Arvados

checkin() in vwd.py has this code (rewrapped a bit for readability):

collections[pdh] = arvados.collection.CollectionReader(
    pdh,
    api_client=outputcollection._my_api(),
    keep_client=outputcollection._my_keep(),
    num_retries=5)

It shouldn't sneak into outputcollection's private methods this way. The whole reason we follow the leading underscore convention is that we don't want to make API compatibility promises to Crunch scripts about them. We undermine ourselves if we ignore that guidance in our own Crunch scripts.

There's no reason this code shouldn't instantiate its own API and Keep clients, and pass them to both outputcollection and all these CollectionReaders.