Resolve many concurrency warnings

Examples/Demo/Demo/DemoView.swift

@@ -1,7 +1,7 @@
 import MarkdownUI
 import SwiftUI
 
-struct ThemeOption: Hashable {
+struct ThemeOption: Hashable, Sendable {
   let name: String
   let theme: Theme
 

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.6
+// swift-tools-version: 5.10
 
 import PackageDescription
 
@@ -28,6 +28,9 @@ let package = Package(
       dependencies: [
         "cmark-gfm",
         .product(name: "NetworkImage", package: "NetworkImage"),
+      ],
+      swiftSettings: [
+        .enableExperimentalFeature("StrictConcurrency"),
       ]
     ),
     .testTarget(

Sources/MarkdownUI/DSL/Blocks/ListItem.swift

@@ -23,7 +23,7 @@ import Foundation
 /// ```
 ///
 /// ![](ListItem)
-public struct ListItem: Hashable {
+public struct ListItem: Hashable, Sendable {
   let children: [BlockNode]
 
   init(children: [BlockNode]) {

Sources/MarkdownUI/DSL/Blocks/MarkdownContent.swift

@@ -59,7 +59,7 @@ public protocol MarkdownContentProtocol {
 ///   }
 /// }
 /// ```
-public struct MarkdownContent: Equatable, MarkdownContentProtocol {
+public struct MarkdownContent: Equatable, MarkdownContentProtocol, Sendable {
   /// Returns a Markdown content value with the sum of the contents of all the container blocks
   /// present in this content.
   ///

Sources/MarkdownUI/DSL/Blocks/TaskListItem.swift

@@ -22,7 +22,7 @@ import Foundation
 ///   }
 /// }
 /// ```
-public struct TaskListItem: Hashable {
+public struct TaskListItem: Hashable, Sendable {
   let isCompleted: Bool
   let children: [BlockNode]
 

Sources/MarkdownUI/DSL/Inlines/SoftBreak.swift

@@ -3,7 +3,7 @@ import Foundation
 /// A soft break in a Markdown content block.
 ///
 /// A ``Markdown`` view will display a soft break as a space.
-public struct SoftBreak: InlineContentProtocol {
+public struct SoftBreak: InlineContentProtocol, Sendable {
   /// Creates a soft break inline element.
   public init() {}
 
@@ -13,7 +13,7 @@ public struct SoftBreak: InlineContentProtocol {
 }
 
 extension SoftBreak {
-  public enum Mode {
+  public enum Mode: Sendable {
     /// Treat a soft break as a space
     case space
 

Sources/MarkdownUI/Extensibility/AssetImageProvider.swift

@@ -12,24 +12,24 @@ import SwiftUI
 /// }
 /// .markdownImageProvider(.asset)
 /// ```
-public struct AssetImageProvider: ImageProvider {
-  private let name: (URL) -> String
+public struct AssetImageProvider: ImageProvider, Sendable {
+  private let name: @Sendable (URL) -> String
   private let bundle: Bundle?
 
   /// Creates an asset image provider.
   /// - Parameters:
   ///   - name: A closure that extracts the image resource name from the URL in the Markdown content.
   ///   - bundle: The bundle where the image resources are located. Specify `nil` to search the app’s main bundle.
   public init(
-    name: @escaping (URL) -> String = \.lastPathComponent,
+    name: @Sendable @escaping (URL) -> String = \.lastPathComponent,
     bundle: Bundle? = nil
   ) {
     self.name = name
     self.bundle = bundle
   }
 
   public func makeImage(url: URL?) -> some View {
-    if let url = url, let image = self.image(url: url) {
+    if let url, let image = self.image(url: url) {
       ResizeToFit(idealSize: image.size) {
         Image(platformImage: image)
           .resizable()

Sources/MarkdownUI/Extensibility/AssetInlineImageProvider.swift

@@ -2,15 +2,15 @@ import SwiftUI
 
 /// An inline image provider that loads images from resources located in an app or a module.
 public struct AssetInlineImageProvider: InlineImageProvider {
-  private let name: (URL) -> String
+  private let name: @Sendable (URL) -> String
   private let bundle: Bundle?
 
