Forward Opt+Enter as ESC+CR to alt-screen programs on macOS

crates/warp_terminal/src/model/escape_sequences.rs

@@ -551,6 +551,7 @@ fn cursor_movement_keystroke_to_escape_sequence(
 fn map_special_key_to_bytes(key: &str) -> Option<&[u8]> {
     match key {
         "backspace" => Some("\x7f".as_bytes()),
+        "enter" => Some("\r".as_bytes()),
         "insert" => Some("\x1b[2~".as_bytes()),
         "delete" => Some("\x1b[3~".as_bytes()),
         "pageup" => Some("\x1b[5~".as_bytes()),
@@ -567,9 +568,13 @@ fn meta_keystroke_to_escape_sequence(
     _mode_provider: &impl ModeProvider,
 ) -> Option<Vec<u8>> {
     // On mac, we have a setting that allows users to map the Option keys to
-    // meta.
+    // meta. When that setting is off, Option+letter produces special glyphs
+    // (Option+E = é, etc.), so we don't treat alt as meta by default. The
+    // exception is Enter, which never has an Option-modified glyph — TUIs like
+    // claude/vim/fish expect Option+Enter to arrive as ESC+CR (xterm
+    // convention), so we let alt-enter through here too.
     if OperatingSystem::get().is_mac() {
-        if !keystroke.meta {
+        if !keystroke.meta && !(keystroke.alt && keystroke.key == "enter") {
             return None;
         }
     } else {

crates/warp_terminal/src/model/escape_sequences_test.rs

@@ -463,12 +463,34 @@ fn test_meta_keystroke_to_escape_sequence() {
             Keystroke::parse(metaify("'")).unwrap(),
             vec![C0::ESC, b'\''],
         ),
+        (
+            Keystroke::parse(metaify("enter")).unwrap(),
+            vec![C0::ESC, b'\r'],
+        ),
     ];
 
     let terminal_model_mock = TerminalModelMock::new();
     validate_keystroke_test_cases(test_cases, &terminal_model_mock);
 }
 
+/// On macOS, Option+Enter must encode as ESC+CR even when the user has not
+/// enabled Option-as-Meta. Without this, the bare `\r` falls through to the
+/// PTY and TUIs like claude/vim/fish treat it as plain Enter (submit) rather
+/// than the Alt+Enter sequence they expect for inserting a newline.
+#[test]
+fn test_alt_enter_on_mac_yields_esc_cr_without_option_as_meta() {
+    if !OperatingSystem::get().is_mac() {
+        return;
+    }
+    let test_cases: &[(Keystroke, Vec<u8>)] = &[(
+        Keystroke::parse("alt-enter").unwrap(),
+        vec![C0::ESC, b'\r'],
+    )];
+
+    let terminal_model_mock = TerminalModelMock::new();
+    validate_keystroke_test_cases(test_cases, &terminal_model_mock);
+}
+
 #[test]
 fn test_unmatched_keystroke_does_not_yield_escape_sequence() {
     let test_cases: &[Keystroke] = &[