A 9P error past 128 bytes keeps its reason: the path in it gives up its middle to …

An Rerror carries 128 bytes (Plan 9's ERRMAX) and the engine cut longer text there, and a builtin's failure was first clipped between words to 256 with ...: either way the end, which says why, was what went. tree.handle now fits a long reason by cutting the middle of its longest path, else of the whole text, on a character boundary, and reportFailure fills its buffer the same way.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/src/ninep/events.zig b/src/ninep/events.zig
index c0bf4a9a..fe7af77e 100644
--- a/src/ninep/events.zig
+++ b/src/ninep/events.zig
@@ -1289,7 +1289,7 @@ test "a record is one line of UTF-8: DEL and C1 are spaces, bytes not UTF-8 are
     try testing.expectEqualStrings("msg - caf\xc3\xa9\n", sanitize("msg - caf\xc3\xa9\n", &out));
 }
 
-test "a long err record is cut between words, with an ellipsis" {
+test "a long err record keeps its end, its middle given up to an ellipsis" {
     const p = try withFile(testing.allocator, "x\n");
     defer p.deinit();
     _ = wr(p, @intFromEnum(tree.TopFile.ctl), "Bogus " ++ "abcdefgh " ** 40 ++ "\n");
@@ -1298,7 +1298,9 @@ test "a long err record is cut between words, with an ellipsis" {
     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"));
+    try testing.expect(std.mem.indexOf(u8, record, "…") != null);
+    try testing.expect(std.mem.startsWith(u8, record, "err - ctl: "));
+    try testing.expect(std.mem.endsWith(u8, record, "abcdefgh\"\n") or std.mem.endsWith(u8, record, "abcdefgh \"\n"));
     _ = call(p, .{ .tag = 3, .op = .release, .node = log, .handle = h });
 }