Fix Korean 2-Set terminal arrows

Sources/AppDelegate.swift

@@ -14710,7 +14710,7 @@ private extension NSWindow {
             // process it. Cmd-based shortcuts should still work during composition since
             // Cmd is never part of IME input sequences.
             if ghosttyView.hasMarkedText(), !event.modifierFlags.intersection(.deviceIndependentFlagsMask).contains(.command) {
-                return cmux_performKeyEquivalent(with: event)
+                return false
             }
 
             let flags = event.modifierFlags.intersection(.deviceIndependentFlagsMask)

Sources/GhosttyNSView+IMEComposition.swift

@@ -1,6 +1,13 @@
 import AppKit
+import Carbon.HIToolbox
 
 extension GhosttyNSView {
+    // Issue #4093 is specifically Korean 2-Set. Other Korean layouts should be
+    // validated separately before this allow-list is broadened.
+    private static let korean2SetInputSourceIDs: Set<String> = [
+        "com.apple.inputmethod.Korean.2SetKorean",
+    ]
+
     /// Clamps AppKit's marked-text selection into the active preedit buffer.
     func normalizedMarkedSelectionRange(_ range: NSRange, markedLength: Int) -> NSRange {
         guard markedLength > 0 else {
@@ -33,7 +40,9 @@ extension GhosttyNSView {
     func shouldSuppressGhosttyKeyForwardingAfterIMEHandling(
         before: (text: String, selection: NSRange),
         after: (text: String, selection: NSRange),
-        accumulatedText: [String]
+        accumulatedText: [String],
+        event: NSEvent? = nil,
+        inputSourceId: String? = nil
     ) -> Bool {
         guard accumulatedText.isEmpty else { return false }
 
@@ -45,7 +54,107 @@ extension GhosttyNSView {
             return true
         }
 
-        return before.selection != after.selection
+        if before.selection != after.selection {
+            return !shouldForwardKoreanMarkedSelectionArrowToTerminal(
+                event: event,
+                inputSourceId: inputSourceId
+            )
+        }
+
+        guard let event, isInputMethodSource(inputSourceId) else {
+            return false
+        }
+        guard !shouldForwardKoreanMarkedSelectionArrowToTerminal(
+            event: event,
+            inputSourceId: inputSourceId
+        ) else {
+            return false
+        }
+        return shouldKeepIMECompositionCommandInsideTextInput(event)
+    }
+
+    private func shouldForwardKoreanMarkedSelectionArrowToTerminal(
+        event: NSEvent?,
+        inputSourceId: String?
+    ) -> Bool {
+        guard let event else { return false }
+        guard isKorean2SetInputSource(inputSourceId) else { return false }
+        guard hasOnlyPlainTextInputModifiers(event) else { return false }
+
+        switch Int(event.keyCode) {
+        case kVK_LeftArrow, kVK_RightArrow:
+            return true
+        default:
+            return false
+        }
+    }
+
+    private func isKorean2SetInputSource(_ inputSourceId: String?) -> Bool {
+        guard let inputSourceId else { return false }
+        return Self.korean2SetInputSourceIDs.contains(inputSourceId)
+    }
+
+    private func isInputMethodSource(_ inputSourceId: String?) -> Bool {
+        guard let inputSourceId else { return false }
+        return inputSourceId.range(
+            of: ".inputmethod.",
+            options: .caseInsensitive,
+            locale: Locale(identifier: "en_US_POSIX")
+        ) != nil
+    }
+
+    private func isBopomofoInputSource(_ inputSourceId: String?) -> Bool {
+        guard let inputSourceId else { return false }
+        let comparisonLocale = Locale(identifier: "en_US_POSIX")
+        return inputSourceId.range(of: "Zhuyin", options: .caseInsensitive, locale: comparisonLocale) != nil
+            || inputSourceId.range(of: "Bopomofo", options: .caseInsensitive, locale: comparisonLocale) != nil
+    }
+
+    private func hasOnlyPlainTextInputModifiers(_ event: NSEvent) -> Bool {
+        let flags = event.modifierFlags
+            .intersection(.deviceIndependentFlagsMask)
+            .subtracting([.numericPad, .function, .capsLock])
+        return flags.isEmpty
+    }
+
+    /// Returns true for active-composition command keys that belong to AppKit's
+    /// text input manager even when marked text itself does not change.
+    private func shouldKeepIMECompositionCommandInsideTextInput(_ event: NSEvent) -> Bool {
+        guard hasOnlyTextInputCommandModifiers(event) else { return false }
+
+        switch Int(event.keyCode) {
+        case kVK_LeftArrow, kVK_RightArrow, kVK_UpArrow, kVK_DownArrow,
+             kVK_PageUp, kVK_PageDown, kVK_Home, kVK_End,
+             kVK_Space, kVK_Return, kVK_ANSI_KeypadEnter, kVK_Escape,
+             kVK_Tab, kVK_Delete, kVK_ForwardDelete:
+            return true
+        default:
+            return false
+        }
+    }
+
+    private func hasOnlyTextInputCommandModifiers(_ event: NSEvent) -> Bool {
+        let flags = event.modifierFlags
+            .intersection(.deviceIndependentFlagsMask)
+            .subtracting([.numericPad, .function, .capsLock])
+        return flags.isEmpty || flags == [.shift]
+    }
+
+    func shouldBufferBopomofoInsertedPreedit(_ text: String, inputSourceId: String? = nil) -> Bool {
+        guard !text.isEmpty else { return false }
+        guard isBopomofoInputSource(inputSourceId ?? KeyboardLayout.id) else { return false }
+        return text.unicodeScalars.allSatisfy(isBopomofoPreeditScalar)
+    }
+
+    private func isBopomofoPreeditScalar(_ scalar: UnicodeScalar) -> Bool {
+        switch scalar.value {
+        case 0x3100...0x312F, 0x31A0...0x31BF:
+            return true
+        case 0x02C7, 0x02C9, 0x02CA, 0x02CB, 0x02D9:
+            return true
+        default:
+            return false
+        }
     }
 
