A ctl or exec line with no newline runs with its write and fails it, unless it needs more

A last line with no newline was held to the close, so printf bogus > ctl answered 0 and failed only in the log, Edit ,s/zzz/y/ too. A write shorter than its Twrite is the whole of what was written (acme takes each write whole): its tail runs then and a failure is the write's. It is held only when the parser says it needs more -- an open { block, an a/c/i text -- or when the write filled its Twrite and may go on (the listener tells the core the room, msize less its header).

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

1 files changed, 4 insertions, 0 deletions

diff --git a/src/fs.zig b/src/fs.zig
index 753a4446..845e6424 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -1326,6 +1326,10 @@ pub const Namespace = struct {
     /// A 9P write asked a language server something: the answer count it
     /// waits to change (`turn.lsp_answers`), so its failure is the write's.
     lsp_answer_at: ?u64 = null,
+    /// The most a Twrite of the request being served can carry (msize less
+    /// its header), 0 when unknown: a write shorter than it is the whole of
+    /// what its client wrote, one that fills it may be cut and go on.
+    write_room: u32 = 0,
     /// The serial of the pane the root's exec or look last ran a line at
     /// (the keyboard's), 0 before one: its err record names that pane.
     ran_at: u32 = 0,