From 3eb85d8b5cb77046aea398cd0d22977f0fc52aa0 Mon Sep 17 00:00:00 2001
From: Kyle Carberry <kyle@carberry.com>
Date: Mon, 15 Jun 2026 18:39:00 +0000
Subject: [PATCH] fix: repaint boo ui after a session resets the terminal (RIS)

In `boo ui` the wheel over the viewport pages local scrollback only when
the focused session is on the primary screen and has not asked for mouse
reporting. The daemon strips alternate-screen toggles from passthrough
and tells the client which screen the application is on out of band, via
a `.screen` message sent only when its filter detects a 47/1047/1049
toggle (plus on attach and redraw).

A full reset (RIS, `ESC c`) returns the terminal to the primary screen
without such a toggle, so the filter never reported a switch and the
client's `app_alt` stayed stuck true. The wheel then sent arrow keys
forever instead of scrolling, and only re-attaching (exit and re-enter
`boo ui`, or a C-a l redraw) recovered it.

Repaint whenever the active screen changes, even when the alt-screen
filter saw no toggle, so a fresh repaint and `.screen` reach the client.

Generated by Coder Agents on behalf of @kylecarbs.
---
 src/daemon.zig       | 12 ++++++++++--
 test/integration.zig | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/src/daemon.zig b/src/daemon.zig
index 191d35b..61a5760 100644
--- a/src/daemon.zig
+++ b/src/daemon.zig
@@ -505,6 +505,11 @@ pub const Daemon = struct {
         // repainted from terminal state.
         var out_buf: [32 * 1024 + 32]u8 = undefined;
         var writer = std.Io.Writer.fixed(&out_buf);
+        // The active screen before this chunk. A switch the filter does
+        // not see (a full reset, RIS, returns to the primary screen
+        // without a 47/1047/1049 toggle) still has to repaint so the
+        // client's `.screen` state stays authoritative.
+        const was_alt = win.onAltScreen();
         const result = win.alt_filter.feed(chunk, &writer) catch
             altscreen.Filter.Result{ .switched = true, .discard_start = 0 };
 
@@ -518,9 +523,12 @@ pub const Daemon = struct {
 
         const filtered = writer.buffered();
         if (filtered.len > 0) conn.send(.output, filtered);
-        if (result.switched) {
+        // Repaint when the filter stripped a toggle, or when the active
+        // screen changed by a path the filter cannot see (e.g. RIS), so
+        // a fresh repaint and `.screen` reach the client either way.
+        if (result.switched or win.onAltScreen() != was_alt) {
             self.repaintTo(conn) catch |err| {
-                log.warn("repaint after screen switch failed: {}", .{err});
+                log.warn("repaint after screen change failed: {}", .{err});
             };
         }
     }
diff --git a/test/integration.zig b/test/integration.zig
index 42dda1c..5eee342 100644
--- a/test/integration.zig
+++ b/test/integration.zig
@@ -2514,6 +2514,43 @@ test "ui: wheel sends arrows to alternate-screen applications" {
     alloc.free(peeked);
 }
 
+test "ui: wheel scrolls again after a session resets the terminal" {
+    const alloc = std.testing.allocator;
+    var h = try Harness.init(alloc);
+    defer h.deinit();
+
+    try h.startDetached("rst", &.{"bash"});
+
+    var ui = try PtyClient.spawn(&h, &.{"ui"}, 24, 100);
+    defer ui.deinit();
+    try ui.waitFor("rst");
+
+    // Enter the alternate screen while attached: the daemon strips the
+    // toggle, repaints, and sends `.screen` = alt, so the wheel would
+    // turn into arrow keys for the application.
+    try h.sendLine("rst", "printf '\\033[?1049hINALT'");
+    try ui.waitFor("INALT");
+
+    // A full reset (RIS, ESC c) returns the terminal to the primary
+    // screen without a 47/1047/1049 toggle, so the alt-screen filter
+    // never sees a switch. The daemon must still repaint and send
+    // `.screen` = primary, or the client keeps treating the session as
+    // alternate-screen and the wheel never pages local scrollback.
+    try h.sendLine("rst", "printf '\\033c'");
+    try h.sendLine("rst", "echo POSTRIS");
+    try ui.waitFor("POSTRIS");
+
+    // Fill the view's scrollback on the primary screen.
+    try h.sendLine("rst", "i=1; while [ $i -le 60 ]; do echo SCROLL-$i; i=$((i+1)); done");
+    try ui.waitFor("SCROLL-60");
+
+    // Wheel up pages local scrollback instead of sending arrows; the
+    // hint only renders while the viewport is scrolled off the bottom.
+    ui.clearOutput();
+    for (0..35) |_| try ui.send("\x1b[<64;50;10M");
+    try ui.waitFor(" scrollback");
+}
+
 test "ui: session titles render in the sidebar" {
     const alloc = std.testing.allocator;
     var h = try Harness.init(alloc);