Parameter Change Proposal

[mossid]

Add ParameterChangeProposal to params proposal type. type Proposal is already defined as an interface, and TextProposal implements it without doing actual state transition, so we can define additional proposal types by embedding TextProposal.

type ParameterChange struct {
    Key string
    Subkey string
    Value interface{}
}

type ParameterChangeProposal struct {
    TextProposal
    Changes []ParameterChange
}

To apply the proposal to the state, we can add type ProposalHandler. Modules who wants to add new proposal type can define func NewProposalHandler(k Keeper) ProposalHandler, which can be registered to gov.Keeper. When a new proposal has been passed, the keeper will pass the proposal into the handler, where then the other keepers modify the state.

// package gov
type ProposalHandler func(sdk.Context, Proposal) error

// see baseapp/router.go
type ProposalRouter interface {
    AddRouter(r string, h ProposalHandler) ProposalRouter
    Route(path string) ProposalHandler
}

func (k Keeper) ProposalRouter() Router {
    return k.router
}

// package params
func NewProposalHandler(k Keeper) sdk.ProposalHandler {
    return func(ctx sdk.Context, prop sdk.Proposal) error {
        switch prop := prop.(type) {
        case ParameterChangeProposal:
            // ...
        }
    }
}

type Proposal will moved into types so the modules who want to define new Proposal type can just import types not gov.

[hleb-albau]

Hi,
A very desirable feature. Also, enabling tokens transfers can be done via such government mechanism. Is it in progress? Will we see it on the mainnet? Can we help implement that feature?

[alexanderbez]

@mossid is there any progress on this?

[cwgoes]

Example possible parameter change proposals:

• Increasing number of max validators
• Changing the inflation rate
• Changing consensus parameters (max block size, gas limits)
• Changing slashing parameters (amounts, liveness windows)
• Changing reward distribution fractions (to proposer, bonus for precommits, etc)
• Changing governance parameters (quorum)
• Changing unbonding period
• Enabling/disabling message types