Allow interchain accounts to connect with middleware

[crodriguezvega]

Currently, the OnChanOpenInit callback stack is started by a module calling RegisterInterchainAccount. RegisterInterchainAccount will construct a valid ics27 version. It does not take in any information about potential middleware versions above the ics27 version

[crodriguezvega]

Trying to write down what's needed for this issue to start the discussion...

As discussed in the call today, we need to change the signature of the controller's RegisterInterchainAccount function to something like:

RegisterInterchainAccount(ctx sdk.Context, connectionID, owner, version string) error

Questions:

• Should the version string be a JSON-encoded string that un-marshalls to 29-fee's Metadata type?
• Should we do any kind of validation for the version parameter in RegisterInterchainAccount or just pass it through as it is down to channeltypes.NewMsgChannelOpenInit? Like do we need the AppVersion field to be populated at all with some value (maybe ics27-1?), or can it be just an empty string?
• Will the current JSON-encoded metadata that we marshall as the version string be used to populate the AppVersion field of 29-fee's Metadata type?

[colin-axner]

Should the version string be a JSON-encoded string that un-marshalls to 29-fee's Metadata type?

The version is the full channel version. We cannot assume what the underlying structure is at this entrypoint. The version should simply be passed to the MsgChanOpenInit

Should we do any kind of validation for the version parameter in RegisterInterchainAccount or just pass it through as it is down to channeltypes.NewMsgChannelOpenInit? Like do we need the AppVersion field to be populated at all with some value (maybe ics27-1?), or can it be just an empty string?

No, we cannot since we cannot unwrap the version yet. Checks will happen within OnChanOpenInit

Will the current JSON-encoded metadata that we marshall as the version string be used to populate the AppVersion field of 29-fee's Metadata type?

yes assuming the middleware stacking is ics29 -> ics27 (but there could be many middlewares in between the two)

[crodriguezvega]

Ok, thanks.

So then we need to remove this block of code and pass the version argument directly in here. Correct?

Are there any other changes needed?

[colin-axner]

I think that should work! A test of course should be added to check that this assumption holds