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02-client-refactor: rename update to UpdateState for 07-tendermint (c…
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…osmos#1117)

* rename update to UpdateState

rename 07-tendermint update function to UpdateState
add pruneOldestConsensusState function
add check for duplicate update

* fix: duplicate update check was performing incorrect logic

* update godoc

* add UpdateState tests

* update godoc

* chore: fix code spacing

Co-authored-by: Sean King <seantking@users.noreply.github.com>
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@colin-axner @seantking @seunlanlege
2 people authored and seunlanlege committed Aug 9, 2022
1 parent ab8e294 commit 9e7a317
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Showing 2 changed files with 210 additions and 45 deletions.
112 changes: 67 additions & 45 deletions modules/light-clients/07-tendermint/types/update.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,14 +28,6 @@ import (
// - header timestamp is past the trusting period in relation to the consensus state
// - header timestamp is less than or equal to the consensus state timestamp
//
// UpdateClient may be used to either create a consensus state for:
// - a future height greater than the latest client state height
// - a past height that was skipped during bisection
// If we are updating to a past height, a consensus state is created for that height to be persisted in client store
// If we are updating to a future height, the consensus state is created and the client state is updated to reflect
// the new latest height
// UpdateClient must only be used to update within a single revision, thus header revision number and trusted height's revision
// number must be the same. To update to a new revision, use a separate upgrade path
// Tendermint client validity checking uses the bisection algorithm described
// in the [Tendermint spec](https://github.com/tendermint/spec/blob/master/spec/consensus/light-client.md).
//
Expand All @@ -45,10 +37,6 @@ import (
// 2. Any valid update that breaks time monotonicity with respect to its neighboring consensus states is evidence of misbehaviour and will freeze client.
// Misbehaviour sets frozen height to {0, 1} since it is only used as a boolean value (zero or non-zero).
//
// Pruning:
// UpdateClient will additionally retrieve the earliest consensus state for this clientID and check if it is expired. If it is,
// that consensus state will be pruned from store along with all associated metadata. This will prevent the client store from
// becoming bloated with expired consensus states that can no longer be used for updates and packet verification.
func (cs ClientState) CheckHeaderAndUpdateState(
ctx sdk.Context, cdc codec.BinaryCodec, clientStore sdk.KVStore,
header exported.ClientMessage,
Expand Down Expand Up @@ -110,35 +98,10 @@ func (cs ClientState) CheckHeaderAndUpdateState(
return &cs, consState, nil
}

// Check the earliest consensus state to see if it is expired, if so then set the prune height
// so that we can delete consensus state and all associated metadata.
var (
pruneHeight exported.Height
pruneError error
)
pruneCb := func(height exported.Height) bool {
consState, err := GetConsensusState(clientStore, cdc, height)
// this error should never occur
if err != nil {
pruneError = err
return true
}
if cs.IsExpired(consState.Timestamp, ctx.BlockTime()) {
pruneHeight = height
}
return true
}
IterateConsensusStateAscending(clientStore, pruneCb)
if pruneError != nil {
return nil, nil, pruneError
}
// if pruneHeight is set, delete consensus state and metadata
if pruneHeight != nil {
deleteConsensusState(clientStore, pruneHeight)
deleteConsensusMetadata(clientStore, pruneHeight)
newClientState, consensusState, err := cs.UpdateState(ctx, cdc, clientStore, tmHeader)
if err != nil {
return nil, nil, err
}

newClientState, consensusState := update(ctx, clientStore, &cs, tmHeader)
return newClientState, consensusState, nil
}

Expand Down Expand Up @@ -244,11 +207,32 @@ func checkValidity(
return nil
}

// update the consensus state from a new header and set processed time metadata
func update(ctx sdk.Context, clientStore sdk.KVStore, clientState *ClientState, header *Header) (*ClientState, *ConsensusState) {
// UpdateState may be used to either create a consensus state for:
// - a future height greater than the latest client state height
// - a past height that was skipped during bisection
// If we are updating to a past height, a consensus state is created for that height to be persisted in client store
// If we are updating to a future height, the consensus state is created and the client state is updated to reflect
// the new latest height
// UpdateState must only be used to update within a single revision, thus header revision number and trusted height's revision
// number must be the same. To update to a new revision, use a separate upgrade path
// UpdateState will prune the oldest consensus state if it is expired.
func (cs ClientState) UpdateState(ctx sdk.Context, cdc codec.BinaryCodec, clientStore sdk.KVStore, clientMsg exported.ClientMessage) (*ClientState, *ConsensusState, error) {
header, ok := clientMsg.(*Header)
if !ok {
return nil, nil, sdkerrors.Wrapf(clienttypes.ErrInvalidClientType, "expected type %T, got %T", &Header{}, header)
}

