A ctl line that ran and failed is not quoted after its reason; only one refused before running is

Failures of a builtin through a ctl quoted the line after the builtin's
own words, which already named it (`Mount dead /x: dial failed: no answer
"Mount dead /x"`), while the same failure through exec did not. A line
that ran says why in its own words everywhere now; only a line refused
as no message at all quotes it, as Plan 9's cmderror does.

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

2 files changed, 17 insertions, 13 deletions

diff --git a/docs/fs.md b/docs/fs.md
index 72789182..8f50a45b 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -270,8 +270,10 @@ all of them, `ThemeSel`'s list, are too many for an error);
 and `not a session control message "X": write it to pane/<n>/ctl` or `not
 a window control message "X": write it to /ctl` for a word of the other ctl. 9ns maps them all to EINVAL, and a write
 refused here has done nothing. A line that then fails as it runs fails the
-write with the error the editor reports for it and the line, e.g. `Mount:
-already mounted "Mount peer /tmp/s"` (EIO), and `control message needs its
+write with the error the editor reports for it, in its own words, which
+name what failed, the line not quoted after them (only a line refused
+before it runs, as no message at all, is quoted), e.g. `Mount: already
+mounted` (EIO), and `control message needs its
 argument "Save"` (EINVAL), for a builtin that would have asked at a prompt
 (a `Save` on a scratch) rather than open one nobody is there to answer. A
 builtin that means nothing without its argument (`Mount`, `Msg`, `Find`),
diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 2b256b1e..cf2068bc 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -447,11 +447,13 @@ pub fn runBuiltin(p: *Pardes, req: Req, id: usize, line: []const u8) ?Reply {
     if (!created) noteResult(p, context);
     if (p.fs.refused) return refuse(p, req, e_prompt, line);
     if (p.fs.failure_len == 0) return null;
-    // An Edit's failure names what failed (the pattern that missed): its
-    // line, a program, is not quoted after it.
-    const edit = std.mem.startsWith(u8, line, "Edit ") or std.mem.eql(u8, line, "Edit");
-    const refusal = if (edit) tree.failText(req.tag, E.IO, p.fs.failure[0..p.fs.failure_len]) else refuse(p, req, p.fs.failure[0..p.fs.failure_len], line);
-    return .{ .tag = req.tag, .status = .err, .errno = failureErrno(p.fs.failure[0..p.fs.failure_len]), .ename = refusal.ename };
+    // A line that ran and failed says why in the builtin's own words, which
+    // name what failed (`Mount peer /tmp/s: dial failed: ...`): the line is
+    // not quoted after them, as an exec's is not. Only a line refused before
+    // it runs, as no message at all, quotes it (`unknown control message
+    // "X"`).
+    const failure = p.fs.failure[0..p.fs.failure_len];
+    return tree.failText(req.tag, failureErrno(failure), std.fmt.bufPrint(&p.fs.ename, "{s}", .{failure}) catch failure);
 }
 
 const e_prompt = "control message needs its argument";
@@ -774,8 +776,8 @@ pub fn writePane(p: *Pardes, req: Req, pane: *Pane) Reply {
                     var said_buf: [320]u8 = undefined;
                     const said = said_buf[0..said_in_ename.len];
                     @memcpy(said, said_in_ename);
-                    const r = refuse(p, req, said, line);
-                    return .{ .tag = req.tag, .status = .err, .errno = E.IO, .ename = r.ename };
+                    // It ran and was refused: its words, not the line quoted.
+                    return tree.failText(req.tag, E.IO, std.fmt.bufPrint(&p.fs.ename, "{s}", .{said}) catch said);
                 }
                 var failed: anyerror = error.Unexpected;
                 const errno = get(p, pane, &failed);
@@ -1095,7 +1097,7 @@ 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: missing argument \"Mount x\"", failed.reply.ename);
+    try testing.expectEqualStrings("Mount name dial: missing argument", 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);
@@ -1453,7 +1455,7 @@ test "get reloads the pane from disk and reports a missing file without losing d
     // Unsaved text is asked about once, as acme's get asks winclean.
     const asked = wr(p, ctl_node, "get\n");
     try testing.expectEqual(E.IO, asked.errno());
-    try testing.expect(std.mem.endsWith(u8, asked.reply.ename, ": Modified (get again to discard) \"get\""));
+    try testing.expect(std.mem.endsWith(u8, asked.reply.ename, ": Modified (get again to discard)"));
     try testing.expectEqual(E.NOENT, wr(p, ctl_node, "get\n").errno());
     try testing.expect(p.paneBySerial(serial) != null);
     try testing.expectEqualStrings("from disk\nunsaved\n", pane.file.?.content);
@@ -1701,7 +1703,7 @@ test "a builtin that fails a ctl write logs only its err, so the same failure ag
     const log = @intFromEnum(tree.TopFile.log);
     const h = call(p, .{ .tag = 1, .op = .open, .node = log }).reply.handle;
     const text = call(p, .{ .tag = 2, .op = .read, .node = log, .handle = h, .size = 1 << 16 }).bytes;
-    try testing.expect(std.mem.endsWith(u8, text, "err - ctl: Kill: no running command has that first word \"Kill zzz\" (x3)\n"));
+    try testing.expect(std.mem.endsWith(u8, text, "err - ctl: Kill: no running command has that first word (x3)\n"));
     try testing.expect(std.mem.indexOf(u8, text, "msg - Kill") == null);
     _ = call(p, .{ .tag = 3, .op = .release, .node = log, .handle = h });
 }
@@ -1760,7 +1762,7 @@ test "Mount dials its peer and fails, mounting nothing, when none answers; a loo
     const dead = "/tmp/pardes-test-no-such-peer.sock";
     const refused = wr(p, root_ctl, "Mount dead " ++ dead ++ "\n");
     try testing.expectEqual(E.IO, refused.errno());
-    try testing.expectEqualStrings("Mount dead " ++ dead ++ ": dial failed: no answer \"Mount dead " ++ dead ++ "\"", refused.reply.ename);
+    try testing.expectEqualStrings("Mount dead " ++ dead ++ ": dial failed: no answer", refused.reply.ename);
     try testing.expectEqual(@as(usize, 0), p.fs.mounts.items.len);
     // A pane of a peer gone since: get says so too.
     try p.fs.mounts.append(p.gpa, .{ .name = try p.gpa.dupe(u8, "away"), .dial = try p.gpa.dupe(u8, dead) });