   /// Creates an asset inline image provider.
   /// - Parameters:
   ///   - name: A closure that extracts the image resource name from the URL in the Markdown content.
   ///   - bundle: The bundle where the image resources are located. Specify `nil` to search the app’s main bundle.
   public init(
-    name: @escaping (URL) -> String = \.lastPathComponent,
+    name: @Sendable @escaping (URL) -> String = \.lastPathComponent,
     bundle: Bundle? = nil
   ) {
     self.name = name

Sources/MarkdownUI/Extensibility/CodeSyntaxHighlighter.swift

@@ -4,7 +4,7 @@ import SwiftUI
 ///
 /// To configure the current code syntax highlighter for a view hierarchy, use the
 /// `markdownCodeSyntaxHighlighter(_:)` modifier.
-public protocol CodeSyntaxHighlighter {
+public protocol CodeSyntaxHighlighter: Sendable {
   /// Returns a text view configured with the syntax highlighted code.
   /// - Parameters:
   ///   - code: The code block.

Sources/MarkdownUI/Extensibility/ImageProvider.swift

@@ -13,7 +13,7 @@ import SwiftUI
 /// }
 /// .markdownImageProvider(.asset)
 /// ```
-public protocol ImageProvider {
+public protocol ImageProvider: Sendable {
   /// A view that loads and displays an image.
   associatedtype Body: View
 
@@ -26,8 +26,8 @@ public protocol ImageProvider {
   @ViewBuilder func makeImage(url: URL?) -> Body
 }
 
-struct AnyImageProvider: ImageProvider {
-  private let _makeImage: (URL?) -> AnyView
+struct AnyImageProvider: ImageProvider, Sendable {
+  private let _makeImage: @Sendable (URL?) -> AnyView
 
   init<I: ImageProvider>(_ imageProvider: I) {
     self._makeImage = {

Sources/MarkdownUI/Extensibility/InlineImageProvider.swift

@@ -4,7 +4,7 @@ import SwiftUI
 ///
 /// To configure the current inline image provider for a view hierarchy,
 /// use the `markdownInlineImageProvider(_:)` modifier.
-public protocol InlineImageProvider {
+public protocol InlineImageProvider: Sendable {
   /// Returns an image for the given URL.
   ///
   /// ``Markdown`` views call this method to load images within a line of text.

Sources/MarkdownUI/Parser/BlockNode.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-enum BlockNode: Hashable {
+enum BlockNode: Hashable, Sendable {
   case blockquote(children: [BlockNode])
   case bulletedList(isTight: Bool, items: [RawListItem])
   case numberedList(isTight: Bool, start: Int, items: [RawListItem])
@@ -35,26 +35,26 @@ extension BlockNode {
   }
 }
 
-struct RawListItem: Hashable {
+struct RawListItem: Hashable, Sendable {
   let children: [BlockNode]
 }
 
-struct RawTaskListItem: Hashable {
+struct RawTaskListItem: Hashable, Sendable {
   let isCompleted: Bool
   let children: [BlockNode]
 }
 
-enum RawTableColumnAlignment: Character {
+enum RawTableColumnAlignment: Character, Sendable {
   case none = "\0"
   case left = "l"
   case center = "c"
   case right = "r"
 }
 
-struct RawTableRow: Hashable {
+struct RawTableRow: Hashable, Sendable {
   let cells: [RawTableCell]
 }
 
-struct RawTableCell: Hashable {
+struct RawTableCell: Hashable, Sendable {
   let content: [InlineNode]
 }

Sources/MarkdownUI/Theme/BlockStyle/BlockConfiguration.swift

@@ -5,6 +5,7 @@ import SwiftUI
 /// Most theme ``BlockStyle`` instances receive a `BlockConfiguration` input in their
 /// `body` closure. The configuration ``BlockConfiguration/label-swift.property``
 /// property reflects the block's content.
+@MainActor
 public struct BlockConfiguration {
   /// A type-erased view of a Markdown block.
   public struct Label: View {

