Errors are said in words, and a refusal names what it takes

A failure read `Del k|j: InvalidArgument`, `Kill: NoSuchCommand`, `ill-formed control message`, or nothing at all. reportError now spells an error's name as words, and the refusals name their accepted forms: pty/ctl lists its verbs, a flag file takes 1 or 0, a setting word takes on or off, Del takes k, j or nothing, Repl takes - or a language. Kill with nothing to stop says so, /focus says pane, a Look that found nothing says no match, and pty/run on a command pane says it is not a shell. A ctl write's failure has room for the Repl list and is cut between words, the Repl word at a character.

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

1 files changed, 3 insertions, 3 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 4e1c039b..680a09b0 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -200,7 +200,7 @@ const Builtin = builtins.registry.Builtin();
 /// Refuses a control message, quoting it the way Plan 9's cmderror does
 /// (kernel/misc/parse.c:82): `unknown control message "Bogus 3"`.
 fn refuse(p: *Pardes, req: Req, why: []const u8, line: []const u8) Reply {
-    const room = p.fs.ename.len - why.len - 3;
+    const room = p.fs.ename.len -| (why.len + 3);
     const text = std.fmt.bufPrint(&p.fs.ename, "{s} \"{s}\"", .{ why, line[0..@min(line.len, room)] }) catch why;
     return tree.failText(req.tag, E.INVAL, text);
 }
@@ -399,7 +399,7 @@ pub fn writeFocus(p: *Pardes, req: Req) Reply {
     return .{ .tag = req.tag, .written = @intCast(req.data.len) };
 }
 
-const e_no_pane = "no such window";
+const e_no_pane = "no such pane";
 
 pub fn readPane(p: *Pardes, req: Req, pane: *Pane) Reply {
     var buf: [pane_text_cap]u8 = undefined;
@@ -666,7 +666,7 @@ test "the root ctl reads the settings as a write takes them, and takes the sessi
     // its line; the lines before it have taken effect, as in acme.
     const failed = wr(p, root_ctl, "Verbose on\nMount x\nVerbose off");
     try testing.expectEqual(E.IO, failed.errno());
-    try testing.expectEqualStrings("Mount name dial: MissingArgument \"Mount x\"", failed.reply.ename);
+    try testing.expectEqualStrings("Mount name dial: missing argument \"Mount x\"", failed.reply.ename);
     try testing.expect(p.settings.verbose);
     try testing.expect(!p.fs.no_prompt);
     try testing.expectEqual(Status.ok, wr(p, root_ctl, "Verbose off").reply.status);