It appears that there is a problem with the Ruby library of show-stopper proportions.
When I first started using the Ruby library a few weeks ago, it did not support custom fields at all. In response to a post that I placed here, Jeremy very kindly (and promptly I might add) modified the library to provide custom-field support for the Subscriber.AddWithCustomFields method. I was delighted. I believed that this fix solved all of my problems because I could not see where I needed custom-field support in any other method. Since then, through my own experience and posts in this forum, I have learned about the returning-subscriber issue. To make a long story short, it seems that in order to force the addition of a returning subscriber one needs to use either the Subscriber.AddAndResubscribe method or the Subscriber.AddAndResubscribeWithCustomFields method. It appears that the Ruby library does not support either of these methods; and, as a result, I am in deep trouble. Jeremy, are you listening? I hope that you are. Any chance of getting a fix for this problem? I'm afraid that it could well be a show stopper for me. Thanks.
Mea maxima culpa. I went into the source code for the Ruby library with the thought of looking into what I would need to do to fix this problem and lo and behold, I find that Jeremy had already fixed it with the prior change. It just wasn't listed as being available. Jeremy, you rock!!! I'm once again a happy camper! :) Thanks.