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]>

2 files changed, 14 insertions, 0 deletions

diff --git a/src/ninep/pty.zig b/src/ninep/pty.zig
index eda6e9d0..f788b4f8 100644
--- a/src/ninep/pty.zig
+++ b/src/ninep/pty.zig
@@ -806,6 +806,18 @@ test "a run's answer says cut when its output's start is gone, and reads a bound
     try testing.expectEqualStrings("error out of memory\n", sh.answered(p, node, h, into));
 }
 
+test "closing a terminal pane asks its shell to hang up the pty" {
+    const p = try withTerm(testing.allocator);
+    defer p.deinit();
+    _ = try th.newPane(p);
+    const closed = th.rmdir(p, Node.of(serialOf(p), .dir));
+    try testing.expectEqual(Status.ok, closed.reply.status);
+    try testing.expect(closed.closed);
+    // A text pane has no shell to end.
+    const text = try th.newPane(p);
+    try testing.expect(!th.rmdir(p, Node.of(text, .dir)).closed);
+}
+
 test "the pty queue drops the oldest at its cap" {
     const gpa = testing.allocator;
     const p = try withTerm(gpa);
diff --git a/src/ninep/testing.zig b/src/ninep/testing.zig
index 6ea40956..fce77f10 100644
--- a/src/ninep/testing.zig
+++ b/src/ninep/testing.zig
@@ -19,6 +19,7 @@ pub const Answer = struct {
     winsize: ?struct { cols: u16, rows: u16 } = null,
     signal: ?pardes.PtySignal = null,
     spawned: bool = false,
+    closed: bool = false,
 
     pub fn pty(a: *const Answer) []const u8 {
         return a.pty_buf[0..a.pty_len];
@@ -44,6 +45,7 @@ pub fn call(p: *Pardes, req: Req) Answer {
         },
         .resize_pty => |r| ans.winsize = .{ .cols = r.cols, .rows = r.rows },
         .signal_pty => |s| ans.signal = s.sig,
+        .close_pty => ans.closed = true,
         .spawn => ans.spawned = true,
         else => {},
     };