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, 10 insertions, 0 deletions

diff --git a/src/macos.zig b/src/macos.zig
index c9c83a2d..a0abc119 100644
--- a/src/macos.zig
+++ b/src/macos.zig
@@ -2310,6 +2310,7 @@ const vtable: pardes.Host.VTable = .{
     .pty_write = ptyWrite,
     .pty_resize = ptyResize,
     .pty_signal = ptySignal,
+    .close_pty = closePty,
     .tty_taken = ttyTaken,
     .write_file = writeFile,
     .write_dump = writeDump,
@@ -2501,6 +2502,15 @@ fn startReader(st: *State, pt: *Pty, id: u8) void {
     };
 }
 
+/// The pane is gone: its shell goes with it.
+fn closePty(ctx: ?*anyopaque, pane: u8) void {
+    const st = hostState(ctx);
+    const pt = st.ptys[pane] orelse return;
+    _ = libc.kill(pt.pid, posix.SIG.HUP);
+    reap(st, pane);
+    st.gens[pane] +%= 1;
+}
+
 fn reap(st: *State, pane: u8) void {
     var pt = st.ptys[pane] orelse return;
     st.ptys[pane] = null;