feat: Add btw alias for side slash command (#23592)

codex-rs/tui/src/chatwidget/tests/side.rs

@@ -173,6 +173,59 @@ async fn slash_side_is_rejected_during_review_mode() {
     );
 }
 
+#[tokio::test]
+async fn slash_btw_is_rejected_during_review_mode() {
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
+    chat.review.is_review_mode = true;
+
+    chat.dispatch_command(SlashCommand::Btw);
+
+    let event = rx
+        .try_recv()
+        .expect("expected review-mode btw conversation error");
+    match event {
+        AppEvent::InsertHistoryCell(cell) => {
+            let rendered = lines_to_single_string(&cell.display_lines(/*width*/ 80));
+            assert!(
+                rendered.contains("'/btw' is unavailable while code review is running."),
+                "expected review-mode btw conversation error, got {rendered:?}"
+            );
+        }
+        other => panic!("expected InsertHistoryCell error, got {other:?}"),
+    }
+    assert!(rx.try_recv().is_err(), "expected no follow-up events");
+    assert!(
+        op_rx.try_recv().is_err(),
+        "expected no side conversation op"
+    );
+}
+
+#[tokio::test]
+async fn slash_btw_is_rejected_before_the_session_starts() {
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
+
+    chat.dispatch_command(SlashCommand::Btw);
+
+    let event = rx
+        .try_recv()
+        .expect("expected pre-session btw conversation error");
+    match event {
+        AppEvent::InsertHistoryCell(cell) => {
+            let rendered = lines_to_single_string(&cell.display_lines(/*width*/ 80));
+            assert!(
+                rendered.contains("'/btw' is unavailable before the session starts."),
+                "expected pre-session btw conversation error, got {rendered:?}"
+            );
+        }
+        other => panic!("expected InsertHistoryCell error, got {other:?}"),
+    }
+    assert!(rx.try_recv().is_err(), "expected no follow-up events");
+    assert!(
+        op_rx.try_recv().is_err(),
+        "expected no side conversation op"
+    );
+}
+
 #[tokio::test]
 async fn submit_user_message_as_plain_user_turn_does_not_run_shell_commands() {
     let (mut chat, _rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
@@ -219,6 +272,31 @@ async fn slash_side_without_args_starts_empty_side_conversation() {
     assert!(chat.input_queue.queued_user_messages.is_empty());
 }
 
+#[tokio::test]
+async fn slash_btw_without_args_starts_empty_side_conversation() {
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
+    let parent_thread_id = ThreadId::new();
+    chat.thread_id = Some(parent_thread_id);
+    chat.on_task_started();
+    chat.bottom_pane
+        .set_composer_text("/btw".to_string(), Vec::new(), Vec::new());
+
+    chat.handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
+
+    assert_matches!(
+        rx.try_recv(),
+        Ok(AppEvent::StartSide {
+            parent_thread_id: emitted_parent_thread_id,
+            user_message: None,
+        }) if emitted_parent_thread_id == parent_thread_id
+    );
+    assert!(
+        op_rx.try_recv().is_err(),
+        "bare /btw should not submit an op on the parent thread"
+    );
+    assert!(chat.input_queue.queued_user_messages.is_empty());
+}
+
 #[tokio::test]
 async fn slash_side_requests_forked_side_question_while_task_running() {
     let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
@@ -268,6 +346,41 @@ async fn slash_side_requests_forked_side_question_while_task_running() {
     );
 }
 
+#[tokio::test]
+async fn slash_btw_requests_forked_side_question_while_task_running() {
+    let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;
+    let parent_thread_id = ThreadId::new();
+    chat.thread_id = Some(parent_thread_id);
+    chat.on_task_started();
+    chat.bottom_pane.set_composer_text(
+        "/btw explore the codebase".to_string(),
+        Vec::new(),
+        Vec::new(),
+    );
+
+    chat.handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
+
+    assert_matches!(
+        rx.try_recv(),
+        Ok(AppEvent::StartSide {
+            parent_thread_id: emitted_parent_thread_id,
+            user_message: Some(user_message),
+        }) if emitted_parent_thread_id == parent_thread_id
+            && user_message
+                == UserMessage {
+                    text: "explore the codebase".to_string(),
+                    local_images: Vec::new(),
+                    remote_image_urls: Vec::new(),
+                    text_elements: Vec::new(),
+                    mention_bindings: Vec::new(),
+                }
+    );
+    assert!(
+        op_rx.try_recv().is_err(),
+        "expected no op on the parent thread"
+    );
+}
+
 #[tokio::test]
 async fn side_context_label_preserves_status_line_snapshot() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual(/*model_override*/ None).await;