From 702238f0043b3bbc95bd97ba5131eea6e1160e5a Mon Sep 17 00:00:00 2001
From: Akrelion45 <pornotato@gmail.com>
Date: Mon, 17 Nov 2025 04:15:06 +0100
Subject: [PATCH] Fix AltGr/backslash input on Windows Codex terminal (#6720)
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### Summary

- Treat AltGr chords (Ctrl+Alt) as literal character input in the Codex
TUI textarea so Windows terminals that report
    backslash and other characters via AltGr insert correctly.
- Add regression test altgr_ctrl_alt_char_inserts_literal to ensure
Ctrl+Alt char events append the character and
    advance the cursor.

 ### Motivation

On US/UK keyboard layouts, backslash is produced by a plain key, so
Ctrl+Alt handling is never exercised and the
bug isn’t visible. On many non‑US layouts (e.g., German), backslash and
other symbols require AltGr, which terminals
report as Ctrl+Alt+<char>. Our textarea previously filtered these chords
like navigation bindings, so AltGr input was
dropped on affected layouts. This change treats AltGr chords as literal
input so backslash and similar symbols work on
  Windows terminals.

This fixes multiple reported Issues where the \ symbol got cut off.
Like:
C:\Users\Admin
became
C:UsersAdmin

Co-authored-by: Eric Traut <etraut@openai.com>
---
 codex-rs/tui/src/bottom_pane/textarea.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/codex-rs/tui/src/bottom_pane/textarea.rs b/codex-rs/tui/src/bottom_pane/textarea.rs
index cd913b00d..0a7faa4fc 100644
--- a/codex-rs/tui/src/bottom_pane/textarea.rs
+++ b/codex-rs/tui/src/bottom_pane/textarea.rs
@@ -247,6 +247,16 @@ impl TextArea {
             } if modifiers == (KeyModifiers::CONTROL | KeyModifiers::ALT) => {
                 self.delete_backward_word()
             },
+            KeyEvent {
+                code: KeyCode::Char(c),
+                modifiers,
+                ..
+            } if modifiers.contains(KeyModifiers::ALT)
+                && modifiers.contains(KeyModifiers::CONTROL) =>
+            {
+                // AltGr on many keyboards reports as Ctrl+Alt; treat it as a literal char.
+                self.insert_str(&c.to_string());
+            },
             KeyEvent {
                 code: KeyCode::Backspace,
                 modifiers: KeyModifiers::ALT,
@@ -1454,6 +1464,17 @@ mod tests {
         assert_eq!(t.cursor(), 3);
     }
 
+    #[test]
+    fn altgr_ctrl_alt_char_inserts_literal() {
+        let mut t = ta_with("");
+        t.input(KeyEvent::new(
+            KeyCode::Char('c'),
+            KeyModifiers::CONTROL | KeyModifiers::ALT,
+        ));
+        assert_eq!(t.text(), "c");
+        assert_eq!(t.cursor(), 1);
+    }
+
     #[test]
     fn cursor_vertical_movement_across_lines_and_bounds() {
         let mut t = ta_with("short\nloooooooooong\nmid");