fix: Use generic cells to avoid AnyView type erasure

Example/Example/Model/Creator.swift

@@ -74,9 +74,8 @@ class Creator: CollectionViewStreamingCollection {
                     return
                 }
                 let index = Int.random(in: 0..<items.count)
-                var item = items[index]
+                let item = items[index]
                 item.count += 1
-                items[index] = item  // We currently need to replace this because it's a struct.
                 collectionView?.updateItem(item, atIndex: index, items: items)
             }
 

Example/Example/Views/ContentView.swift

@@ -54,6 +54,7 @@ struct ContentView: View {
                         primaryAction(selection)
                     }
                 } else {
+                    // TODO: Think hard about memory leaks here.
                     SelectableCollectionView(model.filteredItems, selection: $model.selection, layout: layout) { item in
                         Cell(item: item, isPainted: model.isPainted)
                     } contextMenu: { selection in

Package.swift

@@ -15,7 +15,6 @@ let package = Package(
             targets: ["SelectableCollectionView"]),
     ],
     dependencies: [
-        .package(path: "MacResources"),
         .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
         .package(url: "https://github.com/inseven/licensable.git", .upToNextMajor(from: "0.0.1")),
         .package(url: "https://github.com/tribalworldwidelondon/CassowarySwift.git", from: "2.0.0"),
@@ -26,9 +25,6 @@ let package = Package(
             dependencies: [
                 .product(name: "Cassowary", package: "CassowarySwift"),
                 .product(name: "Licensable", package: "Licensable"),
-                .product(name: "SelectableCollectionViewMacResources",
-                         package: "MacResources",
-                         condition: .when(platforms: [.macOS])),
             ],
             resources: [.process("Resources")]),
         .testTarget(

Sources/SelectableCollectionView/Model/CollectionViewProxy.swift

@@ -20,6 +20,8 @@
 
 import SwiftUI
 
+
+// TODO: We need a decoupling proxy if we're not going to have memory leaks
 /**
  * Proxy protocol for managing a collection view.
  *

Sources/SelectableCollectionView/Views/CollectionViewCell.swift

@@ -0,0 +1,103 @@
+// Copyright (c) 2022-2026 Jason Morley
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#if os(macOS)
+
+import SwiftUI
+
+class CollectionViewCell<ID: Hashable, Content: View>: NSCollectionViewItem {
+
+    static var identifier: NSUserInterfaceItemIdentifier {
+        return NSUserInterfaceItemIdentifier(rawValue: "CollectionViewCell")
+    }
+
+    private var hostingView: NSHostingView<CollectionViewCellContent<ID, Content>>?
+    private var id: ID?
+    private var content: Content?
+    private var parentHasFocus: Bool = false
+    private var parentIsKey: Bool = false
+
+    override var isSelected: Bool {
+        didSet {
+            updateState()
+        }
+    }
+
+    override var highlightState: NSCollectionViewItem.HighlightState {
+        didSet {
+            updateState()
+        }
+    }
+
+    override func loadView() {
+        view = NSView()
+    }
+
+    func configure(_ content: Content?, id: ID?, parentHasFocus: Bool, parentIsKey: Bool) {
+        self.content = content
+        self.id = id
+        self.parentHasFocus = parentHasFocus
+        self.parentIsKey = parentIsKey
+        host()
+    }
+
+    private func updateState() {
+        host()
+    }
+
+    private func host() {
+
+        guard content != nil || hostingView != nil else {
+            return
+        }
+
+        let selectionColor = parentHasFocus && parentIsKey
+            ? Color(nsColor: .selectedContentBackgroundColor)
+            : Color(nsColor: .unemphasizedSelectedContentBackgroundColor)
+        let rootView = CollectionViewCellContent(id: id,
+                                                content: content,
+                                                isSelected: isSelected,
+                                                highlightState: .init(highlightState),
+                                                selectionColor: selectionColor)
+
+        guard let hostingView else {
+            let hostingView = NSHostingView(rootView: rootView)
+            hostingView.translatesAutoresizingMaskIntoConstraints = false
+            view.addSubview(hostingView)
+            NSLayoutConstraint.activate([
+                hostingView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+                hostingView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+                hostingView.topAnchor.constraint(equalTo: view.topAnchor),
+                hostingView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
+            ])
+            self.hostingView = hostingView
+            return
+        }
+        hostingView.rootView = rootView
+    }
+
+    override func prepareForReuse() {
+        super.prepareForReuse()
+        configure(nil, id: nil, parentHasFocus: false, parentIsKey: false)
+    }
+
+}
+
+#endif

Sources/SelectableCollectionView/Views/CollectionViewCellContent.swift

@@ -0,0 +1,45 @@
+// Copyright (c) 2022-2026 Jason Morley
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#if os(macOS)
+
+import SwiftUI
+
+struct CollectionViewCellContent<ID: Hashable, Content: View>: View {
+
+    let id: ID?
+    let content: Content?
+    let isSelected: Bool
+    let highlightState: CollectionViewItemHighlightState
+    let selectionColor: Color
+
+    var body: some View {
+        if let content, let id {
+            content
+                .environment(\.isSelected, isSelected)
+                .environment(\.highlightState, highlightState)
+                .environment(\.selectionColor, selectionColor)
+                .id(id)
+        }
+    }
+
+}
+
+#endif

