fix

crates/pikl-gui/src/lib.rs

@@ -177,7 +177,12 @@ fn setup_bridge(
     action_tx: mpsc::Sender<ModifiedAction>,
     event_rx: broadcast::Receiver<MenuEvent>,
 ) {
-    let _ = action_tx.blocking_send(ModifiedAction::new(Action::Resize {
+    // try_send rather than blocking_send: this is the first
+    // message on a fresh channel so it always has capacity,
+    // and try_send works regardless of whether we're inside
+    // a tokio runtime context (macOS calls this from the
+    // main thread outside block_on).
+    let _ = action_tx.try_send(ModifiedAction::new(Action::Resize {
         height: VIEWPORT_HEIGHT,
     }));
 

crates/pikl/src/main.rs

@@ -365,14 +365,23 @@ fn main() {
     });
 
     // STEP 4: Branch on headless vs interactive
+    #[cfg(unix)]
+    let saved_fd = saved_stdin_fd;
+    #[cfg(not(unix))]
+    let saved_fd: Option<i32> = None;
+
     let result = if let Some(script) = script {
         rt.block_on(run_headless(items, &cli, script, start_mode, column_config))
+    } else if cfg!(target_os = "macos") && frontend_mode == FrontendMode::Gui {
+        // macOS requires the GUI event loop on the main thread
+        // (AppKit/winit constraint). We can't run it inside
+        // block_on, so the GUI gets the main thread and tokio
+        // work is spawned onto the runtime's worker threads.
+        run_gui_main_thread(
+            &rt, items, &cli, start_mode, column_config, streaming, saved_fd,
+        )
     } else {
         let history_entries = history.as_ref().map(|h| h.entries().to_vec());
-        #[cfg(unix)]
-        let saved_fd = saved_stdin_fd;
-        #[cfg(not(unix))]
-        let saved_fd: Option<i32> = None;
         rt.block_on(run_interactive(
             items,
             &cli,
@@ -662,13 +671,11 @@ async fn run_interactive(
             result
         }
         FrontendMode::Gui => {
-            // GUI runs on the main thread (Wayland requirement).
             // Spawn the core event loop on a background task.
             let menu_handle = tokio::spawn(menu.run());
 
-            // pikl_gui::run blocks until the user confirms/cancels.
-            // Run it on a blocking thread so we don't stall the
-            // tokio runtime.
+            // On Linux, spawn_blocking is fine since Wayland doesn't
+            // have the main-thread restriction.
             let gui_handle = tokio::task::spawn_blocking(move || {
                 pikl_gui::run(action_tx, event_rx)
                     .map_err(|e| PiklError::Io(std::io::Error::other(e.to_string())))
@@ -687,6 +694,133 @@ async fn run_interactive(
     }
 }
 
+/// Run GUI on the main thread for macOS. AppKit requires
+/// the event loop on the main thread, so we can't use
+/// block_on (which would nest the iced event loop inside
+/// tokio's reactor). Instead, spawn all background work
+/// onto the runtime's worker threads and run the GUI
+/// directly.
+fn run_gui_main_thread(
+    rt: &tokio::runtime::Runtime,
+    items: Vec<Item>,
+    cli: &Cli,
+    start_mode: Mode,
+    column_config: Option<ColumnConfig>,
+    streaming: bool,
+    saved_stdin_fd: Option<i32>,
+) -> Result<MenuResult, PiklError> {
+    let (mut menu, action_tx) = MenuRunner::new(build_menu(items, cli, column_config));
+    menu.set_initial_mode(start_mode);
+    menu.set_multi(cli.multi);
+    menu.set_selection_order(cli.selection_order);
+    menu.set_streaming(streaming);
+
+    if let Some((_handler, dispatcher)) = build_hook_handler(cli, &action_tx) {
+        menu.set_dispatcher(dispatcher);
+    }
+
+    let event_rx = menu.subscribe();
+
+    // Start IPC server if requested
+    let _ipc_server = if cli.ipc {
+        let sock_path = ipc::socket_path(cli.session.as_deref())?;
+        let server = ipc::server::IpcServer::new(
+            sock_path,
+            action_tx.clone(),
+            menu.event_sender(),
+        );
+        let ipc_event_rx = menu.subscribe();
+        server.start(ipc_event_rx).map_err(PiklError::Io)?;
+        Some(server)
+    } else {
+        None
+    };
+
+    // Enter the runtime context so tokio::spawn works
+    // without being inside block_on.
+    let _guard = rt.enter();
+
+    // Signal handler
+    let signal_tx = action_tx.clone();
+    tokio::spawn(async move {
+        match tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate()) {
+            Ok(mut sigterm) => {
+                tokio::select! {
+                    _ = tokio::signal::ctrl_c() => {}
+                    _ = sigterm.recv() => {}
+                }
+            }
+            Err(e) => {
+                tracing::warn!(%e, "failed to register SIGTERM handler, falling back to SIGINT only");
+                let _ = tokio::signal::ctrl_c().await;
+            }
+        }
+        let _ = signal_tx.send(ModifiedAction::new(Action::Cancel)).await;
+    });
+
+    // Streaming stdin reader
+    if let Some(fd) = saved_stdin_fd {
+        let stream_tx = action_tx.clone();
+        tokio::task::spawn_blocking(move || {
+            #[cfg(unix)]
+            {
+                use std::io::BufRead;
+                use std::os::unix::io::FromRawFd;
+
+                let file = unsafe { std::fs::File::from_raw_fd(fd) };
+                let mut reader = std::io::BufReader::new(file);
+                let mut batch = Vec::with_capacity(100);
+                let mut line = String::new();
+
+                loop {
+                    line.clear();
+                    match reader.read_line(&mut line) {
+                        Ok(0) => break,
+                        Ok(_) => {
+                            let trimmed = line.trim_end();
+                            if !trimmed.is_empty() {
+                                batch.push(parse_line_to_value(trimmed));
+                            }
+                            if (batch.len() >= 100 || reader.buffer().is_empty())
+                                && !batch.is_empty()
+                            {
+                                let _ = stream_tx.blocking_send(ModifiedAction::new(
+                                    Action::AddItems(std::mem::take(&mut batch)),
+                                ));
+                            }
+                        }
+                        Err(e) => {
+                            tracing::warn!(%e, "stdin read error");
+                            break;
+                        }
+                    }
+                }
+                if !batch.is_empty() {
+                    let _ =
+                        stream_tx.blocking_send(ModifiedAction::new(Action::AddItems(batch)));
+                }
+                let _ =
+                    stream_tx.blocking_send(ModifiedAction::new(Action::StreamingDone));
+            }
+        });
+    }
+
+    // Core menu on a background task
+    let menu_handle = tokio::spawn(menu.run());
+
+    // GUI on the main thread (the whole point of this function)
+    pikl_gui::run(action_tx, event_rx)
+        .map_err(|e| PiklError::Io(std::io::Error::other(e.to_string())))?;
+
+    // GUI exited. Collect the menu result.
+    rt.block_on(async {
+        match menu_handle.await {
+            Ok(result) => result,
+            Err(e) => Err(PiklError::Io(std::io::Error::other(e.to_string()))),
+        }
+    })
+}
+
 /// Process the menu result: print output to stdout and
 /// exit with the appropriate code.
 fn handle_result(result: Result<MenuResult, PiklError>, cli: &Cli) {