(\*.*Graph).Degree returns 0 for absent node

[kortschak]

(\*.*Graph).Degree returns 0 for absent node

[soniakeys]

Agreed. I would lean toward the multiple return. It's nicer, if a little slower.

[UserAB1236872]

Degree isn't even part of the interface anymore, so we could remove it. If that's not desirable, I'd opt for ok over a panic, because there may be legitimate sane cases where a node's degree is unknown.

[kortschak]

The panic would be for degree of a non-existent node. Surely a node that doesn't exist has no defined degree. If a client is asking about random nodes without checking they exist first I'd rather they be told loudly than be able to d, _ := g.Degree(n). /devils-advocate

[kortschak]

Degree no longer exists on any interface.