// check for duplicate update
if consensusState, _ := GetConsensusState(clientStore, cdc, header.GetHeight()); consensusState != nil {
// perform no-op
return &cs, consensusState, nil
}

cs.pruneOldestConsensusState(ctx, cdc, clientStore)

height := header.GetHeight().(clienttypes.Height)
if height.GT(clientState.LatestHeight) {
clientState.LatestHeight = height
if height.GT(cs.LatestHeight) {
cs.LatestHeight = height
}
consensusState := &ConsensusState{
Timestamp: header.GetTime(),
Expand All @@ -259,5 +243,43 @@ func update(ctx sdk.Context, clientStore sdk.KVStore, clientState *ClientState,
// set metadata for this consensus state
setConsensusMetadata(ctx, clientStore, header.GetHeight())

return clientState, consensusState
return &cs, consensusState, nil
}

// pruneOldestConsensusState will retrieve the earliest consensus state for this clientID and check if it is expired. If it is,
// that consensus state will be pruned from store along with all associated metadata. This will prevent the client store from
// becoming bloated with expired consensus states that can no longer be used for updates and packet verification.
func (cs ClientState) pruneOldestConsensusState(ctx sdk.Context, cdc codec.BinaryCodec, clientStore sdk.KVStore) {
// Check the earliest consensus state to see if it is expired, if so then set the prune height
// so that we can delete consensus state and all associated metadata.
var (
pruneHeight exported.Height
pruneError error
)

pruneCb := func(height exported.Height) bool {
consState, err := GetConsensusState(clientStore, cdc, height)
// this error should never occur
if err != nil {
pruneError = err
return true
}

if cs.IsExpired(consState.Timestamp, ctx.BlockTime()) {
pruneHeight = height
}

return true
}

IterateConsensusStateAscending(clientStore, pruneCb)
if pruneError != nil {
panic(pruneError)
}

// if pruneHeight is set, delete consensus state and metadata
if pruneHeight != nil {
deleteConsensusState(clientStore, pruneHeight)
deleteConsensusMetadata(clientStore, pruneHeight)
}
}
143 changes: 143 additions & 0 deletions modules/light-clients/07-tendermint/types/update_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -367,6 +367,149 @@ func (suite *TendermintTestSuite) TestCheckHeaderAndUpdateState() {
}
}

func (suite *TendermintTestSuite) TestUpdateState() {
var (
path *ibctesting.Path
clientMessage exported.ClientMessage
pruneHeight clienttypes.Height
updatedClientState *types.ClientState // TODO: retrieve from state after 'UpdateState' call
updatedConsensusState *types.ConsensusState // TODO: retrieve from state after 'UpdateState' call
)

testCases := []struct {
name string
malleate func()
expResult func()
expPass bool
}{
{
"success with height later than latest height", func() {
suite.Require().True(path.EndpointA.GetClientState().GetLatestHeight().LT(clientMessage.GetHeight()))
},
func() {
suite.Require().True(path.EndpointA.GetClientState().GetLatestHeight().LT(updatedClientState.GetLatestHeight())) // new update, updated client state should have changed
}, true,
},
{
"success with height earlier than latest height", func() {
// commit a block so the pre-created ClientMessage
// isn't used to update the client to a newer height
suite.coordinator.CommitBlock(suite.chainB)
err := path.EndpointA.UpdateClient()
suite.Require().NoError(err)

suite.Require().True(path.EndpointA.GetClientState().GetLatestHeight().GT(clientMessage.GetHeight()))
},
func() {
suite.Require().Equal(path.EndpointA.GetClientState(), updatedClientState) // fill in height, no change to client state
}, true,
},
{
"success with duplicate header", func() {
// update client in advance
err := path.EndpointA.UpdateClient()
suite.Require().NoError(err)

