Add sizeThatFits for UIHostingView

Package.swift

@@ -115,6 +115,19 @@ let swiftLogCondition = envEnable("OPENSWIFTUI_SWIFT_LOG", default: !buildForDar
 
 let swiftCryptoCondition = envEnable("OPENSWIFTUI_SWIFT_CRYPTO", default: !buildForDarwinPlatform)
 
+// MARK: - [env] OPENSWIFTUI_RENDER_GTK
+
+let renderGTKCondition = envEnable("OPENSWIFTUI_RENDER_GTK", default: !buildForDarwinPlatform)
+
+let cgtkTarget = Target.systemLibrary(
+    name: "CGTK",
+    pkgConfig: "gtk4",
+    providers: [
+        .brew(["gtk4"]),
+        .apt(["libgtk-4-dev clang"]),
+    ]
+)
+
 // MARK: - [env] OPENGSWIFTUI_SWIFTUI_RENDER
 
 let swiftUIRenderCondition = envEnable("OPENSWIFTUI_SWIFTUI_RENDER", default: buildForDarwinPlatform)
@@ -153,9 +166,10 @@ if libraryEvolutionCondition && !openCombineCondition && !swiftLogCondition {
 // MARK: - [env] OPENSWIFTUI_COMPATIBILITY_TEST
 
 let compatibilityTestCondition = envEnable("OPENSWIFTUI_COMPATIBILITY_TEST")
-
-if compatibilityTestCondition {
-    sharedSwiftSettings.append(.define("OPENSWIFTUI_COMPATIBILITY_TEST"))
+sharedCSettings.append(.define("OPENSWIFTUI", to: compatibilityTestCondition ? "0" : "1"))
+sharedCxxSettings.append(.define("OPENSWIFTUI", to: compatibilityTestCondition ? "0" : "1"))
+if !compatibilityTestCondition {
+    sharedSwiftSettings.append(.define("OPENSWIFTUI"))
 }
 
 // MARK: - [env] OPENSWIFTUI_IGNORE_AVAILABILITY
@@ -268,6 +282,8 @@ let openSwiftUITestsSupportTarget = Target.target(
     dependencies: [
         "OpenSwiftUI",
     ],
+    cSettings: sharedCSettings,
+    cxxSettings: sharedCxxSettings,
     swiftSettings: sharedSwiftSettings
 )
 
@@ -396,36 +412,48 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-numerics", from: "1.0.3"),
     ],
     targets: [
-        // TODO: Add SwiftGTK as an backend alternative for UIKit/AppKit on Linux and macOS
-        .systemLibrary(
-            name: "CGTK",
-            pkgConfig: "gtk4",
-            providers: [
-                .brew(["gtk4"]),
-                .apt(["libgtk-4-dev clang"]),
-            ]
-        ),
         coreGraphicsShimsTarget,
-        coreGraphicsShimsTestTarget,
-
         openSwiftUISPITarget,
-        openSwiftUISPITestTarget,
-
         openSwiftUICoreTarget,
-        openSwiftUICoreTestTarget,
-
         cOpenSwiftUITarget,
         openSwiftUITarget,
         openSwiftUITestsSupportTarget,
         openSwiftUIExtensionTarget,
-        openSwiftUITestTarget,
-        openSwiftUICompatibilityTestTarget,
-
         openSwiftUIBridgeTarget,
-        openSwiftUIBridgeTestTarget,
     ]
 )
 
+if renderGTKCondition {
+    package.targets.append(cgtkTarget)
+}
+
+if !compatibilityTestCondition {
+    package.targets.append(contentsOf: [
+        coreGraphicsShimsTestTarget,
+        openSwiftUISPITestTarget,
+        openSwiftUICoreTestTarget,
+        openSwiftUITestTarget,
+        openSwiftUIBridgeTestTarget,
+    ])
+}
+
+if buildForDarwinPlatform {
+    package.targets.append(openSwiftUICompatibilityTestTarget)
+}
+
+// MARK: - SymbolLocator
+
+if symbolLocatorCondition {
+    package.dependencies.append(
+        .package(url: "https://github.com/OpenSwiftUIProject/SymbolLocator.git", from: "0.2.0")
+    )
+
+    package.targets += [
+        openSwiftUISymbolDualTestsSupportTarget,
+        openSwiftUISymbolDualTestsTarget,
+    ]
+}
+
 extension Target {
     func addAGSettings() {
         // FIXME: Weird SwiftPM behavior for test Target. Otherwize we'll get the following error message
@@ -557,19 +585,6 @@ if swiftCryptoCondition {
     openSwiftUITarget.addSwiftCryptoSettings()
 }
 
