macOS: rework for #12712 and #13645 (#13717)

`needleSelection` was introduced in #12712 to select all texts when
syncing pasteboard, the crash happens most on macOS 15 in
`readPasteboardNeedle`. It seems that `objectWillChange` fires
differently there, and it's hard to reproduce on macOS 26/27. I think
guaranteeing from ourside is enough, I believe SwiftUI already as its
own when updating the binding.

**Confirmed with a simple example on macOS 15, it seems a SwiftUI
issue🫪. So I changed the minimal macOS version for text selection to
macOS 26. I don't see an elegant way to fix it.**

<img width="1352" height="849" alt="image"
src="https://github.com/user-attachments/assets/1dfef3f5-ceaa-41dd-bb91-c23dbc5e4ad3"
/>


```swift
struct ContentView: View {
    @State private var text = ""
    @State private var selection: TextSelection?
    var body: some View {
        TextField("Search", text: $text, selection: $selection)
    }
}
```

macos/Sources/Ghostty/Surface View/OSSurfaceView.swift

@@ -117,18 +117,25 @@ extension Ghostty {
 
 extension Ghostty.OSSurfaceView {
     @MainActor class SearchState: ObservableObject {
+
+        /// We should always change needle's text and its selection together
+        struct Needle: Equatable {
+            var text: String
+            var selection: Range<String.Index>?
+
+            static let empty = Needle(text: "", selection: nil)
+        }
+
         /// The pasteboard used to persist the search needle.
         ///
         /// The `.find` pasteboard lets us sync our needle across the system and other find bars.
         private let pasteboard: OSPasteboard
 
-        @Published private(set) var needle: String = ""
+        @Published var needle = Needle.empty
+
         @Published var selected: UInt?
         @Published var total: UInt?
 
-        /// The range of the needle's text selection in the find bar.
-        @Published private(set) var needleSelection: Range<String.Index>?
-
         init(
             from startSearch: Ghostty.Action.StartSearch,
             pasteboard: OSPasteboard = OSPasteboard.find
@@ -144,45 +151,21 @@ extension Ghostty.OSSurfaceView {
 
         /// Replaces the search needle while keeping its selection valid.
         func setNeedle(_ needle: String, selectAll: Bool = false) {
-            if needle != self.needle {
-                // String.Index values are only valid for the string that created
-                // them, so publish a nil selection before changing the string.
-                needleSelection = nil
-                self.needle = needle
-            }
-
-            if selectAll {
-                needleSelection = self.needle.startIndex..<self.needle.endIndex
-            }
-        }
-
-        /// Updates the selection only when both indices are valid for the needle.
-        func setNeedleSelection(_ selection: Range<String.Index>?) {
-            guard let selection else {
-                needleSelection = nil
-                return
-            }
-
-            guard
-                let lowerBound = String.Index(selection.lowerBound, within: needle),
-                let upperBound = String.Index(selection.upperBound, within: needle)
-            else {
-                needleSelection = nil
-                return
-            }
-
-            needleSelection = lowerBound..<upperBound
+            self.needle = .init(
+                text: needle,
+                selection: selectAll ? needle.startIndex..<needle.endIndex : nil
+            )
         }
 
         func readPasteboardNeedle() {
             let pasteboardNeedle = pasteboard.string
-            if let pasteboardNeedle, pasteboardNeedle != needle {
+            if let pasteboardNeedle, pasteboardNeedle != needle.text {
                 setNeedle(pasteboardNeedle, selectAll: true)
             }
         }
 
         func writePasteboardNeedle() {
-            pasteboard.string = needle
+            pasteboard.string = needle.text
         }
     }
 

macos/Sources/Ghostty/Surface View/SurfaceView.swift

@@ -382,14 +382,8 @@ extension Ghostty {
                 HStack(spacing: 4) {
                     BackportSelectionTextField(
                         "Search",
-                        text: Binding(
-                            get: { searchState.needle },
-                            set: { searchState.setNeedle($0) }
-                        ),
-                        selection: Binding(
-                            get: { searchState.needleSelection },
-                            set: { searchState.setNeedleSelection($0) }
-                        )
+                        text: $searchState.needle.text,
+                        selection: $searchState.needle.selection
                     )
                     .textFieldStyle(.plain)
                     .frame(width: 180)
@@ -414,7 +408,7 @@ extension Ghostty {
                                 .padding(.trailing, 8)
                         }
                     }
-                    .onChange(of: searchState.needle) { _ in
+                    .onChange(of: searchState.needle.text) { _ in
                         searchState.writePasteboardNeedle()
                     }
                     .onReceive(
@@ -431,7 +425,7 @@ extension Ghostty {
                     }
 #if canImport(AppKit)
                     .onExitCommand {
-                        if searchState.needle.isEmpty {
+                        if searchState.needle.text.isEmpty {
                             onClose()
                         } else {
                             Ghostty.moveFocus(to: surfaceView)

