fix: preserve shift-enter in windows panes (#1909)

refs #1743

2 files changed, 83 insertions, 8 deletions

diff --git a/src/pane/kitty_keyboard.rs b/src/pane/kitty_keyboard.rs
index 89824ee3..30ab62ba 100644
--- a/src/pane/kitty_keyboard.rs
+++ b/src/pane/kitty_keyboard.rs
@@ -3,6 +3,8 @@ pub(crate) struct KittyKeyboardTracker {
     pending: Vec<u8>,
     stack: Vec<u16>,
     flags: u16,
+    #[cfg(windows)]
+    modify_other_keys: bool,
 }
 
 impl KittyKeyboardTracker {
@@ -30,6 +32,10 @@ impl KittyKeyboardTracker {
                 self.store_pending(&bytes[index..]);
                 break;
             }
+            #[cfg(windows)]
+            if bytes[index + 1] == b'c' {
+                self.modify_other_keys = false;
+            }
             if bytes[index + 1] != b'[' {
                 index += 1;
                 continue;
@@ -44,13 +50,52 @@ impl KittyKeyboardTracker {
                 break;
             }
 
-            if bytes[end] == b'u' {
-                self.observe_csi_u(&bytes[index + 2..end]);
+            match bytes[end] {
+                b'u' => self.observe_csi_u(&bytes[index + 2..end]),
+                #[cfg(windows)]
+                b'm' => self.observe_modify_other_keys(&bytes[index + 2..end]),
+                #[cfg(windows)]
+                b'n' if bytes[index + 2..end]
+                    .strip_prefix(b">")
+                    .is_some_and(|params| {
+                        !params.contains(&b';') && parse_kitty_keyboard_flags(params) == 4
+                    }) =>
+                {
+                    self.modify_other_keys = false;
+                }
+                _ => {}
             }
             index = end + 1;
         }
     }
 
+    #[cfg(windows)]
+    pub(crate) fn modify_other_keys_enabled(&self) -> bool {
+        self.modify_other_keys
+    }
+
+    #[cfg(windows)]
+    fn observe_modify_other_keys(&mut self, params: &[u8]) {
+        let Some(params) = params.strip_prefix(b">") else {
+            return;
+        };
+        if params.is_empty() {
+            self.modify_other_keys = false;
+            return;
+        }
+
+        let mut parts = params.split(|byte| *byte == b';');
+        let resource = parts.next().unwrap_or_default();
+        let value = parts.next();
+        if parts.next().is_some() {
+            return;
+        }
+        if parse_kitty_keyboard_flags(resource) == 4 {
+            self.modify_other_keys =
+                value.is_some_and(|value| parse_kitty_keyboard_flags(value) != 0);
+        }
+    }
+
     fn store_pending(&mut self, bytes: &[u8]) {
         self.pending.clear();
         if bytes.len() <= 64 {
@@ -115,11 +160,19 @@ mod tests {
     fn buffers_split_csi_sequences() {
         let mut tracker = KittyKeyboardTracker::default();
 
-        tracker.observe(b"\x1b[>1u\x1b[>5");
-        tracker.observe(b"u\x1b[<");
+        tracker.observe(b"\x1b[>1u\x1b[>4;");
+        tracker.observe(b"01m\x1b[>5u\x1b[<");
         tracker.observe(b"u");
 
         assert_eq!(tracker.flags, 1);
         assert_eq!(tracker.stack, vec![0]);
+        #[cfg(windows)]
+        {
+            assert!(tracker.modify_other_keys_enabled());
+            tracker.observe(b"\x1b[>1m");
+            assert!(tracker.modify_other_keys_enabled());
+            tracker.observe(b"\x1b[>04n");
+            assert!(!tracker.modify_other_keys_enabled());
+        }
     }
 }
diff --git a/src/pane/terminal.rs b/src/pane/terminal.rs
index d5070b9b..76ab20d3 100644
--- a/src/pane/terminal.rs
+++ b/src/pane/terminal.rs
@@ -1286,6 +1286,8 @@ impl GhosttyPaneTerminal {
         let Ok(mut core) = self.core.lock() else {
             return;
         };
+        #[cfg(windows)]
+        core.kitty_keyboard.observe(ansi.as_bytes());
         core.terminal.write(ansi.as_bytes());
         #[cfg(windows)]
         windows_recent_fallback::update(&mut core);
@@ -1565,6 +1567,9 @@ impl GhosttyPaneTerminal {
             mouse_protocol_mode,
             mouse_protocol_encoding,
             mouse_alternate_scroll,
+            #[cfg(windows)]
+            modify_other_keys: core.kitty_keyboard.modify_other_keys_enabled(),
+            #[cfg(not(windows))]
             modify_other_keys: core
                 .terminal
                 .keyboard_state_ansi()
@@ -1619,6 +1624,18 @@ impl GhosttyPaneTerminal {
         key: crate::input::TerminalKey,
         protocol: crate::input::KeyboardProtocol,
     ) -> Vec<u8> {
+        #[cfg(windows)]
+        if let Some(bytes) = crate::platform::encode_windows_conpty_shift_enter(key) {
+            if self.core.lock().is_ok_and(|core| {
+                core.terminal
+                    .kitty_keyboard_flags()
+                    .is_ok_and(|flags| flags == 0)
+                    && !core.kitty_keyboard.modify_other_keys_enabled()
+            }) {
+                return bytes;
+            }
+        }
+
         if ghostty_prefers_herdr_text_encoding(key) {
             return crate::input::encode_terminal_key(key, protocol);
         }
@@ -3967,11 +3984,16 @@ mod tests {
     fn ghostty_modify_other_keys_mode_one_preserves_shift_enter() {
         let (tx, _rx) = mpsc::channel(4);
         let terminal = crate::ghostty::Terminal::new(80, 24, 0).unwrap();
-        let pane = GhosttyPaneTerminal::new(terminal, tx.clone()).unwrap();
-        let pane_id = PaneId::from_raw(1);
-        pane.process_pty_bytes(pane_id, 0, b"\x1b[>4;1m", &tx);
-
+        let pane = GhosttyPaneTerminal::new(terminal, tx).unwrap();
         let key = crate::input::parse_terminal_key_sequence("\x1b[13;2u").unwrap();
+
+        #[cfg(windows)]
+        assert_eq!(
+            pane.encode_terminal_key(key, crate::input::KeyboardProtocol::Legacy),
+            b"\x1b[13;28;13;1;16;1_"
+        );
+
+        pane.seed_history_ansi("\x1b[>4;1m");
         let encoded = pane.encode_terminal_key(key, crate::input::KeyboardProtocol::Legacy);
 
         assert_eq!(encoded, b"\x1b[27;2;13~");