From c78641fdbe931ca2e6e87eb3e001bd021c1eba3f Mon Sep 17 00:00:00 2001 From: Gabriel Schneider Date: Tue, 29 Sep 2026 06:16:52 -0300 Subject: A pty/ctl winsize gives a terminal two rows at least, so it no longer reads busy for ever A one-row pty loses the prompt's input mark as soon as the prompt wraps, and busy detection never sees the shell idle again. Placement already keeps a new terminal at tag + 2 rows; a winsize write now keeps the pty at two. A pane dragged down to one body row keeps a one-row pty, since a taller pty than the pane shows would put its cursor below the pane. Co-Authored-By: Claude Opus 5.5 --- docs/fs.md | 5 +++-- src/ninep/pty.zig | 7 ++++++- src/pardes.zig | 5 ++++- test/fs.py | 7 +++++++ 4 files changed, 20 insertions(+), 4 deletions(-) diff --git a/docs/fs.md b/docs/fs.md index 5c2486f4..9ba9c0e4 100644 --- a/docs/fs.md +++ b/docs/fs.md @@ -818,8 +818,9 @@ terminal (a REPL, `less`) takes none: write to `pty/data` for it -- which is also when the third field of `pty/status` reads 1. `pty/status` is one line, three right-aligned fields and a newline: the pty's columns and rows, then busy (0 or 1). The size, and `pty/ctl`'s `winsize` read back, is -what `winsize C R` last set, until the pane itself resizes and gives the pty -its grid again. A line written +what `winsize C R` last set (R of 1 is taken as 2: a one-row pty loses +its prompt's mark and would read busy for ever), until the pane itself +resizes and gives the pty its grid again. A line written before a new terminal's shell has drawn its first prompt is not busy: it waits for that prompt (a respawn meanwhile keeps it waiting for the new shell's) and is sent then, so the first command a script gives a fresh diff --git a/src/ninep/pty.zig b/src/ninep/pty.zig index 046a456a..4009af49 100644 --- a/src/ninep/pty.zig +++ b/src/ninep/pty.zig @@ -28,6 +28,9 @@ fn dimension(word: []const u8) ?u16 { return if (n == 0 or n > winsize_max) null else n; } +/// The fewest rows a winsize write gives a terminal's pty. +pub const pty_rows_min = 2; + /// As the root ctl's `size` (4096 a side). const winsize_max = 4096; const e_winsize_range = std.fmt.comptimePrint("invalid winsize: out of range, 1x1 to {d}x{d}", .{ winsize_max, winsize_max }); @@ -71,7 +74,9 @@ fn verb(p: *Pardes, id: usize, line: []const u8, apply: bool) bool { switch (v) { .winsize => { const cols = dimension(words.next() orelse return false) orelse return false; - const rows = dimension(words.next() orelse return false) orelse return false; + // Two rows at least, as a pane is laid out: a one-row pty + // loses its prompt's input mark and reads busy for ever. + const rows = @max(pty_rows_min, dimension(words.next() orelse return false) orelse return false); if (words.next() != null) return false; if (!apply) return true; p.emit(.{ .resize_pty = .{ .pane = @intCast(id), .cols = cols, .rows = rows } }); diff --git a/src/pardes.zig b/src/pardes.zig index dd9d91c8..6341de91 100644 --- a/src/pardes.zig +++ b/src/pardes.zig @@ -6596,7 +6596,10 @@ pub const Pardes = struct { pane.tag_top = @intCast(@min(top, lines - pane.tag_rows)); } else pane.tag_top = 0; const cols = @max(1, r.w -| config.GUTTER); - const rows = @max(1, r.h -| pane.tag_rows); // the tag steals the top rows + // The tag steals the top rows. The pty is what the pane shows, + // even one row dragged short: a taller pty would put its cursor + // below the pane (only winsize keeps two, ctlfs.pty). + const rows = @max(1, r.h -| pane.tag_rows); // A terminal's pty follows its pane down to a row, whatever the // resize; only a folded one keeps the size it had, and one not // placed yet the grid it was made with. diff --git a/test/fs.py b/test/fs.py index 8d16d718..45fdbc38 100644 --- a/test/fs.py +++ b/test/fs.py @@ -435,6 +435,13 @@ def run_file(binary): assert run(client, term, b'fi\n') == b'error not run\n' # a syntax error runs nothing assert run(client, term, b"echo 'open\n") == b'error not run\n' # nor does an open quote assert run(client, term, b'true\n') == b'exit 0\n' # ...and the shell is clear after + # A pty asked for one row gets two: one loses the prompt's input + # mark, and the shell would read busy for ever. + client.write(f'/pane/{term}/pty/ctl', b'winsize 20 1\n') + time.sleep(.5) + assert run(client, term, b'true\n') == b'exit 0\n' + assert client.read(f'/pane/{term}/pty/ctl').split()[2] == b'2', client.read(f'/pane/{term}/pty/ctl') + client.write(f'/pane/{term}/pty/ctl', b'winsize 80 24\n') with Client(address) as other: slow = [] waiter = threading.Thread(target=lambda: slow.append(run(other, term, b'sleep 1\n')), daemon=True) -- cgit v1.3