-// MARK: - SymbolLocator
-
-if symbolLocatorCondition {
-    package.dependencies.append(
-        .package(url: "https://github.com/OpenSwiftUIProject/SymbolLocator.git", from: "0.2.0")
-    )
-
-    package.targets += [
-        openSwiftUISymbolDualTestsSupportTarget,
-        openSwiftUISymbolDualTestsTarget,
-    ]
-}
-
 extension [Platform] {
     static var darwinPlatforms: [Platform] {
         [.macOS, .iOS, .macCatalyst, .tvOS, .watchOS, .visionOS]

Sources/OpenSwiftUI/Integration/Hosting/AppKit/Controller/NSHostingController.swift

@@ -140,12 +140,9 @@ open class NSHostingController<Content>: NSViewController where Content: View {
         return result
     }
 
-
     public func _forEachIdentifiedView(body: (_IdentifiedViewProxy) -> Void) {
         host.forEachIdentifiedView(body: body)
     }
-
-
 }
 
 #endif

Sources/OpenSwiftUI/Integration/Hosting/UIKit/View/UIHostingView.swift

@@ -295,7 +295,11 @@ open class _UIHostingView<Content>: UIView, XcodeViewDebugDataProvider where Con
             UIEdgeInsets(top: explicitSafeAreaInsets.top, left: explicitSafeAreaInsets.leading, bottom: explicitSafeAreaInsets.bottom, right: explicitSafeAreaInsets.trailing)
         }
     }
-
+
+    override dynamic open func sizeThatFits(_ size: CGSize) -> CGSize {
+        base._layoutSizeThatFits(size)
+    }
+
     // FIXME
     final public func _viewDebugData() -> [_ViewDebug.Data] {
         // TODO

Sources/OpenSwiftUI/Integration/Hosting/UIKit/View/UIHostingViewBase.swift

@@ -168,6 +168,22 @@ package class UIHostingViewBase {
         }
     }
 
+    func _layoutSizeThatFits(
+        _ size: CGSize
+        // fixedAxes: _UILayoutAxes
+    ) -> CGSize {
+        guard let host else {
+            return .zero
+        }
+        let maxValue = 2777780.0
+        let fittingSize = host.sizeThatFits(.init(
+            width: size.width >= maxValue ? nil : size.width,
+            height: size.height >= maxValue ? nil : size.height
+        ))
+        let pixelLength = host.viewGraph.environment.pixelLength
+        return fittingSize.rounded(.up, toMultipleOf: pixelLength)
+    }
+
     //    func _baselineOffsets(at: CGSize) -> _UIBaselineOffsetPair
 
     // MARK: - Update

Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift

@@ -466,10 +466,42 @@ extension ViewGraph {
 
 //package typealias SizeThatFitsObservers = ViewGraphGeometryObservers<SizeThatFitsMeasurer>
 extension ViewGraph {
+    private var layoutComputer: LayoutComputer? {
+        guard requestedOutputs.contains(.layout) else {
+            preconditionFailure("Cannot fetch layout computer without layout output")
+        }
+        instantiateIfNeeded()
+        return rootLayoutComputer
+    }
+
+    private var rootViewInsets: EdgeInsets {
+        guard !safeAreaInsets.elements.isEmpty else {
+            return .zero
+        }
+        // FIXME
+        return .zero
+    }
+
+    static func sizeThatFits(
+        _ proposal: _ProposedSize,
+        layoutComputer: LayoutComputer?,
+        insets: EdgeInsets
+    ) -> CGSize {
+        var proposal = proposal
+        proposal.width = proposal.width.map { max($0 - insets.horizontal, .zero) }
+        proposal.height = proposal.width.map { max($0 - insets.vertical, .zero) }
+        let fittingSize = if let layoutComputer {
+            layoutComputer.sizeThatFits(proposal)
+        } else {
+            CGSize(width: 10.0, height: 10.0)
+        }
+        return fittingSize.outset(by: insets)
+    }
+
     package func sizeThatFits(_ proposal: _ProposedSize) -> CGSize {
-        _openSwiftUIUnimplementedFailure()
+        Self.sizeThatFits(proposal, layoutComputer: layoutComputer, insets: rootViewInsets)
     }
-    
+
     package func explicitAlignment(of guide: VerticalAlignment, at size: CGSize) -> CGFloat? {
         _openSwiftUIUnimplementedFailure()
     }

