A terminal pane that closes takes its shell and pty with it, in every front end

The detached server closed a pane's pty only when the shell was respawned,
hit EOF or the session shut down, so rmdir, Del or Delcol on a terminal
left its shell running with nobody to read it; the tty front end and
macOS did the same. Retiring a terminal pane now emits a close_pty
effect, which each host that runs shells answers by hanging the pty up
and ending the shell (the detached server's and the GUI's existing
retire-and-reap path, and a close plus SIGHUP in the tty and macOS
shells).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index fbc3e119..442a3a30 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -3095,6 +3095,9 @@ pub const Effect = union(enum) {
     write: struct { pane: u8, bytes: Buf(64) },
     resize_pty: struct { pane: u8, cols: u16, rows: u16 },
     signal_pty: struct { pane: u8, sig: PtySignal },
+    /// The terminal pane in this slot is gone: the shell hangs up its pty
+    /// and ends the shell, rather than leave it running with nobody to read.
+    close_pty: struct { pane: u8 },
     open_link: Buf(256),
     /// write this pane's file content to its path; the shell reads both off
     /// the core (content is unbounded, effects are fixed-size values)
@@ -4129,6 +4132,7 @@ pub const Pardes = struct {
         const watched = (if (pane.file) |f| f.output == null else false) or pane.hasPdf();
         for (p.panes, 0..) |slot, id| if (slot == pane) {
             if (watched) p.emit(.{ .watch = .{ .pane = @intCast(id), .on = false } });
+            if (pane.isTerminal()) p.emit(.{ .close_pty = .{ .pane = @intCast(id) } });
             ctlfs.events.noteRetire(p, pane);
             // ...and so do bytes still queued for the pty it no longer has.
             p.dropPendingWrite(id);
@@ -4522,6 +4526,7 @@ pub const Pardes = struct {
             .write => |w| if (v.pty_write) |f| f(p.host.ctx, w.pane, w.bytes.slice()),
             .resize_pty => |r| if (v.pty_resize) |f| f(p.host.ctx, r.pane, r.cols, r.rows),
             .signal_pty => |s| if (v.pty_signal) |f| f(p.host.ctx, s.pane, s.sig),
+            .close_pty => |c| if (v.close_pty) |f| f(p.host.ctx, c.pane),
             .open_link => |u| if (v.open_link) |f|
                 f(p.host.ctx, u.slice())
             else