A long err record is cut between words, with an ellipsis

An err record's reason was cut at 200 bytes, mid-word. It is now cut at
the last word that fits, and ends with an ellipsis.

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

1 files changed, 16 insertions, 1 deletions

diff --git a/src/ninep/events.zig b/src/ninep/events.zig
index 105397f3..dd29b207 100644
--- a/src/ninep/events.zig
+++ b/src/ninep/events.zig
@@ -202,7 +202,9 @@ pub fn noteError(p: *Pardes, req: Req, reply: Reply) void {
         };
     }
     var buf: [256]u8 = undefined;
-    const record = std.fmt.bufPrint(&buf, "err {s} {s}: {s}\n", .{ serial, file, why[0..@min(why.len, 200)] }) catch return;
+    // A long reason is cut between words, with an ellipsis, never mid-word.
+    const kept = pardes.Messages.clip(why, 200);
+    const record = std.fmt.bufPrint(&buf, "err {s} {s}: {s}{s}\n", .{ serial, file, kept, if (kept.len < why.len) "…" else "" }) catch return;
     for (record[0 .. record.len - 1]) |*c| if (c.* < ' ') {
         c.* = ' ';
     };
@@ -1176,3 +1178,16 @@ test "follow new skips what the log held and waits for what comes after" {
     try testing.expect(std.mem.endsWith(u8, call(p, .{ .tag = 4, .op = .read, .node = log, .handle = h, .size = 4096 }).bytes, " after it\n"));
     _ = call(p, .{ .tag = 5, .op = .release, .node = log, .handle = h });
 }
+
+test "a long err record is cut between words, with an ellipsis" {
+    const p = try withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    _ = wr(p, @intFromEnum(tree.TopFile.ctl), "Bogus " ++ "abcdefgh " ** 40 ++ "\n");
+    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;
+    const at = std.mem.lastIndexOf(u8, text, "err - ctl: ").?;
+    const record = text[at .. std.mem.indexOfScalarPos(u8, text, at, '\n').? + 1];
+    try testing.expect(std.mem.endsWith(u8, record, "abcdefgh…\n"));
+    _ = call(p, .{ .tag = 3, .op = .release, .node = log, .handle = h });
+}