fix: crash on resize (#1683)

Without this, resizing the terminal prints "Error: The cursor position
could not be read within a normal duration" and quits the app.

codex-rs/tui/src/app.rs

@@ -88,7 +88,15 @@ impl App<'_> {
         {
             let app_event_tx = app_event_tx.clone();
             std::thread::spawn(move || {
-                while let Ok(event) = crossterm::event::read() {
+                loop {
+                    // This timeout is necessary to avoid holding the event lock
+                    // that crossterm::event::read() acquires. In particular,
+                    // reading the cursor position (crossterm::cursor::position())
+                    // needs to acquire the event lock, and so will fail if it
+                    // can't acquire it within 2 sec. Resizing the terminal
+                    // crashes the app if the cursor position can't be read.
+                    if let Ok(true) = crossterm::event::poll(Duration::from_millis(100)) {
+                        if let Ok(event) = crossterm::event::read() {
                             match event {
                                 crossterm::event::Event::Key(key_event) => {
                                     app_event_tx.send(AppEvent::KeyEvent(key_event));
@@ -123,6 +131,10 @@ impl App<'_> {
                                 }
                             }
                         }
+                    } else {
+                        // Timeout expired, no `Event` is available
+                    }
+                }
             });
         }