Backporting to iOS 17, macOS 14.

Package.swift

@@ -5,11 +5,11 @@ import PackageDescription
 let package = Package(
   name: "textual",
   platforms: [
-    .macOS(.v15),
-    .iOS(.v18),
-    .tvOS(.v18),
-    .watchOS(.v11),
-    .visionOS(.v2),
+    .macOS(.v14),
+    .iOS(.v17),
+    .tvOS(.v17),
+    .watchOS(.v10),
+    .visionOS(.v1),
   ],
   products: [
     .library(name: "Textual", targets: ["Textual"])

Sources/Textual/Attachment/AttachmentLoader.swift

@@ -56,7 +56,22 @@ public protocol AttachmentLoader: Sendable {
   ) async throws -> Attachment
 }
 
+private struct ImageAttachmentLoaderKey: EnvironmentKey {
+  nonisolated(unsafe) static let defaultValue: any AttachmentLoader = .image()
+}
+
+private struct EmojiAttachmentLoaderKey: EnvironmentKey {
+  nonisolated(unsafe) static let defaultValue: any AttachmentLoader = .emoji()
+}
+
 extension EnvironmentValues {
-  @Entry var imageAttachmentLoader: any AttachmentLoader = .image()
-  @Entry var emojiAttachmentLoader: any AttachmentLoader = .emoji()
+  var imageAttachmentLoader: any AttachmentLoader {
+    get { self[ImageAttachmentLoaderKey.self] }
+    set { self[ImageAttachmentLoaderKey.self] = newValue }
+  }
+
+  var emojiAttachmentLoader: any AttachmentLoader {
+    get { self[EmojiAttachmentLoaderKey.self] }
+    set { self[EmojiAttachmentLoaderKey.self] = newValue }
+  }
 }

Sources/Textual/EmojiProperties.swift

@@ -25,6 +25,13 @@ public struct EmojiProperties: Sendable, Hashable {
   }
 }
 
+private struct EmojiPropertiesKey: EnvironmentKey {
+  static let defaultValue = EmojiProperties()
+}
+
 extension EnvironmentValues {
-  @Entry var emojiProperties = EmojiProperties()
+  var emojiProperties: EmojiProperties {
+    get { self[EmojiPropertiesKey.self] }
+    set { self[EmojiPropertiesKey.self] = newValue }
+  }
 }

Sources/Textual/InlineText/InlineStyle.swift

@@ -77,7 +77,14 @@ public struct InlineStyle: Sendable, Hashable {
   }
 }
 
+private struct InlineStyleKey: EnvironmentKey {
+  nonisolated(unsafe) static let defaultValue: InlineStyle = .default
+}
+
 extension EnvironmentValues {
   @usableFromInline
-  @Entry var inlineStyle: InlineStyle = .default
+  var inlineStyle: InlineStyle {
+    get { self[InlineStyleKey.self] }
+    set { self[InlineStyleKey.self] = newValue }
+  }
 }

Sources/Textual/Internal/Attachment/AttachmentAttribute.swift

@@ -13,6 +13,7 @@ import SwiftUI
 // `Text.Layout.Run` exposes lightweight accessors so overlay code can discover attachments without
 // reaching back into the original attributed string.
 
+@available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *)
 struct AttachmentAttribute: TextAttribute {
   var attachment: AnyAttachment
   var presentationIntent: PresentationIntent?
@@ -23,6 +24,7 @@ struct AttachmentAttribute: TextAttribute {
   }
 }
 
+@available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *)
 extension Text.Layout.Run {
   var attachment: AnyAttachment? {
     self[AttachmentAttribute.self]?.attachment

