fix: forward resize terminal responses

refs #471

4 files changed, 117 insertions, 28 deletions

diff --git a/docs/next/CHANGELOG.md b/docs/next/CHANGELOG.md
index c1ef0939..824e52c5 100644
--- a/docs/next/CHANGELOG.md
+++ b/docs/next/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Fixed
 - Resizing restored panes no longer aborts the server when libghostty-vt reflows a terminal whose pre-resize cursor row is past the new height. (#465)
+- Full-screen TUIs such as Neovim now receive resize-generated terminal responses after Herdr internal pane resizes, so grown panes redraw without waiting for extra input. (#471)
 
 ## [0.6.8] - 2026-06-04
 
diff --git a/src/pane.rs b/src/pane.rs
index 248f5bb1..19556ffe 100644
--- a/src/pane.rs
+++ b/src/pane.rs
@@ -722,11 +722,24 @@ impl PaneRuntimeIo {
         }
     }
 
-    fn resize(&self, rows: u16, cols: u16, cell_width_px: u32, cell_height_px: u32) {
+    fn resize(
+        &self,
+        rows: u16,
+        cols: u16,
+        cell_width_px: u32,
+        cell_height_px: u32,
+        terminal_responses: Vec<Bytes>,
+    ) {
         match self {
             #[cfg(unix)]
             PaneRuntimeIo::Actor(actor) => {
-                actor.resize(rows, cols, cell_width_px, cell_height_px);
+                actor.resize(
+                    rows,
+                    cols,
+                    cell_width_px,
+                    cell_height_px,
+                    terminal_responses,
+                );
             }
             #[cfg(test)]
             PaneRuntimeIo::TestChannel { resize_tx, .. } => {
@@ -1814,9 +1827,16 @@ impl PaneRuntime {
             return;
         }
         self.current_size.set(size);
-        self.terminal
+        let terminal_responses = self
+            .terminal
             .resize(rows, cols, cell_width_px, cell_height_px);
-        self.io.resize(rows, cols, cell_width_px, cell_height_px);
+        self.io.resize(
+            rows,
+            cols,
+            cell_width_px,
+            cell_height_px,
+            terminal_responses,
+        );
     }
 
     pub fn nudge_child_redraw_after_handoff(&self) {
diff --git a/src/pane/terminal.rs b/src/pane/terminal.rs
index 88924d36..f2fceaa8 100644
--- a/src/pane/terminal.rs
+++ b/src/pane/terminal.rs
@@ -146,9 +146,15 @@ impl PaneTerminal {
             .process_pty_bytes(pane_id, shell_pid, bytes, response_writer)
     }
 
-    pub fn resize(&self, rows: u16, cols: u16, cell_width_px: u32, cell_height_px: u32) {
+    pub fn resize(
+        &self,
+        rows: u16,
+        cols: u16,
+        cell_width_px: u32,
+        cell_height_px: u32,
+    ) -> Vec<Bytes> {
         self.ghostty
-            .resize(rows, cols, cell_width_px, cell_height_px);
+            .resize(rows, cols, cell_width_px, cell_height_px)
     }
 
     pub fn scroll_up(&self, lines: usize) {
@@ -662,7 +668,13 @@ impl GhosttyPaneTerminal {
         }
     }
 
-    pub fn resize(&self, rows: u16, cols: u16, cell_width_px: u32, cell_height_px: u32) {
+    pub fn resize(
+        &self,
+        rows: u16,
+        cols: u16,
+        cell_width_px: u32,
+        cell_height_px: u32,
+    ) -> Vec<Bytes> {
         if let Ok(mut core) = self.core.lock() {
             let offset_from_bottom = core
                 .terminal
@@ -694,6 +706,7 @@ impl GhosttyPaneTerminal {
             let _ = core
                 .terminal
                 .resize(cols, rows, cell_width_px, cell_height_px);
+            let terminal_responses = self.drain_pending_pty_responses();
 
             let bottom_is_blank = ghostty_detection_text(&core)
                 .map(|text| text.trim().is_empty())
@@ -716,6 +729,9 @@ impl GhosttyPaneTerminal {
                     remaining -= 1;
                 }
             }
+            terminal_responses
+        } else {
+            Vec::new()
         }
     }
 