Sources/OpenSwiftUICore/View/Graph/ViewRendererHost.swift

@@ -373,8 +373,7 @@ extension ViewRendererHost {
     }
 
     package func sizeThatFits(_ proposal: _ProposedSize) -> CGSize {
-        updateViewGraph { $0.sizeThatFits(proposal)
-        }
+        updateViewGraph { $0.sizeThatFits(proposal) }
     }
     package func explicitAlignment(of guide: HorizontalAlignment, at size: CGSize) -> CGFloat? {
         updateViewGraph { $0.explicitAlignment(of: guide, at: size) }

Sources/OpenSwiftUITestsSupport/Integration/PlatformAlias.swift

@@ -2,10 +2,10 @@
 //  PlatformAlias.swift
 //  OpenSwiftUITestsSupport
 
-#if OPENSWIFTUI_COMPATIBILITY_TEST
-package import SwiftUI
-#else
+#if OPENSWIFTUI
 package import OpenSwiftUI
+#else
+package import SwiftUI
 #endif
 
 #if os(iOS)

Sources/OpenSwiftUITestsSupport/Integration/PlatformHostingControllerHelper.swift

@@ -32,7 +32,7 @@ extension PlatformHostingController {
 
 // FIXME: A workaround to bypass the Issue #87
 package func workaroundIssue87(_ vc: PlatformViewController) {
-    #if !OPENSWIFTUI_COMPATIBILITY_TEST
+    #if OPENSWIFTUI
     // TODO: Use swift-test exist test feature to detect the crash instead or sliently workaroun it
     CrashWorkaround.shared.objects.append(vc)
     #endif

Tests/OpenSwiftUICompatibilityTests/Animation/Animation/AnimationCompatibilityTests.swift

@@ -9,10 +9,10 @@ struct AnimationCompatibilityTests {
     func description() {
         let animation = Animation.default
         #expect(animation.description == "DefaultAnimation()")
-        #if OPENSWIFTUI_COMPATIBILITY_TEST
-        #expect(animation.debugDescription == "AnyAnimator(SwiftUI.DefaultAnimation())")
-        #else
+        #if OPENSWIFTUI
         #expect(animation.debugDescription == "AnyAnimator(OpenSwiftUICore.DefaultAnimation())")
+        #else
+        #expect(animation.debugDescription == "AnyAnimator(SwiftUI.DefaultAnimation())")
         #endif
         #expect(animation.customMirror.description == "Mirror for Animation")
     }

Tests/OpenSwiftUICompatibilityTests/Export.swift

@@ -2,10 +2,10 @@
 //  Export.swift
 //  OpenSwiftUICompatibilityTests
 
-#if OPENSWIFTUI_COMPATIBILITY_TEST
-@_exported import SwiftUI
-let compatibilityTestEnabled = true
-#else
+#if OPENSWIFTUI
 @_exported import OpenSwiftUI
 let compatibilityTestEnabled = false
+#else
+@_exported import SwiftUI
+let compatibilityTestEnabled = true
 #endif

