docker/cli · error

error while Copy (%s): %w

Error message

error while Copy (%s): %w

What it means

Error "error while Copy (%s): %w" thrown in docker/cli.

Source

Thrown at cli/command/system/dial_stdio.go:85

		err = <-conn2stdout
	case err = <-conn2stdout:
		// return immediately without waiting for stdin to be closed.
		// (stdin is never closed when tty)
	}
	return err
}

func copier(to halfWriteCloser, from halfReadCloser, debugDescription string) error {
	defer func() {
		if err := from.CloseRead(); err != nil {
			logrus.Errorf("error while CloseRead (%s): %v", debugDescription, err)
		}
		if err := to.CloseWrite(); err != nil {
			logrus.Errorf("error while CloseWrite (%s): %v", debugDescription, err)
		}
	}()
	if _, err := io.Copy(to, from); err != nil {
		return fmt.Errorf("error while Copy (%s): %w", debugDescription, err)
	}
	return nil
}

type halfReadCloser interface {
	io.Reader
	CloseRead() error
}

type halfWriteCloser interface {
	io.Writer
	CloseWrite() error
}

type halfCloser interface {
	halfReadCloser
	halfWriteCloser
}

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at cli/command/system/dial_stdio.go:85 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/1343fbce53aecbc5.json. Report an issue: GitHub.