A command from a missing directory fails ENOENT with no pane; one whose shell never started ends exit 127

Exec made a command pane in a directory that was not there, whose shell
never started: it said running for ever, a follower waited for an exit
that never came, and Kill found it. The line now fails up front, as Tty
does, `exec: <dir>: no such directory`; and a command pane whose shell
the host could not start ends `exit 127` at once. A shell that could not
start in its directory says `directory missing`, not `file not found`.

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

1 files changed, 31 insertions, 0 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 66092451..9cf97efc 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -1918,6 +1918,37 @@ test "a terminal with text typed at its prompt is never typed into: a look at it
     try testing.expect(!typed_into);
 }
 
+test "a command line from a missing directory fails ENOENT and makes no pane; a command whose shell never started ends 127" {
+    const p = try withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    const Starting = struct {
+        fn spawn(_: ?*anyopaque, _: u8, _: []const u8) void {}
+    };
+    p.host = .{ .vtable = &.{ .spawn = Starting.spawn } };
+    defer p.host = .{};
+    const serial = serialOf(p);
+    _ = wr(p, Node.of(serial, .name), "/tmp/pardes-no-such-dir-zz/f.txt\n");
+    var count: usize = 0;
+    for (p.panes) |slot| count += @intFromBool(slot != null);
+    const refused = wr(p, Node.of(serial, .exec), "echo hi\n");
+    try testing.expectEqual(E.NOENT, refused.errno());
+    try testing.expectStringStartsWith(refused.reply.ename, "exec: /tmp/pardes-no-such-dir-zz: no such directory");
+    var after: usize = 0;
+    for (p.panes) |slot| after += @intFromBool(slot != null);
+    try testing.expectEqual(count, after);
+    // A command pane whose shell the host could not start.
+    _ = wr(p, Node.of(serial, .name), "/tmp/f.txt\n");
+    try testing.expectEqual(Status.ok, wr(p, Node.of(serial, .exec), "echo hi\n").reply.status);
+    const cmd = p.paneBySerial(try std.fmt.parseInt(u32, std.mem.trimEnd(u8, rd(p, Node.of(serial, .exec), 0, 64).bytes, "\n"), 10)).?;
+    p.shellFailed(@intCast(cmd), error.FileNotFound);
+    const pane = p.panes[cmd].?;
+    try testing.expect(pane.command_done);
+    try testing.expectEqual(@as(?u8, 127), pane.command_status);
+    var rec: [32]u8 = undefined;
+    try testing.expect(th.logHas(p, try std.fmt.bufPrint(&rec, "exit {d} 127\n", .{pane.serial})));
+    try testing.expect(th.logHas(p, "shell: directory missing"));
+}
+
 test "size is monotonic: growing is never refused, and a size once taken is taken again" {
     const p = try Pardes.init(testing.allocator, .{ .tty_only = true, .cols = 160, .rows = 60 });
     defer p.deinit();