Use a struct type for client identifiers

[colin-axner]

Summary

Use a struct to manage client identifiers.

Create the type:

type ClientID struct {
    Type       string
    Identifier uint64 // or some other name, Nonce, Sequence?
}

Support the following functions:

func (ClientID) String() string
func (ClientID) IsValid() bool
func (ClientID) IsLocalhost() bool
func ParseClientIdentifier(clientID string) ClientID

Problem Definition

It can be difficult to validate the correctness of our identifier creation/validation since we pass around a string and reference non struct functions defined here.

Proposal

Leave implementation as is for now

I've opened this issue for discussion/idea documentation, but as it could be a major API breaking change, I think it's best to leave this issue as food for thought until we are confident we could make the change without any disruption. It may be useful to use the ClientID for a limited section of the codebase, only change internal APIs.

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For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged/assigned

[colin-axner]

Ah, one issue I already see is that the client identifier format cannot be enforced on counterparty chain values, so this type could only be used to reference ClientID's on the executing chain. Counterparty Client ID types would need to remain being a string. Though this could help clarify the difference in expected usage between the two (counterparty client identifiers should be treated as opaque strings)

[colin-axner]

I don't think this issue will ever be picked up, so going to close