Sources/Textual/Internal/Attachment/AttachmentOverlay.swift

@@ -17,17 +17,21 @@ struct AttachmentOverlay: ViewModifier {
   }
 
   func body(content: Content) -> some View {
-    content
-      .overlayPreferenceValue(Text.LayoutKey.self) { value in
-        if let anchoredLayout = value.first {
-          GeometryReader { geometry in
-            AttachmentView(
-              attachments: attachments,
-              origin: geometry[anchoredLayout.origin],
-              layout: anchoredLayout.layout
-            )
+    if #available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *) {
+      content
+        .overlayPreferenceValue(Text.LayoutKey.self) { value in
+          if let anchoredLayout = value.first {
+            GeometryReader { geometry in
+              AttachmentView(
+                attachments: attachments,
+                origin: geometry[anchoredLayout.origin],
+                layout: anchoredLayout.layout
+              )
+            }
           }
         }
-      }
+    } else {
+      content
+    }
   }
 }

Sources/Textual/Internal/Attachment/AttachmentView.swift

@@ -12,6 +12,7 @@ import SwiftUI
 // On macOS, when text selection is enabled, object-style attachments are dimmed when they fall
 // inside the selected range. Inline-style attachments (for example, emoji) are not dimmed.
 
+@available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *)
 struct AttachmentView: View {
   #if TEXTUAL_ENABLE_TEXT_SELECTION && canImport(AppKit)
     @Environment(TextSelectionModel.self) private var textSelectionModel: TextSelectionModel?

Sources/Textual/Internal/Backporting/CGSize+Hashable.swift

@@ -0,0 +1,13 @@
+import SwiftUI
+
+@available(iOS, introduced: 13.0, obsoleted: 18.0, message: "CGSize is Hashable by default in iOS 18")
+@available(macOS, introduced: 10.15, obsoleted: 15.0, message: "CGSize is Hashable by default in macOS 15")
+@available(watchOS, introduced: 6.0, obsoleted: 11.0, message: "CGSize is Hashable by default in watchOS 11")
+@available(tvOS, introduced: 13.0, obsoleted: 18.0, message: "CGSize is Hashable by default in tvOS 18")
+@available(visionOS, introduced: 1.0, obsoleted: 2.0, message: "CGSize is Hashable by default in visionOS 2")
+extension CGSize: @retroactive Hashable {
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(width)
+    hasher.combine(height)
+  }
+}

Sources/Textual/Internal/Backporting/SubviewGroup.swift

@@ -0,0 +1,33 @@
+import SwiftUI
+
+public struct SubviewGroup<Result: View>: View {
+  private let content: AnyView
+  private let transform: (_VariadicView.Children) -> Result
+
+  public init<Content: View>(
+    subviews content: Content,
+    @ViewBuilder transform: @escaping (_VariadicView.Children) -> Result
+  ) {
+    self.content = AnyView(content)
+    self.transform = transform
+  }
+
+  public var body: some View {
+    _VariadicView.Tree(
+      VariadicRoot(transform: transform)
+    ) {
+      content
+    }
+  }
+}
+
+private struct VariadicRoot<Result: View>: _VariadicView
+    .MultiViewRoot
+{
+  let transform: (_VariadicView.Children) -> Result
+
+  @ViewBuilder
+  func body(children: _VariadicView.Children) -> some View {
+    transform(children)
+  }
+}

Sources/Textual/Internal/StructuredText/BlockVStack.swift

@@ -20,7 +20,7 @@ extension StructuredText {
     }
 
     var body: some View {
-      Group(subviews: content) { children in
+      SubviewGroup(subviews: content) { children in
         BlockVStackLayout(textAlignment: textAlignment) {
           ForEach(children) {
             BlockLayoutView($0)
@@ -53,7 +53,8 @@ extension StructuredText {
       content
         .onPreferenceChange(BlockSpacingKey.self) { @MainActor value in
           // Override with the resolved list item spacing if enabled
-          blockSpacing = listItemSpacingEnabled ? resolvedListItemSpacing : value
+          blockSpacing =
+            listItemSpacingEnabled ? resolvedListItemSpacing : value
         }
         .layoutValue(key: BlockSpacingKey.self, value: blockSpacing)
     }
@@ -83,7 +84,8 @@ extension StructuredText {
 