macos/Sources/Ghostty/Surface View/SurfaceView_AppKit.swift

@@ -48,6 +48,7 @@ extension Ghostty {
                     // needle is less than 3 chars, we debounce it for a few hundred ms to
                     // avoid kicking off expensive searches.
                     searchNeedleCancellable = searchState.$needle
+                        .map(\.text)
                         .removeDuplicates()
                         .map { needle -> AnyPublisher<String, Never> in
                             if needle.isEmpty || needle.count >= 3 {

macos/Sources/Helpers/Backport.swift

@@ -132,8 +132,19 @@ enum BackportNSGlassStyle {
     #endif
 }
 
-/// Backported `TextField` that supports text selection on macOS 15/iOS 18 and up. The `selection`
-/// has no effect on versions below macOS 15/iOS 18.
+/// Backported `TextField` that supports text selection on macOS 26/iOS 18 and up. The `selection`
+/// has no effect on versions below macOS 26/iOS 18.
+///
+/// Although the API is available from macOS 15, we force it to be 26. Because on macOS 15,
+/// SwiftUI will crash when deleting texts, even for this simple example.
+///
+///     struct ContentView: View {
+///         @State private var text = ""
+///         @State private var selection: TextSelection?
+///         var body: some View {
+///             TextField("Search", text: $text, selection: $selection)
+///         }
+///     }
 struct BackportSelectionTextField: View {
     private let titleKey: LocalizedStringKey
     @Binding private var text: String
@@ -150,7 +161,7 @@ struct BackportSelectionTextField: View {
     }
 
     var body: some View {
-        if #available(iOS 18.0, macOS 15, *) {
+        if #available(iOS 18.0, macOS 26, *) {
             TextField(
                 titleKey,
                 text: _text,

macos/Tests/Ghostty/Surface View/SurfaceView+SearchStateTests.swift

@@ -19,7 +19,7 @@ import Testing
             from: StartSearch(c: .init(needle: nil)),
             pasteboard: pasteboard
         )
-        #expect(sut.needle == "pb")
+        #expect(sut.needle.text == "pb")
     }
 
     @Test func init_withEmptyNeedle_readsPasteboardNeedle() {
@@ -28,7 +28,7 @@ import Testing
                 from: StartSearch(c: .init(needle: needle)),
                 pasteboard: pasteboard
             )
-            #expect(sut.needle == "pb")
+            #expect(sut.needle.text == "pb")
         }
     }
 
@@ -38,7 +38,7 @@ import Testing
                 from: StartSearch(c: .init(needle: needle)),
                 pasteboard: pasteboard
             )
-            #expect(sut.needle == "start")
+            #expect(sut.needle.text == "start")
         }
     }
 
@@ -67,25 +67,12 @@ import Testing
             from: StartSearch(c: .init(needle: nil)),
             pasteboard: pasteboard
         )
-        sut.setNeedleSelection(sut.needle.startIndex..<sut.needle.endIndex)
+        sut.needle.selection = sut.needle.text.startIndex..<sut.needle.text.endIndex
 
         sut.setNeedle("x")
 
-        #expect(sut.needle == "x")
-        #expect(sut.needleSelection == nil)
-    }
-
-    @Test func setNeedleSelection_ignoresRangeFromLongerNeedle() {
-        let sut = SearchState(
-            from: StartSearch(c: .init(needle: nil)),
-            pasteboard: pasteboard
-        )
-        let oldNeedle = "abcdefghijklmnopqrstuvwxyz"
-
-        sut.setNeedle("x")
-        sut.setNeedleSelection(oldNeedle.startIndex..<oldNeedle.endIndex)
-
-        #expect(sut.needleSelection == nil)
+        #expect(sut.needle.text == "x")
+        #expect(sut.needle.selection == nil)
     }
 
     @Test func readPasteboardNeedle_whenPasteboardNeedleIsNil() {
@@ -96,7 +83,7 @@ import Testing
         pasteboard.clearContents()
         sut.setNeedle("sut")
         sut.readPasteboardNeedle()
-        #expect(sut.needle == "sut")
+        #expect(sut.needle.text == "sut")
     }
 
     @Test func readPasteboardNeedle_whenPasteboardNeedleIsValid() {
@@ -106,7 +93,7 @@ import Testing
         )
         sut.setNeedle("sut")
         sut.readPasteboardNeedle()
-        #expect(sut.needle == "pb")
+        #expect(sut.needle.text == "pb")
     }
 
     @Test func readPasteboardNeedle_setsNeedleSelectionRange() {
@@ -118,6 +105,6 @@ import Testing
         sut.readPasteboardNeedle()
 
         let expected = "pb".startIndex..<"pb".endIndex
-        #expect(sut.needleSelection == expected)
+        #expect(sut.needle.selection == expected)
     }
 }