An Edit filter that can never be reaped no longer holds the Edit's answer: at the limit the command's group is killed and reaped off the answer's path, the stdin writer owning its input, so a filter writing its own ctl with > or >> answers EIO at 10 s instead of hanging; a running Edit keeps its own copies of the names it reports, and the panes it changes refuse Del, delete, rmdir, Undo, Redo, Get and Zerox (busy, EBUSY); e and r say unreadable files in Get's words; the reference says both sides of a filter's own ctl write need <>

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

1 files changed, 2 insertions, 0 deletions

diff --git a/src/ninep/tree.zig b/src/ninep/tree.zig
index c78a1aa2..8d3c599f 100644
--- a/src/ninep/tree.zig
+++ b/src/ninep/tree.zig
@@ -937,6 +937,8 @@ fn remove(p: *Pardes, req: Req) Reply {
     };
     if (t.file != .dir) return Reply.fail(req.tag, E.PERM);
     const id = p.paneBySerial(t.serial) orelse return Reply.fail(req.tag, E.NOENT);
+    // A pane an Edit's running commands will change stays until they end.
+    if (@import("../edit_cmd.zig").busyOn(p, id)) return failText(req.tag, E.BUSY, @import("../edit_cmd.zig").e_busy);
     p.removePane(id, null) catch return Reply.fail(req.tag, E.IO);
     return .{ .tag = req.tag };
 }