Tests/OpenSwiftUICompatibilityTests/Graphics/Color/ColorResolvedTests.swift

@@ -3,7 +3,7 @@
 //  OpenSwiftUICompatibilityTests
 
 import Testing
-#if !OPENSWIFTUI_COMPATIBILITY_TEST
+#if OPENSWIFTUI
 @_spi(ForTestOnly)
 import OpenSwiftUI
 #endif
@@ -38,23 +38,23 @@ struct ColorResolvedTests {
         swiftUIExpected: String,
         openSwiftUIExpected: String
     ) {
-        #if OPENSWIFTUI_COMPATIBILITY_TEST
-        guard #available(iOS 17, macOS 14, *) else {
-            print("This test is not available")
-            return
-        }
-        let resolved = Color.Resolved(colorSpace: colorSpace, red: red, green: green, blue: blue, opacity: opacity)
-        #expect(resolved.description == swiftUIExpected)
-        #else
+        #if OPENSWIFTUI
         Update.locked {
             Color.Resolved._alignWithSwiftUIImplementation = false
             let resolved = Color.Resolved(colorSpace: colorSpace, red: red, green: green, blue: blue, opacity: opacity)
             #expect(resolved.description == openSwiftUIExpected)
-            
+
             Color.Resolved._alignWithSwiftUIImplementation = true
             let resolved2 = Color.Resolved(colorSpace: colorSpace, red: red, green: green, blue: blue, opacity: opacity)
             #expect(resolved2.description == swiftUIExpected)
         }
+        #else
+        guard #available(iOS 17, macOS 14, *) else {
+            print("This test is not available")
+            return
+        }
+        let resolved = Color.Resolved(colorSpace: colorSpace, red: red, green: green, blue: blue, opacity: opacity)
+        #expect(resolved.description == swiftUIExpected)
         #endif
     }
 }

Tests/OpenSwiftUICompatibilityTests/README.md

@@ -3,9 +3,9 @@
 Test public API of OpenSwiftUI and run it against with SwiftUI on Apple Platform.
 
 ```swift
-#if OPENSWIFTUI_COMPATIBILITY_TEST
-import SwiftUI
-#else
+#if OPENSWIFTUI
 import OpenSwiftUI
+#else
+import SwiftUI
 #endif
 ```

Tests/OpenSwiftUICompatibilityTests/View/Debug/ChangedBodyPropertyTests.swift

@@ -16,19 +16,17 @@ struct ChangedBodyPropertyTests {
         let entries = try store
             .getEntries(at: position) // getEntries's with and at param is not respected on iOS, so I have to use last then.
             .compactMap { $0 as? OSLogEntryLog }
-            #if OPENSWIFTUI_COMPATIBILITY_TEST
-            .filter { $0.subsystem == "com.apple.SwiftUI" && $0.category == "Changed Body Properties" }
-            #else
+            #if OPENSWIFTUI
             .filter { $0.subsystem == "org.OpenSwiftUIProject.OpenSwiftUI" && $0.category == "Changed Body Properties" }
+            #else
+            .filter { $0.subsystem == "com.apple.SwiftUI" && $0.category == "Changed Body Properties" }
             #endif
             .map { $0.composedMessage }
         #expect(entries.last == expected)
     }
 
-    #if OPENSWIFTUI_COMPATIBILITY_TEST
+    #if !OPENSWIFTUI
     @available(iOS 17.1, macOS 14.1, *)
-    #else
-    @available(iOS 15, macOS 12, *)
     #endif
     @Test
     func zeroPropertyView() throws {
@@ -44,10 +42,8 @@ struct ChangedBodyPropertyTests {
         try verifyLog(expected: "ChangedBodyPropertyTests.ContentView: @self changed.")
     }
 
-    #if OPENSWIFTUI_COMPATIBILITY_TEST
+    #if !OPENSWIFTUI
     @available(iOS 17.1, macOS 14.1, *)
-    #else
-    @available(iOS 15, macOS 12, *)
     #endif
     @Test
     func propertyView() throws {
@@ -64,10 +60,8 @@ struct ChangedBodyPropertyTests {
         try verifyLog(expected: "ChangedBodyPropertyTests.ContentView: @self changed.")
     }
 
-    #if OPENSWIFTUI_COMPATIBILITY_TEST
+    #if !OPENSWIFTUI
     @available(iOS 17.1, macOS 14.1, *)
-    #else
-    @available(iOS 15, macOS 12, *)
     #endif
     @Test
     func statePropertyView() throws {

Tests/OpenSwiftUICompatibilityTests/View/EquatableViewTests.swift

@@ -137,7 +137,7 @@ struct EquatableViewTests {
         }
     }
 
-    #if !OPENSWIFTUI_COMPATIBILITY_TEST
+    #if OPENSWIFTUI
     struct Number: Equatable {
         var value: Int