     func sizeThatFits(
       proposal: ProposedViewSize,
-      subviews: Subviews, cache: inout Cache
+      subviews: Subviews,
+      cache: inout Cache
     ) -> CGSize {
       if let width = proposal.width, width <= 0 {
         return .zero
@@ -92,7 +94,9 @@ extension StructuredText {
       var size = CGSize.zero
 
       for view in subviews {
-        let viewSize = view.sizeThatFits(.init(width: proposal.width, height: nil))
+        let viewSize = view.sizeThatFits(
+          .init(width: proposal.width, height: nil)
+        )
         size.height += viewSize.height
         size.width = max(size.width, viewSize.width)
       }
@@ -105,7 +109,8 @@ extension StructuredText {
     func placeSubviews(
       in bounds: CGRect,
       proposal: ProposedViewSize,
-      subviews: Subviews, cache: inout Cache
+      subviews: Subviews,
+      cache: inout Cache
     ) {
       var currentY: CGFloat = 0
 

Sources/Textual/Internal/StructuredText/ListEnvironment.swift

@@ -1,7 +1,30 @@
 import SwiftUI
 
+private struct ListItemSpacingKey: EnvironmentKey {
+  static let defaultValue: FontScaled<StructuredText.BlockSpacing> = .fontScaled(top: 0.25)
+}
+
+private struct ResolvedListItemSpacingKey: EnvironmentKey {
+  static let defaultValue: StructuredText.BlockSpacing = .init()
+}
+
+private struct ListItemSpacingEnabledKey: EnvironmentKey {
+  static let defaultValue: Bool = false
+}
+
 extension EnvironmentValues {
-  @Entry var listItemSpacing: FontScaled<StructuredText.BlockSpacing> = .fontScaled(top: 0.25)
-  @Entry var resolvedListItemSpacing: StructuredText.BlockSpacing = .init()
-  @Entry var listItemSpacingEnabled: Bool = false
+  var listItemSpacing: FontScaled<StructuredText.BlockSpacing> {
+    get { self[ListItemSpacingKey.self] }
+    set { self[ListItemSpacingKey.self] = newValue }
+  }
+
+  var resolvedListItemSpacing: StructuredText.BlockSpacing {
+    get { self[ResolvedListItemSpacingKey.self] }
+    set { self[ResolvedListItemSpacingKey.self] = newValue }
+  }
+
+  var listItemSpacingEnabled: Bool {
+    get { self[ListItemSpacingEnabledKey.self] }
+    set { self[ListItemSpacingEnabledKey.self] = newValue }
+  }
 }

Sources/Textual/Internal/TextFragment/TextBuilder.swift

@@ -78,19 +78,23 @@ extension Text {
         // Create placeholder
         text = Text(placeholderSize: size)
           .baselineOffset(key.attachment.baselineOffset(in: runEnvironment))
-          .customAttribute(
+        if #available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *) {
+          text = text.customAttribute(
             AttachmentAttribute(
               key.attachment,
               presentationIntent: run.presentationIntent
             )
           )
+        }
       } else {
         text = Text(AttributedString(attributedString[run.range]))
       }
 
       // Add link attribute for TextLinkInteraction
       if let link = run.link {
-        text = text.customAttribute(LinkAttribute(link))
+        if #available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *) {
+          text = text.customAttribute(LinkAttribute(link))
+        }
       }
 
       return text

Sources/Textual/Internal/TextFragment/TextFragment.swift

@@ -36,8 +36,7 @@ struct TextFragment<Content: AttributedStringProtocol>: View {
   }
 
   var body: some View {
-    text
-      .customAttribute(TextFragmentAttribute())
+    taggedText
       .onGeometryChange(for: CGSize?.self, of: \.textContainerSize) { size in
         guard let size, let textBuilder else { return }
         textBuilder.sizeChanged(size, environment: textEnvironment)
@@ -50,14 +49,23 @@ struct TextFragment<Content: AttributedStringProtocol>: View {
       .modifier(TextLinkInteraction())
   }
 
+  @ViewBuilder private var taggedText: some View {
+    if #available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *) {
+      text.customAttribute(TextFragmentAttribute())
+    } else {
+      text
+    }
+  }
+
   private var text: Text {
     textBuilder?.text ?? Text(verbatim: "")
   }
 }
 
