Should it be possible to add a collection to itself? Twice?

[gwillen]

I notice that:

• I can add a collection to itself
• I can add the same capability to a collection multiple times.

Should one or both of these be prohibited?

Prohibiting the former would probably be mostly cosmetic, assuming one doesn't also prohibit more general cycles in the containment graph (which might be a good idea but might also be annoying to detect.)

Prohibiting the latter also seems mostly cosmetic but it's hard for me to imagine a non-accidental reason to do it.

[jadeqwang]

@kentonv I noticed the guy sitting next to me during the demo yesterday was adding a collection to itself a bunch of times because he had an empty account and he had no other grains to add. It may or may not have been a little confusing when there isn't already a population of grains in the user's workspace.

[kentonv]

@jadeqwang That particular confusion would also be solved by the powerbox offering a way to create a new grain rather than choosing an existing one.

@gwillen Yeah, both of those should maybe be detected, although the question of how to detect that two capabilities are the same is actually rather theoretically complicated...