Sources/MarkdownUI/Theme/BlockStyle/BlockStyle.swift

@@ -37,12 +37,13 @@ import SwiftUI
 /// ```
 ///
 /// ![](CustomBlockquote)
+@MainActor
 public struct BlockStyle<Configuration> {
-  private let body: (Configuration) -> AnyView
+  private let body: @MainActor (Configuration) -> AnyView
 
   /// Creates a block style that customizes a block by applying the given body.
   /// - Parameter body: A view builder that returns the customized block.
-  public init<Body: View>(@ViewBuilder body: @escaping (_ configuration: Configuration) -> Body) {
+  public init<Body: View>(@ViewBuilder body: @MainActor @escaping (_ configuration: Configuration) -> Body) {
     self.body = { AnyView(body($0)) }
   }
 
@@ -54,7 +55,7 @@ public struct BlockStyle<Configuration> {
 extension BlockStyle where Configuration == Void {
   /// Creates a block style for a block with no content, like a thematic break.
   /// - Parameter body: A view builder that returns the customized block.
-  public init<Body: View>(@ViewBuilder body: @escaping () -> Body) {
+  public init<Body: View>(@ViewBuilder body: @MainActor @escaping () -> Body) {
     self.init { _ in
       body()
     }

Sources/MarkdownUI/Theme/BlockStyle/ListMarkerConfiguration.swift

@@ -4,7 +4,7 @@ import SwiftUI
 ///
 /// The theme ``Theme/bulletedListMarker`` and ``Theme/numberedListMarker``
 /// block styles receive a `ListMarkerConfiguration` input in their `body` closure.
-public struct ListMarkerConfiguration {
+public struct ListMarkerConfiguration: Sendable {
   /// The list level (one-based) of the item to which the marker applies.
   public let listLevel: Int
 

Sources/MarkdownUI/Theme/BlockStyle/TableBackgroundStyle.swift

@@ -27,13 +27,13 @@ import SwiftUI
 /// ```
 ///
 /// ![](CustomTableBackground)
-public struct TableBackgroundStyle {
-  let background: (_ row: Int, _ column: Int) -> AnyShapeStyle
+public struct TableBackgroundStyle: Sendable {
+  let background: @Sendable (_ row: Int, _ column: Int) -> AnyShapeStyle
 
   /// Creates a table background style that customizes table backgrounds by applying a given closure
   /// to the background of each cell.
   /// - Parameter background: A closure that returns a shape style for a given table cell location.
-  public init<S: ShapeStyle>(background: @escaping (_ row: Int, _ column: Int) -> S) {
+  public init<S: ShapeStyle>(background: @Sendable @escaping (_ row: Int, _ column: Int) -> S) {
     self.background = { row, column in
       AnyShapeStyle(background(row, column))
     }

Sources/MarkdownUI/Theme/BlockStyle/TableBorderStyle.swift

@@ -30,7 +30,7 @@ import SwiftUI
 /// ```
 ///
 /// ![](CustomTableBorders)
-public struct TableBorderStyle {
+public struct TableBorderStyle: Sendable {
   /// The visible table borders.
   public var visibleBorders: TableBorderSelector
 

Sources/MarkdownUI/Theme/TextStyle/Styles/FontProperties.swift

@@ -1,9 +1,9 @@
 import SwiftUI
 
 /// The characteristics of a font.
-public struct FontProperties: Hashable {
+public struct FontProperties: Hashable, Sendable {
   /// The font family.
-  public enum Family: Hashable {
+  public enum Family: Hashable, Sendable {
     /// The system font family.
     case system(Font.Design = .default)
 
@@ -12,7 +12,7 @@ public struct FontProperties: Hashable {
   }
 
   /// The font family variant.
-  public enum FamilyVariant: Hashable {
+  public enum FamilyVariant: Hashable, Sendable {
     /// No variant. Use the current font family.
     case normal
 