-struct TextFragmentAttribute: TextAttribute {
-}
+@available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *)
+struct TextFragmentAttribute: TextAttribute {}
 
+@available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *)
 extension Text.Layout {
   var isTextFragment: Bool {
     first?.first?[TextFragmentAttribute.self] != nil

Sources/Textual/Internal/TextInteraction/AppKit/AppKitTextInteractionOverlay.swift

@@ -10,6 +10,7 @@
   // manages selection gestures, keyboard-driven updates, and context menus while SwiftUI renders
   // the text.
 
+  @available(macOS 15, *)
   struct AppKitTextInteractionOverlay: NSViewRepresentable {
     private let model: TextSelectionModel
     private let overflowFrames: [CGRect]

Sources/Textual/Internal/TextInteraction/AppKit/AppKitTextSelectionInteraction.swift

@@ -10,8 +10,10 @@
   // `NSView` that handles selection gestures and context menus. The modifier also manages cursor updates,
   // switching between I-beam and pointing hand based on hover position over text or links.
 
+  @available(macOS 15, *)
   typealias PlatformTextSelectionInteraction = AppKitTextSelectionInteraction
 
+  @available(macOS 15, *)
   struct AppKitTextSelectionInteraction: ViewModifier {
     @State private var cursorPushed = false
 
@@ -34,7 +36,8 @@
         }
     }
 
-    private func updateCursor(for phase: HoverPhase, model: TextSelectionModel) {
+    private func updateCursor(for phase: HoverPhase, model: TextSelectionModel)
+    {
       switch phase {
       case .active(let location):
         let cursor =

Sources/Textual/Internal/TextInteraction/AppKit/AppKitTextSelectionView.swift

@@ -9,6 +9,7 @@
   // `TextSelectionModel` from the environment, computes selection rectangles for the current
   // range within this layout, and paints them in a `Canvas` behind the text.
 
+  @available(macOS 15, *)
   struct AppKitTextSelectionView: View {
     @Environment(TextSelectionModel.self) private var textSelectionModel: TextSelectionModel?
     @State private var selectionRects: [TextSelectionRect] = []

Sources/Textual/Internal/TextInteraction/AppKit/NSTextInteractionView.swift

@@ -10,6 +10,7 @@
   // so embedded scrollable regions continue to receive input events. Link taps are forwarded to
   // `openURL`.
 
+  @available(macOS 15, *)
   final class NSTextInteractionView: NSView {
     var model: TextSelectionModel
     var exclusionRects: [CGRect]
@@ -290,6 +291,7 @@
     }
   }
 
+  @available(macOS 15, *)
   extension NSTextInteractionView: NSUserInterfaceValidations {
     func validateUserInterfaceItem(_ item: any NSValidatedUserInterfaceItem) -> Bool {
       switch item.action {

Sources/Textual/Internal/TextInteraction/Shared/LinkAttribute.swift

@@ -1,5 +1,6 @@
 import SwiftUI
 
+@available(iOS 17.0, macOS 14.0, tvOS 17.0, watchOS 10.0, *)
 struct LinkAttribute: TextAttribute {
   var url: URL
 
@@ -8,6 +9,7 @@ struct LinkAttribute: TextAttribute {
   }
 }
 
+@available(iOS 17.0, macOS 14.0, tvOS 17.0, watchOS 10.0, *)
 extension Text.Layout.Run {
   var url: URL? {
     self[LinkAttribute.self]?.url

Sources/Textual/Internal/TextInteraction/Shared/TextLayout/EmptyTextLayoutCollection.swift

@@ -1,6 +1,7 @@
 #if TEXTUAL_ENABLE_TEXT_SELECTION
   import SwiftUI
 
+  @available(iOS 18, macOS 15, tvOS 18, watchOS 11, visionOS 2, *)
   struct EmptyTextLayoutCollection: TextLayoutCollection {
     var layouts: [any TextLayout] {
       []