 #if DEBUG
@@ -54,12 +163,16 @@ extension GhosttyNSView {
         markedSelectionBefore: NSRange,
         markedTextAfter: String,
         markedSelectionAfter: NSRange,
-        accumulatedText: [String]
+        accumulatedText: [String],
+        event: NSEvent? = nil,
+        inputSourceId: String? = nil
     ) -> Bool {
         shouldSuppressGhosttyKeyForwardingAfterIMEHandling(
             before: (markedTextBefore, markedSelectionBefore),
             after: (markedTextAfter, markedSelectionAfter),
-            accumulatedText: accumulatedText
+            accumulatedText: accumulatedText,
+            event: event,
+            inputSourceId: inputSourceId
         )
     }
 #endif

Sources/GhosttyTerminalView.swift

@@ -7709,14 +7709,9 @@ class GhosttyNSView: NSView, NSUserInterfaceValidations {
         let markedTextBefore = markedText.length > 0
         let markedStateBefore = (markedText.string, markedSelectedRange)
 
-        // Capture the keyboard layout ID before interpretation so we can
-        // detect if an IME changed it (e.g. toggling input methods).
-        // We only check when not already in a preedit state.
-        let keyboardIdBefore: String? = if (!markedTextBefore) {
-            KeyboardLayout.id
-        } else {
-            nil
-        }
+        // Capture the keyboard layout ID before interpretation so the IME
+        // forwarding decision uses the source that saw this key.
+        let keyboardIdBefore = KeyboardLayout.id
 
         // Let the input system handle the event (for IME, dead keys, etc.)
 #if DEBUG
@@ -7758,12 +7753,20 @@ class GhosttyNSView: NSView, NSUserInterfaceValidations {
 
         let accumulatedText = keyTextAccumulator ?? []
         if shouldSuppressGhosttyKeyForwardingAfterIMEHandling(
-            before: markedStateBefore, after: (markedText.string, markedSelectedRange), accumulatedText: accumulatedText
+            before: markedStateBefore,
+            after: (markedText.string, markedSelectedRange),
+            accumulatedText: accumulatedText,
+            event: event,
+            inputSourceId: keyboardIdBefore
         ) {
             imeConsumedKeyUps.insert(event.keyCode)
             return
         }
 
+        // A forwarded keyDown owns its keyUp. Clear any stale IME suppression
+        // entry left by an earlier suppressed repeat for the same physical key.
+        imeConsumedKeyUps.remove(event.keyCode)
+
         // Build the key event
         var keyEvent = ghostty_input_key_s()
         keyEvent.action = action
@@ -13204,6 +13207,12 @@ extension GhosttyNSView: NSTextInputClient {
             return
         }
 
+        if keyTextAccumulator != nil,
+           shouldBufferBopomofoInsertedPreedit(chars) {
+            insertBopomofoPreeditText(chars, replacementRange: replacementRange)
+            return
+        }
+
         // Clear marked text since we're inserting
         unmarkText()
 
@@ -13254,6 +13263,32 @@ extension GhosttyNSView: NSTextInputClient {
             preserveLiteralEscape: !isExternalCommittedText
         )
     }
+
+    private func insertBopomofoPreeditText(_ chars: String, replacementRange: NSRange) {
+        let effectiveRange = effectiveBopomofoPreeditReplacementRange(replacementRange)
+        if let range = Range(effectiveRange, in: markedText.string) {
+            let insertionLocation = effectiveRange.location + (chars as NSString).length
+            let next = markedText.string.replacingCharacters(in: range, with: chars)
+            markedText = NSMutableAttributedString(string: next)
+            markedSelectedRange = normalizedMarkedSelectionRange(
+                NSRange(location: insertionLocation, length: 0),
+                markedLength: markedText.length
+            )
+            return
+        }
+
+        markedText.append(NSAttributedString(string: chars))
+        markedSelectedRange = normalizedMarkedSelectionRange(
+            NSRange(location: markedText.length, length: 0),
+            markedLength: markedText.length
+        )
+    }
+
+    private func effectiveBopomofoPreeditReplacementRange(_ replacementRange: NSRange) -> NSRange {
+        guard replacementRange.location == NSNotFound else { return replacementRange }
+        guard markedText.length > 0 else { return NSRange(location: 0, length: 0) }
+        return normalizedMarkedSelectionRange(markedSelectedRange, markedLength: markedText.length)
+    }
 }
 
 // MARK: - SwiftUI Wrapper