fix(input): preserve shift in kitty alternate reports (#2479)

refs #2435

4 files changed, 71 insertions, 2 deletions

diff --git a/docs/next/CHANGELOG.md b/docs/next/CHANGELOG.md
index e8deca63..277ff405 100644
--- a/docs/next/CHANGELOG.md
+++ b/docs/next/CHANGELOG.md
@@ -9,6 +9,7 @@
 
 ### Fixed
 - macOS `herdr --remote` clients now keep the accepted bridge socket blocking, preventing an immediate disconnect after the protocol handshake. (#2478, thanks @mathijshenquet)
+- Prefix keybindings now preserve Shift in WezTerm Kitty keyboard mode, so commands such as config reload no longer trigger their unshifted action. (#2435)
 - Stable direct installs, self-updates, and remote helper downloads now require and verify the SHA-256 digest published for each GitHub release asset.
 - Configs containing the retired Herdr-written `ui.agent_panel_scope` setting no longer report it as an unknown key after upgrades. (#2292)
 - Claude Code confirmation prompts using `Enter to confirm · Esc to cancel` now report `blocked` instead of `idle`. (#2268)
diff --git a/src/app/input/navigate.rs b/src/app/input/navigate.rs
index 68941e66..1c892028 100644
--- a/src/app/input/navigate.rs
+++ b/src/app/input/navigate.rs
@@ -1901,7 +1901,12 @@ mod tests {
     use super::super::{state_with_workspaces, unique_temp_path};
     use super::*;
     use crate::{
-        app::App, config::Config, input::TerminalKey, terminal::TerminalState, workspace::Workspace,
+        app::App,
+        config::Config,
+        input::TerminalKey,
+        raw_input::{parse_raw_input_bytes_sync, RawInputEvent},
+        terminal::TerminalState,
+        workspace::Workspace,
     };
 
     fn mark_worktree_space_member(state: &mut AppState, ws_idx: usize, key: &str) {
@@ -2841,6 +2846,35 @@ command = "printf literal > '{}'"
     }
 
     #[tokio::test]
+    async fn kitty_shifted_alternate_without_modifier_prefers_reload_over_resize() {
+        let (_api_tx, api_rx) = tokio::sync::mpsc::unbounded_channel();
+        let mut app = App::new(
+            &Config::default(),
+            true,
+            None,
+            api_rx,
+            crate::api::EventHub::default(),
+        );
+        app.state.workspaces = vec![Workspace::test_new("test")];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.mode = Mode::Prefix;
+
+        let mut events = parse_raw_input_bytes_sync(b"\x1b[114:82;1u");
+        assert_eq!(events.len(), 1);
+        let RawInputEvent::Key(key) = events.remove(0) else {
+            panic!("expected key event");
+        };
+        assert_eq!(
+            action_for_key(&app.state, key.clone(), BindingDispatch::Prefix),
+            Some(NavigateAction::ReloadConfig)
+        );
+        app.handle_prefix_key(key);
+
+        assert_eq!(app.state.mode, Mode::Terminal);
+    }
+
+    #[tokio::test]
     async fn legacy_uppercase_prefers_shifted_reload_binding_over_unshifted() {
         let (_api_tx, api_rx) = tokio::sync::mpsc::unbounded_channel();
         let mut app = App::new(
diff --git a/src/input/parse.rs b/src/input/parse.rs
index 861280dd..085757c3 100644
--- a/src/input/parse.rs
+++ b/src/input/parse.rs
@@ -39,8 +39,17 @@ fn parse_kitty_key_sequence(data: &str) -> Option<TerminalKey> {
 
     let code = kitty_codepoint_to_keycode(codepoint)?;
     let kind = parse_kitty_event_type(event_type)?;
+    let mut modifiers = key_modifiers_from_u8(modifier);
+    // Kitty permits the shifted alternate only while Shift is active. Normalize
+    // contradictory reports here so they cannot dispatch an unshifted command.
+    if matches!(code, KeyCode::Char(_))
+        && shifted_codepoint
+            .is_some_and(|shifted| shifted != codepoint && char::from_u32(shifted).is_some())
+    {
+        modifiers |= KeyModifiers::SHIFT;
+    }
 
-    let mut key = TerminalKey::new(code, key_modifiers_from_u8(modifier)).with_kind(kind);
+    let mut key = TerminalKey::new(code, modifiers).with_kind(kind);
     if let Some(shifted_codepoint) = shifted_codepoint {
         key = key.with_shifted_codepoint(shifted_codepoint);
     }
@@ -599,6 +608,30 @@ mod tests {
     }
 
     #[test]
+    fn parse_kitty_sequence_recovers_omitted_shift_modifier() {
+        for (sequence, kind) in [
+            ("\x1b[114:82;1u", crossterm::event::KeyEventKind::Press),
+            ("\x1b[114:82;1:2u", crossterm::event::KeyEventKind::Repeat),
+            ("\x1b[114:82;1:3u", crossterm::event::KeyEventKind::Release),
+        ] {
+            let key = parse_terminal_key_sequence(sequence).unwrap();
+            assert_eq!(key.code, KeyCode::Char('r'));
+            assert_eq!(key.modifiers, KeyModifiers::SHIFT);
+            assert_eq!(key.kind, kind);
+            assert_eq!(key.shifted_codepoint, Some('R' as u32));
+        }
+    }
+
+    #[test]
+    fn parse_kitty_sequence_does_not_infer_shift_without_distinct_shifted_alternate() {
+        for sequence in ["\x1b[114;1u", "\x1b[114:114;1u", "\x1b[114::113;1u"] {
+            let key = parse_terminal_key_sequence(sequence).unwrap();
+            assert_eq!(key.code, KeyCode::Char('r'));
+            assert_eq!(key.modifiers, KeyModifiers::empty());
+        }
+    }
+
+    #[test]
     fn parse_kitty_sequence_preserves_non_us_shift_pairs() {
         for (sequence, base, shifted) in [
             ("\x1b[50:34;2:1u", '2', '"'),
diff --git a/tests/fixtures/keyboard_protocol_corpus.tsv b/tests/fixtures/keyboard_protocol_corpus.tsv
index bf9e7ff9..e405326d 100644
--- a/tests/fixtures/keyboard_protocol_corpus.tsv
+++ b/tests/fixtures/keyboard_protocol_corpus.tsv
@@ -16,6 +16,7 @@ modify_other_keys_ctrl_shift_l	1b5b32373b363b3130387e	char:l	control+shift	press
 kitty_alt_backspace	1b5b3132373b3375	backspace	alt	press
 kitty_shift_letter	1b5b3130383a37363b323a3175	char:l	shift	press	76
 kitty_shift_symbol	1b5b34393a33333b323a3175	char:1	shift	press	33
+kitty_omitted_shift_modifier	1b5b3131343a38323b3175	char:r	shift	press	82
 kitty_release_letter	1b5b3130383a37363b323a3375	char:l	shift	release	76
 kitty_keypad_0	1b5b35373339393b3175	char:0	-	press
 kitty_keypad_1	1b5b35373430303b3175	char:1	-	press