abci++: Propagate vote extensions (RFC 017) (#8433)

* Add protos for ExtendedCommit Cherry-pick from e73f0178b72a16ee81f8e856aadf651f2c62ec6e just the changes to the .proto files, since we have deleted the .intermediate files. Signed-off-by: Thane Thomson <connect@thanethomson.com> * make proto-gen Signed-off-by: Thane Thomson <connect@thanethomson.com> * BlockStore holds extended commit Cherry-pick 8d504d4b50ec6afbdffe2df7ababbef30e15053d and fix conflicts. Signed-off-by: Thane Thomson <connect@thanethomson.com> * Reshuffle ExtendedCommit and ExtendedCommitSig Separate the data structures and functions from their Commit-oriented counterparts to adhere to the current coding style. Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix exit condition in blocksync * Add note to remove TxResult proto As Sergio pointed out in 3e31aa6f583cdc71e208ed03a82f1d804ec0de49, this proto message can probably be removed. We should do this in a separate PR. Signed-off-by: Thane Thomson <connect@thanethomson.com> * Lift termination condition into for loop Signed-off-by: Thane Thomson <connect@thanethomson.com> * Enforce vote extension signature requirement Signed-off-by: Thane Thomson <connect@thanethomson.com> * Expand on comment for PeekTwoBlocks for posterity Signed-off-by: Thane Thomson <connect@thanethomson.com> * Isolate TODO more clearly Signed-off-by: Thane Thomson <connect@thanethomson.com> * make mockery Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix comment Signed-off-by: Thane Thomson <connect@thanethomson.com> * Make panic output from BlockStore.SaveBlock more readable Signed-off-by: Thane Thomson <connect@thanethomson.com> * Add helper methods to ExtendedCommitSig and ExtendedCommit Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix most tests except TestHandshake* Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix store prefix collision Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix TestBlockFetchAtHeight Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove global state from store tests Signed-off-by: Thane Thomson <connect@thanethomson.com> * Apply suggestions from code review Co-authored-by: M. J. Fromberger <fromberger@interchain.io> Co-authored-by: Sergio Mena <sergio@informal.systems> * blocksync: Just return error Signed-off-by: Thane Thomson <connect@thanethomson.com> * make format Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Remove unused/commented-out code Signed-off-by: Thane Thomson <connect@thanethomson.com> * blocksync: Change pool AddBlock function signature to return errors Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Improve legibility of switch statements Signed-off-by: Thane Thomson <connect@thanethomson.com> * blocksync: Expand on extended commit requirement in AddBlock description Signed-off-by: Thane Thomson <connect@thanethomson.com> * blocksync: Return error without also logging it Signed-off-by: Thane Thomson <connect@thanethomson.com> * consensus: Rename short-lived local variable Signed-off-by: Thane Thomson <connect@thanethomson.com> * consensus: Allocate TODO to Sergio Signed-off-by: Thane Thomson <connect@thanethomson.com> * evidence/pool_test: Inline slice construction Signed-off-by: Thane Thomson <connect@thanethomson.com> * state: Rename LoadBlockExtCommit to LoadBlockExtendedCommit Signed-off-by: Thane Thomson <connect@thanethomson.com> * proto: Remove TODO on TxResult Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Minor format Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Reformat ExtendedCommitSig.BlockID Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Remove NewExtendedCommit constructor Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Remove NewCommit constructor Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Shorten receiver names for ExtendedCommit Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Convert ExtendedCommit.Copy to a deep clone Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Assign TODO to Sergio Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Fix legibility nits Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Improve legibility Signed-off-by: Thane Thomson <connect@thanethomson.com> * store/state: Add TODO to move prefixes to common package Signed-off-by: Thane Thomson <connect@thanethomson.com> * Propagate validator info to PrepareProposal In order to propagate validator voting power through to PrepareProposal, we need to load the validator set info from the height corresponding to the extended commit that we're passing through to PrepareProposal as the "LocalLastCommit". Signed-off-by: Thane Thomson <connect@thanethomson.com> * Rename local var for clarity Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix TestMaxProposalBlockSize Signed-off-by: Thane Thomson <connect@thanethomson.com> * Rename local var for clarity Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove debug log Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove CommigSig.ForBlock helper Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove CommigSig.Absent helper Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove ExtendedCommitSig.ForBlock helper Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove ExtendedCommitSig.Absent helper Signed-off-by: Thane Thomson <connect@thanethomson.com> * There are no extended commits below the initial height Signed-off-by: Thane Thomson <connect@thanethomson.com> * Fix comment grammar Signed-off-by: Thane Thomson <connect@thanethomson.com> * Remove JSON encoding from ExtendedCommit Signed-off-by: Thane Thomson <connect@thanethomson.com> * Embed CommitSig into ExtendedCommitSig instead of duplicating fields Signed-off-by: Thane Thomson <connect@thanethomson.com> * Rename ExtendedCommit vote_extension field to extension for consistency with domain types Signed-off-by: Thane Thomson <connect@thanethomson.com> * blocksync: Panic if we peek a block without an extended commit Signed-off-by: Thane Thomson <connect@thanethomson.com> * Apply suggestions from code review Co-authored-by: M. J. Fromberger <fromberger@interchain.io> * Remove Sergio from TODO Signed-off-by: Thane Thomson <connect@thanethomson.com> * Increase hard-coded vote extension max size to 1MB Signed-off-by: Thane Thomson <connect@thanethomson.com> * state: Remove unnecessary comment Signed-off-by: Thane Thomson <connect@thanethomson.com> * state: Ensure no of commit sigs equals validator set length Signed-off-by: Thane Thomson <connect@thanethomson.com> * make format Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Minor legibility improvements Signed-off-by: Thane Thomson <connect@thanethomson.com> * Improve legibility Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Remove unused GetVotes function on VoteSet Signed-off-by: Thane Thomson <connect@thanethomson.com> * Refactor TestMaxProposalBlockSize to construct more realistic extended commit Signed-off-by: Thane Thomson <connect@thanethomson.com> * Refactor buildExtendedCommitInfo to resemble buildLastCommitInfo Signed-off-by: Thane Thomson <connect@thanethomson.com> * Apply suggestions from code review Co-authored-by: M. J. Fromberger <fromberger@interchain.io> * abci++: Disable VerifyVoteExtension call on nil precommits (#8491) Signed-off-by: Thane Thomson <connect@thanethomson.com> * types: Require vote extensions on non-nil precommits and not otherwise Signed-off-by: Thane Thomson <connect@thanethomson.com> * Disable lint Signed-off-by: Thane Thomson <connect@thanethomson.com> * Increase timeout for TestReactorVotingPowerChange to counter flakiness Signed-off-by: Thane Thomson <connect@thanethomson.com> * Only sign and verify vote extensions in non-nil precommits Signed-off-by: Thane Thomson <connect@thanethomson.com> * Revert "Disable lint" This reverts commit 6fffbf9402. Signed-off-by: Thane Thomson <connect@thanethomson.com> * Add missing non-nil check uncovered non-deterministically in TestHandshakeReplayAll Signed-off-by: Thane Thomson <connect@thanethomson.com> * Expand error message for accuracy Signed-off-by: Thane Thomson <connect@thanethomson.com> * Only call ExtendVote when we make non-nil precommits Signed-off-by: Thane Thomson <connect@thanethomson.com> * Revert "Increase timeout for TestReactorVotingPowerChange to counter flakiness" This reverts commit af514939db. Signed-off-by: Thane Thomson <connect@thanethomson.com> * Refactor ValidateBasic for ExtendedCommitSig for legibility Signed-off-by: Thane Thomson <connect@thanethomson.com> Co-authored-by: Sergio Mena <sergio@informal.systems> Co-authored-by: M. J. Fromberger <fromberger@interchain.io>
2026-09-19 22:44:24 +00:00 · 2022-05-11 07:10:32 -04:00
parent 735a1a537b
commit 06b1812094
53 changed files with 1928 additions and 692 deletions
@@ -200,16 +200,20 @@ func (pool *BlockPool) IsCaughtUp() bool {
 	return pool.height >= (pool.maxPeerHeight - 1)
 }