// use the same header which just updated the client
clientMessage, err = path.EndpointA.Chain.ConstructUpdateTMClientHeader(path.EndpointA.Counterparty.Chain, path.EndpointA.ClientID)
suite.Require().NoError(err)
suite.Require().Equal(path.EndpointA.GetClientState().GetLatestHeight(), clientMessage.GetHeight())
},
func() {
suite.Require().Equal(path.EndpointA.GetClientState(), updatedClientState)
suite.Require().Equal(path.EndpointA.GetConsensusState(clientMessage.GetHeight()), updatedConsensusState)
}, true,
},
{
"success with pruned consensus state", func() {
// this height will be expired and pruned
err := path.EndpointA.UpdateClient()
suite.Require().NoError(err)
pruneHeight = path.EndpointA.GetClientState().GetLatestHeight().(clienttypes.Height)

// Increment the time by a week
suite.coordinator.IncrementTimeBy(7 * 24 * time.Hour)

// create the consensus state that can be used as trusted height for next update
err = path.EndpointA.UpdateClient()
suite.Require().NoError(err)

// Increment the time by another week, then update the client.
// This will cause the first two consensus states to become expired.
suite.coordinator.IncrementTimeBy(7 * 24 * time.Hour)
err = path.EndpointA.UpdateClient()
suite.Require().NoError(err)

// ensure counterparty state is committed
suite.coordinator.CommitBlock(suite.chainB)
clientMessage, err = path.EndpointA.Chain.ConstructUpdateTMClientHeader(path.EndpointA.Counterparty.Chain, path.EndpointA.ClientID)
suite.Require().NoError(err)
},
func() {
suite.Require().True(path.EndpointA.GetClientState().GetLatestHeight().LT(updatedClientState.GetLatestHeight())) // new update, updated client state should have changed

// ensure consensus state was pruned
_, found := path.EndpointA.Chain.GetConsensusState(path.EndpointA.ClientID, pruneHeight)
suite.Require().False(found)
}, true,
},
{
"invalid ClientMessage type", func() {
clientMessage = &types.Misbehaviour{}
},
func() {}, false,
},
}
for _, tc := range testCases {
tc := tc
suite.Run(tc.name, func() {
suite.SetupTest() // reset
pruneHeight = clienttypes.ZeroHeight()
path = ibctesting.NewPath(suite.chainA, suite.chainB)

err := path.EndpointA.CreateClient()
suite.Require().NoError(err)

// ensure counterparty state is committed
suite.coordinator.CommitBlock(suite.chainB)
clientMessage, err = path.EndpointA.Chain.ConstructUpdateTMClientHeader(path.EndpointA.Counterparty.Chain, path.EndpointA.ClientID)
suite.Require().NoError(err)

tc.malleate()

clientState := path.EndpointA.GetClientState()

// TODO: remove casting when 'UpdateState' is an interface function.
tmClientState, ok := clientState.(*types.ClientState)
suite.Require().True(ok)

clientStore := suite.chainA.App.GetIBCKeeper().ClientKeeper.ClientStore(suite.chainA.GetContext(), path.EndpointA.ClientID)
updatedClientState, updatedConsensusState, err = tmClientState.UpdateState(suite.chainA.GetContext(), suite.chainA.App.AppCodec(), clientStore, clientMessage)

if tc.expPass {
suite.Require().NoError(err)

header := clientMessage.(*types.Header)
expConsensusState := &types.ConsensusState{
Timestamp: header.GetTime(),
Root: commitmenttypes.NewMerkleRoot(header.Header.GetAppHash()),
NextValidatorsHash: header.Header.NextValidatorsHash,
}
suite.Require().Equal(expConsensusState, updatedConsensusState)

} else {
suite.Require().Error(err)
suite.Require().Nil(updatedClientState)
suite.Require().Nil(updatedConsensusState)

}

// perform custom checks
tc.expResult()
})
}
}

func (suite *TendermintTestSuite) TestPruneConsensusState() {
// create path and setup clients
path := ibctesting.NewPath(suite.chainA, suite.chainB)
Expand Down

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