feat: interrupt running task on ctrl-z (#1880)

- Arguably a bugfix as previously CTRL-Z didn't do anything.
- Only in TUI mode for now. This may make sense in other modes... to be
researched.
- The TUI runs the terminal in raw mode and the signals arrive as key
events, so we handle CTRL-Z as a key event just like CTRL-C.
- Not adding UI for it as a composer redesign is coming, and we can just
add it then.
- We should follow with CTRL-Z a second time doing the native terminal
action.

codex-rs/tui/src/app.rs

@@ -238,6 +238,16 @@ impl App<'_> {
                                 }
                             }
                         }
+                        KeyEvent {
+                            code: KeyCode::Char('z'),
+                            modifiers: crossterm::event::KeyModifiers::CONTROL,
+                            kind: KeyEventKind::Press,
+                            ..
+                        } => {
+                            if let AppState::Chat { widget } = &mut self.app_state {
+                                widget.on_ctrl_z();
+                            }
+                        }
                         KeyEvent {
                             code: KeyCode::Char('d'),
                             modifiers: crossterm::event::KeyModifiers::CONTROL,

codex-rs/tui/src/chatwidget.rs

@@ -110,6 +110,22 @@ fn create_initial_user_message(text: String, image_paths: Vec<PathBuf>) -> Optio
 }
 
 impl ChatWidget<'_> {
+    fn interrupt_running_task(&mut self) {
+        if self.bottom_pane.is_task_running() {
+            self.active_history_cell = None;
+            self.bottom_pane.clear_ctrl_c_quit_hint();
+            self.submit_op(Op::Interrupt);
+            self.bottom_pane.set_task_running(false);
+            self.bottom_pane.clear_live_ring();
+            self.live_builder = RowBuilder::new(self.live_builder.width());
+            self.current_stream = None;
+            self.stream_header_emitted = false;
+            self.answer_buffer.clear();
+            self.reasoning_buffer.clear();
+            self.content_buffer.clear();
+            self.request_redraw();
+        }
+    }
     fn layout_areas(&self, area: Rect) -> [Rect; 2] {
         Layout::vertical([
             Constraint::Max(
@@ -569,18 +585,7 @@ impl ChatWidget<'_> {
             CancellationEvent::Ignored => {}
         }
         if self.bottom_pane.is_task_running() {
-            self.active_history_cell = None;
+            self.interrupt_running_task();
-            self.bottom_pane.clear_ctrl_c_quit_hint();
-            self.submit_op(Op::Interrupt);
-            self.bottom_pane.set_task_running(false);
-            self.bottom_pane.clear_live_ring();
-            self.live_builder = RowBuilder::new(self.live_builder.width());
-            self.current_stream = None;
-            self.stream_header_emitted = false;
-            self.answer_buffer.clear();
-            self.reasoning_buffer.clear();
-            self.content_buffer.clear();
-            self.request_redraw();
             CancellationEvent::Ignored
         } else if self.bottom_pane.ctrl_c_quit_hint_visible() {
             self.submit_op(Op::Shutdown);
@@ -591,6 +596,10 @@ impl ChatWidget<'_> {
         }
     }
 
+    pub(crate) fn on_ctrl_z(&mut self) {
+        self.interrupt_running_task();
+    }
+
     pub(crate) fn composer_is_empty(&self) -> bool {
         self.bottom_pane.composer_is_empty()
     }