-Header.h";
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -363,8 +370,8 @@
 				CODE_SIGN_IDENTITY = "iPhone Developer";
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
-				DEVELOPMENT_TEAM = 52N826U726;
 				INFOPLIST_FILE = SceneDepthPointCloud/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 26.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -375,7 +382,7 @@
 				PROVISIONING_PROFILE_SPECIFIER = "";
 				SDKROOT = iphoneos;
 				SWIFT_OBJC_BRIDGING_HEADER = "SceneDepthPointCloud/SceneDepthPointCloud-Bridging-Header.h";
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;

SceneDepthPointCloud.xcodeproj/xcshareddata/xcschemes/SceneDepthPointCloud.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1200"
+   LastUpgradeVersion = "2610"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

SceneDepthPointCloud/AppDelegate.swift

@@ -8,7 +8,7 @@ Contains the application's delegate.
 import UIKit
 import ARKit
 
-@UIApplicationMain
+@main
 class AppDelegate: UIResponder, UIApplicationDelegate {
 
     var window: UIWindow?

SceneDepthPointCloud/MetalBuffer.swift

@@ -43,7 +43,16 @@ struct MetalBuffer<Element>: Resource {
     /// Initializes the buffer with the contents of the provided array.
     init(device: MTLDevice, array: [Element], index: UInt32, options: MTLResourceOptions = []) {
 
-        guard let buffer = device.makeBuffer(bytes: array, length: MemoryLayout<Element>.stride * array.count, options: .storageModeShared) else {
+        // Safely create a buffer from the array's raw bytes. This avoids forming an UnsafeRawPointer
+        // directly from `[Element]` which may contain references.
+        let length = MemoryLayout<Element>.stride * array.count
+        let created: MTLBuffer? = array.withUnsafeBytes { rawBuffer in
+            guard let base = rawBuffer.baseAddress, rawBuffer.count == length else {
+                return device.makeBuffer(length: length, options: options)
+            }
+            return device.makeBuffer(bytes: base, length: rawBuffer.count, options: options)
+        }
+        guard let buffer = created else {
             fatalError("Failed to create MTLBuffer")
         }
         self.buffer = buffer
@@ -60,10 +69,25 @@ struct MetalBuffer<Element>: Resource {
     }
 
     /// Replaces the buffer's memory with the values in the array.
-    func assign<Element>(with array: [Element]) {
+    func assign(with array: [Element]) {
         let byteCount = array.count * stride
         precondition(byteCount == buffer.length, "Mismatch between the byte count of the array's contents and the MTLBuffer length.")
-        buffer.contents().copyMemory(from: array, byteCount: byteCount)
+
+        // Safely copy from the array's raw bytes. Avoid forming an UnsafeRawPointer directly from `[Element]`
+        // because `Element` may contain references.
+        array.withUnsafeBytes { rawBuffer in
+            if let base = rawBuffer.baseAddress, rawBuffer.count == byteCount {
+                buffer.contents().copyMemory(from: base, byteCount: byteCount)
+            } else {
+                // If we cannot get a valid raw representation (e.g., Element contains references),
+                // fall back to per-element assignment to avoid undefined behavior.
+                for i in 0..<array.count {
+                    withUnsafePointer(to: array[i]) { ptr in
+                        buffer.contents().advanced(by: i * stride).copyMemory(from: ptr, byteCount: stride)
+                    }
+                }
+            }
+        }
     }
 
     /// Returns a copy of the value at the specified element index in the buffer.

SceneDepthPointCloud/Renderer.swift

@@ -11,6 +11,7 @@ import ARKit
 import Foundation
 import UIKit
 
+@MainActor
 final class Renderer {
     // Whether recording is on
     public var isRecording = false;
@@ -504,3 +505,4 @@ private extension Renderer {
         return flipYZ * matrix_float4x4(simd_quaternion(rotationAngle, Float3(0, 0, 1)))
     }
 }
+

SceneDepthPointCloud/ViewController.swift

@@ -10,7 +10,8 @@ import Metal
 import MetalKit
 import ARKit
 
-final class ViewController: UIViewController, ARSessionDelegate {
+@MainActor
+final class ViewController: UIViewController, @MainActor ARSessionDelegate {
     private let isUIEnabled = true
     private let confidenceControl = UISegmentedControl(items: ["Low", "Medium", "High"])
     private let rgbRadiusSlider = UISlider()
@@ -215,7 +216,7 @@ final class ViewController: UIViewController, ARSessionDelegate {
 }
 
 // update textlabel on tasks start/finish
-extension ViewController: TaskDelegate {
+extension ViewController: @MainActor TaskDelegate {
     func didStartTask() {
         self.taskNum += 1
         updateTextLabel()
@@ -226,6 +227,7 @@ extension ViewController: TaskDelegate {
         updateTextLabel()
     }
 
+    @MainActor
     private func updateTextLabel() {
         let text = "  1/\(self.renderer.pickFrames)  of new frames  \n  Files saved \(self.completedTaskNum)/\(self.taskNum)  "
         DispatchQueue.main.async {
@@ -250,6 +252,7 @@ extension ViewController: MTKViewDelegate {
 
 // MARK: - RenderDestinationProvider
 
+@MainActor
 protocol RenderDestinationProvider {
     var currentRenderPassDescriptor: MTLRenderPassDescriptor? { get }
     var currentDrawable: CAMetalDrawable? { get }
@@ -258,6 +261,7 @@ protocol RenderDestinationProvider {
     var sampleCount: Int { get set }
 }
 
+@MainActor
 extension MTKView: RenderDestinationProvider {
 
 }