@@ -2622,6 +2638,21 @@ mod tests {
     }
 
     #[test]
+    fn resize_returns_in_band_size_report_response() {
+        let (tx, _rx) = mpsc::channel(4);
+        let mut terminal = crate::ghostty::Terminal::new(80, 24, 0).unwrap();
+        terminal.mode_set(2048, true).unwrap();
+        let pane = GhosttyPaneTerminal::new(terminal, tx).unwrap();
+
+        let responses = pane.resize(40, 100, 9, 18);
+
+        assert_eq!(
+            responses,
+            vec![Bytes::from_static(b"\x1B[48;40;100;720;900t")]
+        );
+    }
+
+    #[test]
     fn synchronized_output_suppresses_intermediate_render_requests_until_batch_ends() {
         let (tx, _rx) = mpsc::channel(4);
         let terminal = crate::ghostty::Terminal::new(80, 24, 0).unwrap();
diff --git a/src/pty/actor.rs b/src/pty/actor.rs
index cce58a75..70634475 100644
--- a/src/pty/actor.rs
+++ b/src/pty/actor.rs
@@ -50,9 +50,15 @@ struct PtyResize {
     cell_height_px: u32,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct PtyResizeRequest {
+    resize: PtyResize,
+    terminal_responses: Vec<Bytes>,
+}
+
 #[derive(Default)]
 struct SharedPtyControls {
-    resize: Option<PtyResize>,
+    resize: Option<PtyResizeRequest>,
     nudge: Option<PtyResize>,
 }
 
@@ -151,17 +157,27 @@ impl PtyIoActorHandle {
         }
     }
 
-    pub(crate) fn resize(&self, rows: u16, cols: u16, cell_width_px: u32, cell_height_px: u32) {
+    pub(crate) fn resize(
+        &self,
+        rows: u16,
+        cols: u16,
+        cell_width_px: u32,
+        cell_height_px: u32,
+        terminal_responses: Vec<Bytes>,
+    ) {
         {
             let mut controls = self
                 .controls
                 .lock()
                 .unwrap_or_else(|poisoned| poisoned.into_inner());
-            controls.resize = Some(PtyResize {
-                rows,
-                cols,
-                cell_width_px,
-                cell_height_px,
+            controls.resize = Some(PtyResizeRequest {
+                resize: PtyResize {
+                    rows,
+                    cols,
+                    cell_width_px,
+                    cell_height_px,
+                },
+                terminal_responses,
             });
         }
         self.wake_actor();
@@ -592,8 +608,9 @@ impl PtyIoActorRunner {
         if self.state == ActorState::Released {
             return;
         }
-        if let Some(resize) = resize {
-            self.resize(resize);
+        if let Some(request) = resize {
+            self.resize(request.resize);
+            self.enqueue_terminal_responses(request.terminal_responses);
         }
         if let Some(nudge) = nudge {
             self.nudge(nudge);
@@ -612,16 +629,19 @@ impl PtyIoActorRunner {
             }
             Ok(n) => {
                 let result = (self.on_read)(&buf[..n]);
-                for response in result.terminal_responses {
-                    if self.state != ActorState::Released {
-                        self.pending_writes.push_back(response);
-                    }
-                }
+                self.enqueue_terminal_responses(result.terminal_responses);
                 true
             }
         }
     }
 
+    fn enqueue_terminal_responses(&mut self, terminal_responses: Vec<Bytes>) {
+        if self.state == ActorState::Released {
+            return;
+        }
+        self.pending_writes.extend(terminal_responses);
+    }
+
     fn flush_pending_writes_once(&mut self) {
         while let Some(bytes) = self.pending_writes.front() {
             let chunk = &bytes[self.current_write_offset..];
@@ -922,18 +942,21 @@ mod tests {
             controls: Arc::clone(&controls),
         };
 
-        handle.resize(20, 80, 8, 16);
-        handle.resize(40, 120, 9, 18);
+        handle.resize(20, 80, 8, 16, vec![Bytes::from_static(b"old")]);
+        handle.resize(40, 120, 9, 18, vec![Bytes::from_static(b"new")]);
         handle.nudge_child_redraw_after_handoff(41, 121, 10, 20);
 
         let controls = controls.lock().expect("controls lock");
         assert_eq!(
             controls.resize,
-            Some(PtyResize {
-                rows: 40,
-                cols: 120,
-                cell_width_px: 9,
-                cell_height_px: 18,
+            Some(PtyResizeRequest {
+                resize: PtyResize {
+                    rows: 40,
+                    cols: 120,
+                    cell_width_px: 9,
+                    cell_height_px: 18,
+                },
+                terminal_responses: vec![Bytes::from_static(b"new")],
             })
         );
         assert_eq!(
@@ -947,6 +970,20 @@ mod tests {
         );
     }
 
+    #[test]
+    fn resize_writes_terminal_responses_after_applying_resize() {
+        let (handle, mut peer, _read_rx) = actor_with_socket_pair(false);
+        let response = Bytes::from_static(b"\x1B[48;40;100;720;900t");
+
+        handle.resize(40, 100, 9, 18, vec![response.clone()]);
+
+        let mut buf = vec![0; response.len()];
+        peer.read_exact(&mut buf)
+            .expect("peer receives resize response");
+        assert_eq!(Bytes::from(buf), response);
+        handle.shutdown();
+    }
+
     #[tokio::test]
     async fn async_user_input_waits_for_queue_capacity() {
         let (data_tx, mut data_rx) = mpsc::channel(1);