Compound - Swift 6.2 and Main actor isolation (#5109)

* compound is now using 6.2 and main actor isolation + some tweaks to make it build tests and EX

* better handling of the nonisolated context for CompoundUIColors

* improving docs

* fix comment

* remove unused Sendable conformance

compound-ios/Tests/CompoundTests/AvatarColorsTests.swift

@@ -11,6 +11,7 @@ import Foundation
 import SwiftUI
 import XCTest
 
+@MainActor
 final class DecorativeColorsTests: XCTestCase {
     struct TestCase {
         let input: String

compound-ios/Tests/CompoundTests/FontSizeTests.swift

@@ -10,6 +10,7 @@
 import SwiftUI
 import XCTest
 
+@MainActor
 final class FontSizeTests: XCTestCase {
     /// Test all system text styles to assert mapping between `Font` and `UIFont`.
     func testTextStyle() {
@@ -103,3 +104,4 @@ final class FontSizeTests: XCTestCase {
         XCTAssertEqual(styledCustomFootnote15FontSize?.style, .footnote)
     }
 }
+ 

compound-ios/Tests/CompoundTests/OverrideColorTests.swift

@@ -10,20 +10,25 @@
 import Foundation
 import XCTest
 
-@MainActor
-class OverrideColorTests: XCTestCase {
-    func testSwiftUI() {
-        let colors = CompoundColors()
-        let tokens = CompoundColorTokens()
-        XCTAssertEqual(colors.textPrimary, tokens.textPrimary)
-        
-        colors.override(\.textPrimary, with: .pink)
-        XCTAssertEqual(colors.textPrimary, .pink)
-        
-        colors.override(\.textPrimary, with: nil)
-        XCTAssertEqual(colors.textPrimary, tokens.textPrimary)
+final class OverrideColorTests: XCTestCase {
+    func testSwiftUI() async {
+        // For some very weird reason we need this to be async, `@MainActor` is not enough
+        // it will compile but when running it will crash at the end of the run due to some deinit problems.
+        // The other solution would be to make CompoundColors nonisolated but we don't really need that.
+        await MainActor.run {
+            let colors = CompoundColors()
+            let tokens = CompoundColorTokens()
+            XCTAssertEqual(colors.textPrimary, tokens.textPrimary)
+            
+            colors.override(\.textPrimary, with: .pink)
+            XCTAssertEqual(colors.textPrimary, .pink)
+            
+            colors.override(\.textPrimary, with: nil)
+            XCTAssertEqual(colors.textPrimary, tokens.textPrimary)
+        }
     }
     
+    /// UIColors are nonisolated, so this is fine.
     func testUIKit() {
         let colors = CompoundUIColors()
         let tokens = CompoundUIColorTokens()

compound-ios/Tests/CompoundTests/PreviewTests.swift

@@ -8,7 +8,7 @@
 
 import Combine
 @testable import Compound
-@testable import SnapshotTesting
+@preconcurrency @testable import SnapshotTesting
 import SwiftUI
 import XCTest
 
@@ -28,15 +28,17 @@ class PreviewTests: XCTestCase {
                                                      .init(name: "iPad", device: "iPad")]
     private var recordMode: SnapshotTestingConfiguration.Record = .missing
 
-    override func setUp() {
-        super.setUp()
+    override func setUp() async throws {
+        try await super.setUp()
         
-        if ProcessInfo().environment["RECORD_FAILURES"].map(Bool.init) == true {
-            recordMode = .failed
-        }
+        await MainActor.run {
+            if ProcessInfo().environment["RECORD_FAILURES"].map(Bool.init) == true {
+                recordMode = .failed
+            }
 
-        checkEnvironments()
-        UIView.setAnimationsEnabled(false)
+            checkEnvironments()
+            UIView.setAnimationsEnabled(false)
+        }
     }
     
     /// Check environments to avoid problems with snapshots on different devices or OS.
@@ -183,6 +185,7 @@ private extension PreviewDevice {
 }
 
 private extension Snapshotting where Value: SwiftUI.View, Format == UIImage {
+    @MainActor
     static func prefireImage(drawHierarchyInKeyWindow: Bool = false,
                              preferences: SnapshotPreferences,
                              layout: SwiftUISnapshotLayout = .sizeThatFits,
@@ -204,7 +207,7 @@ private extension Snapshotting where Value: SwiftUI.View, Format == UIImage {
         }
 
         return SimplySnapshotting<UIImage>(pathExtension: "png", diffing: .prefireImage(preferences: preferences, scale: traits.displayScale))
-            .asyncPullback { view in
+            .asyncPullback { @MainActor view in
                 var config = config
 
                 let controller: UIViewController