> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sat, 30 Sep 2017 22:02:55 +0000
> Cc: emacs-devel@gnu.org

One more comment:

> +static Lisp_Object
> +json_insert (void *data)
> +{
> +  const struct json_buffer_and_size *buffer_and_size = data;
> +  if (buffer_and_size->size > PTRDIFF_MAX)
> +    xsignal1 (Qoverflow_error, build_string ("buffer too large"));
> +  insert (buffer_and_size->buffer, buffer_and_size->size);
> +  return Qnil;

Shouldn't we follow the call to 'insert' with decode_from_gap, or do
it before json_insert_callback returns?  Or do we trust Jansson to
produce 100% valid UTF-8?