@@ -21,7 +21,7 @@ public struct FontProperties: Hashable {
   }
 
   /// The font caps variant.
-  public enum CapsVariant: Hashable {
+  public enum CapsVariant: Hashable, Sendable {
     /// Don't use a font caps variant.
     case normal
 
@@ -36,7 +36,7 @@ public struct FontProperties: Hashable {
   }
 
   /// The font digit variant.
-  public enum DigitVariant: Hashable {
+  public enum DigitVariant: Hashable, Sendable {
     /// Don't use a font digit variant.
     case normal
 
@@ -45,7 +45,7 @@ public struct FontProperties: Hashable {
   }
 
   /// The font style.
-  public enum Style {
+  public enum Style: Sendable {
     /// Don't use a font style.
     case normal
 
@@ -102,7 +102,7 @@ public struct FontProperties: Hashable {
     set { self.widthStorage = newValue }
   }
 
-  private var widthStorage: AnyHashable?
+  nonisolated(unsafe) private var widthStorage: AnyHashable? // Marking this as `nonisolated(unsafe)`, because it should really be `Font.Width?`, but this is only available from iOS 16. Change to type `Font.Width?` and remove `nonisolated(unsafe)` after raising minimum target to iOS 16
 
   /// The font size.
   public var size: CGFloat = Self.defaultSize

Sources/MarkdownUI/Theme/TextStyle/Styles/FontPropertiesAttribute.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-enum FontPropertiesAttribute: AttributedStringKey {
+enum FontPropertiesAttribute: AttributedStringKey, Sendable {
   typealias Value = FontProperties
   static let name = "fontProperties"
 }

Sources/MarkdownUI/Theme/TextStyle/Styles/FontSize.swift

@@ -1,8 +1,8 @@
 import Foundation
 
 /// A text style that sets the font size.
-public struct FontSize: TextStyle {
-  private enum Size {
+public struct FontSize: TextStyle, Sendable {
+  private enum Size: Sendable {
     case points(CGFloat)
     case relative(RelativeSize)
   }

Sources/MarkdownUI/Theme/TextStyle/TextStyle.swift

@@ -57,6 +57,6 @@ import SwiftUI
 /// ```
 ///
 /// ![](CustomBlockquote)
-public protocol TextStyle {
+public protocol TextStyle: Sendable {
   func _collectAttributes(in attributes: inout AttributeContainer)
 }

Sources/MarkdownUI/Theme/Theme.swift

@@ -99,7 +99,8 @@ import SwiftUI
 ///   }
 ///   // More block styles...
 /// ```
-public struct Theme {
+@MainActor
+public struct Theme: Sendable {
   /// The default text style.
   public var text: TextStyle = EmptyTextStyle()
 

Sources/MarkdownUI/Utility/Deprecations.swift

@@ -369,8 +369,8 @@ extension View {
     "BlockStyle" types.
     """
 )
-public struct MarkdownStyle: Hashable {
-  public struct Font: Hashable {
+public struct MarkdownStyle: Hashable, Sendable {
+  public struct Font: Hashable, Sendable {
     public static var largeTitle: Self { fatalError("Unimplemented") }
     public static var title: Self { fatalError("Unimplemented") }
     public static var title2: Self { fatalError("Unimplemented") }
@@ -423,7 +423,7 @@ public struct MarkdownStyle: Hashable {
     }
   }
 
-  public struct HeadingScales: Hashable {
+  public struct HeadingScales: Hashable, Sendable {
     public init(
       h1: CGFloat,
       h2: CGFloat,
@@ -444,7 +444,7 @@ public struct MarkdownStyle: Hashable {
     }
   }
 
-  public struct Measurements: Hashable {
+  public struct Measurements: Hashable, Sendable {
     public var codeFontScale: CGFloat
     public var headIndentStep: CGFloat
     public var tailIndentStep: CGFloat

Sources/MarkdownUI/Utility/InlineNode+RawImageData.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-struct RawImageData: Hashable {
+struct RawImageData: Hashable, Sendable {
   var source: String
   var alt: String
   var destination: String?