Sources/SelectableCollectionView/Views/CollectionViewContainer.swift

@@ -24,8 +24,6 @@ import Carbon
 import Combine
 import SwiftUI
 
-import SelectableCollectionViewMacResources
-
 public protocol CollectionViewContainerDelegate: NSObject {
 
     associatedtype Element: Identifiable
@@ -67,7 +65,7 @@ public class CollectionViewContainer<Element: Identifiable, Content: View, Deleg
 
     typealias Snapshot = NSDiffableDataSourceSnapshot<Section, Element.ID>
     typealias DataSource = NSCollectionViewDiffableDataSource<Section, Element.ID>
-    typealias Cell = ShortcutItemView
+    typealias Cell = CollectionViewCell<Element.ID, Content>
 
     private let scrollView: CustomScrollView
     private let collectionView: InteractiveCollectionView
@@ -90,17 +88,26 @@ public class CollectionViewContainer<Element: Identifiable, Content: View, Deleg
         super.init(frame: .zero)
 
         dataSource = DataSource(collectionView: collectionView) { [weak self] collectionView, indexPath, id in
+            guard let view = collectionView.makeItem(withIdentifier: Cell.identifier,
+                                                     for: indexPath) as? Cell else {
+                return Cell()
+            }
             guard let self,
                   let item = self.items[id],
-                  let view = collectionView.makeItem(withIdentifier: ShortcutItemView.identifier, for: indexPath) as? ShortcutItemView,
                   let content = self.delegate?.collectionViewContainer(self, contentForElement: item)
             else {
-                return ShortcutItemView()
+                // Explicitly empty the cell. It may have been recycled, in which case returning it untouched would
+                // leave it showing the previous element's content.
+                view.configure(nil,
+                               id: nil,
+                               parentHasFocus: collectionView.isFirstResponder,
+                               parentIsKey: collectionView.window?.isKeyWindow ?? false)
+                return view
             }
-            view.configure(AnyView(content),
+            view.configure(content,
+                           id: id,
                            parentHasFocus: collectionView.isFirstResponder,
                            parentIsKey: collectionView.window?.isKeyWindow ?? false)
-            view.element = item
             return view
         }
 
@@ -117,9 +124,7 @@ public class CollectionViewContainer<Element: Identifiable, Content: View, Deleg
         collectionView.delegate = self
         collectionView.interactionDelegate = self
 
-        let itemNib = NSNib(nibNamed: "ShortcutItemView", bundle: Resources.bundle)
-        collectionView.register(itemNib, forItemWithIdentifier: ShortcutItemView.identifier)
-        collectionView.register(ShortcutItemView.self, forItemWithIdentifier: ShortcutItemView.identifier)
+        collectionView.register(Cell.self, forItemWithIdentifier: Cell.identifier)
 
         collectionView.isSelectable = true
         collectionView.allowsMultipleSelection = true
@@ -141,16 +146,20 @@ public class CollectionViewContainer<Element: Identifiable, Content: View, Deleg
         fatalError("init(coder:) has not been implemented")
     }
 
-    // TODO: Take in a set of items to compare with and we can maybe do an intersection?
+    // TODO: Is it possible to restrict this to just the cells that have changed?
     func updateVisibleItems() {
         // Update the hosted item content.
         for item in collectionView.visibleItems() {
-            guard let item = item as? ShortcutItemView,
-                  let element = item.element as? Element else {
+            guard let item = item as? Cell,
+                  let indexPath = collectionView.indexPath(for: item),
+                  let id = dataSource?.itemIdentifier(for: indexPath),
+                  let element = items[id],
+                  let content = delegate?.collectionViewContainer(self, contentForElement: element)
+            else {
                 continue
             }
-            let content = self.delegate?.collectionViewContainer(self, contentForElement: element)
-            item.configure(AnyView(content),
+            item.configure(content,
+                           id: id,
                            parentHasFocus: collectionView.isFirstResponder,
                            parentIsKey: collectionView.window?.isKeyWindow ?? false)
         }
@@ -280,7 +289,8 @@ public class CollectionViewContainer<Element: Identifiable, Content: View, Deleg
         dispatchPrecondition(condition: .onQueue(.main))
 
         // Cache the items.
-        for item in items {
+        self.items.removeAll()
+        for item in items {	
             self.items[item.id] = item
         }
 
@@ -290,7 +300,7 @@ public class CollectionViewContainer<Element: Identifiable, Content: View, Deleg
         snapshot.appendItems(items.map({ $0.id }), toSection: Section.none)
         dataSource.apply(snapshot, animatingDifferences: true)
 
-        // TODO: Update the selection?
+        // TODO: Update the selection and the currently selected coordinate.
     }
 
     public func insertItem(_ item: Element, atIndex index: Int, items: [Element]) {