v015-MIGRATION.md

Breaking changes in the large refactor of go-multiaddr v0.15

• There is no Multiaddr interface type.
• Multiaddr is now a concrete type. Not an interface.
• Empty Multiaddrs/Component should generally be checked with .Empty(), not == nil. This is similar to how slices should be checked with len(s) == 0 rather than s == nil.
• Components do not implement Multiaddr as there is no Multiaddr to implement.
• Multiaddr can no longer be a key in a Map. If you want unique Multiaddrs, use Multiaddr.String() as the key, otherwise you can use the pointer value *Multiaddr.

Callouts

• Multiaddr.Bytes() is a O(n) operation for n Components, as opposed to a O(1) operation.

Migration tips for v0.15

• If appending a *Component to a Multiaddr, prefer the Multiaddr.AppendComponent method as it will perform a nil pointer check on the *Component before appending. If you know a *Component is not nil, you may use append normally.
• the Multiaddr type is simply a []Component.
  • You can use append when you have a Component.
  • You can use for range loops.
• If your use case supports it, prefer append or AppendComponent to append a Component to a Multiaddr rather than using Encapsulate or Join. It's much faster as it does not do a defensive copy.
  • Likewise, to join two Multiaddrs, append will perform better than Encapsulate or Join.