ipfs/kubo · error

cannot have negative byte count

Error message

cannot have negative byte count

What it means

Guard in the `ipfs files write` handler after truncation handling: a --count option parsed to a negative int64 is rejected before seeking and writing. Validation of the byte-count option, not an I/O failure.

Source

Thrown at core/commands/files.go:1152

				if _, err := mfs.FlushPath(req.Context, nd.FilesRoot, parent); err != nil {
					if retErr == nil {
						retErr = err
					} else {
						flog.Error("files: flushing the parent folder", err)
					}
				}
			}
		}()

		if trunc {
			if err := wfd.Truncate(0); err != nil {
				return err
			}
		}

		count, countfound := req.Options[filesCountOptionName].(int64)
		if countfound && count < 0 {
			return fmt.Errorf("cannot have negative byte count")
		}

		_, err = wfd.Seek(int64(offset), io.SeekStart)
		if err != nil {
			flog.Error("seekfail: ", err)
			return err
		}

		var r io.Reader
		r, err = cmdenv.GetFileArg(req.Files.Entries())
		if err != nil {
			return err
		}
		if countfound {
			r = io.LimitReader(r, int64(count))
		}

		_, err = io.Copy(wfd, r)

View on GitHub (pinned to 329838acdf)

Solutions

1. Pass a non-negative --count, or omit it to write until the input ends.
2. Fix the script or wrapper that derives the count value so it cannot be negative.

When it happens

Trigger: Thrown at core/commands/files.go:1152 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ipfs/kubo@329838acdf (2026-09-03). Data as JSON: /api/errors/81484ca4e381e2b7. Report an issue: GitHub.