Maybe I'm missing something obvious but I am stuck on populating the URL of a feed node when the feed node is created by another feed.

Here's what I'm actually trying to do:

1. Fetch a list of hotels and create a node for each hotel, using http fetcher and the json parser. This works fine, but I need more detail, and that is available only by fetching hotel-specific bit of JSON. Therefore I configured this node type as a feeds node and created a second feed is invoked when an item is created.

2. Add the detail to each node by fetching JSON from an API server, using the Feeds Self Node Processor.

#1 works with one exception: I can't store the detail JSON URL. I can construct it using Feeds Tamper, and I can put it in a regular text field with no problem, but assigning it to the URL does nothing. The feed node gets created with the URL field blank and everything else populated.

I can make #2 work on manually created nodes, so Feeds Self Node Processor seems to be working fine. I can manually edit each node and copy the feed URL from the text field I created into the URL field for the feed, save the node, and then manually invoke the feed -- but that kind of defeats the purpose of using feed in the first place.

There is probably some good documention on this issue somewhere, but because the terms "feeds node" are so generic, I'm not finding it.