-// PeekTwoBlocks returns blocks at pool.height and pool.height+1.
-// We need to see the second block's Commit to validate the first block.
-// So we peek two blocks at a time.
+// PeekTwoBlocks returns blocks at pool.height and pool.height+1. We need to
+// see the second block's Commit to validate the first block. So we peek two
+// blocks at a time. We return an extended commit, containing vote extensions
+// and their associated signatures, as this is critical to consensus in ABCI++
+// as we switch from block sync to consensus mode.
+//
 // The caller will verify the commit.
-func (pool *BlockPool) PeekTwoBlocks() (first *types.Block, second *types.Block) {
+func (pool *BlockPool) PeekTwoBlocks() (first, second *types.Block, firstExtCommit *types.ExtendedCommit) {
 	pool.mtx.RLock()
 	defer pool.mtx.RUnlock()

 	if r := pool.requesters[pool.height]; r != nil {
 		first = r.getBlock()
+		firstExtCommit = r.getExtendedCommit()
 	}
 	if r := pool.requesters[pool.height+1]; r != nil {
 		second = r.getBlock()
@@ -218,7 +222,8 @@ func (pool *BlockPool) PeekTwoBlocks() (first *types.Block, second *types.Block)
 }

 // PopRequest pops the first block at pool.height.
-// It must have been validated by 'second'.Commit from PeekTwoBlocks().
+// It must have been validated by the second Commit from PeekTwoBlocks.
+// TODO(thane): (?) and its corresponding ExtendedCommit.
 func (pool *BlockPool) PopRequest() {
 	pool.mtx.Lock()
 	defer pool.mtx.Unlock()
@@ -262,16 +267,25 @@ func (pool *BlockPool) RedoRequest(height int64) types.NodeID {
 	return peerID
 }

-// AddBlock validates that the block comes from the peer it was expected from and calls the requester to store it.
+// AddBlock validates that the block comes from the peer it was expected from
+// and calls the requester to store it.
+//
+// This requires an extended commit at the same height as the supplied block -
+// the block contains the last commit, but we need the latest commit in case we
+// need to switch over from block sync to consensus at this height. If the
+// height of the extended commit and the height of the block do not match, we
+// do not add the block and return an error.
 // TODO: ensure that blocks come in order for each peer.
-func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, blockSize int) {
+func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, extCommit *types.ExtendedCommit, blockSize int) error {
 	pool.mtx.Lock()
 	defer pool.mtx.Unlock()

+	if block.Height != extCommit.Height {
+		return fmt.Errorf("heights don't match, not adding block (block height: %d, commit height: %d)", block.Height, extCommit.Height)
+	}
+
 	requester := pool.requesters[block.Height]
 	if requester == nil {
-		pool.logger.Error("peer sent us a block we didn't expect",
-			"peer", peerID, "curHeight", pool.height, "blockHeight", block.Height)
 		diff := pool.height - block.Height
 		if diff < 0 {
 			diff *= -1
@@ -279,10 +293,10 @@ func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, blockSi
 		if diff > maxDiffBetweenCurrentAndReceivedBlockHeight {
 			pool.sendError(errors.New("peer sent us a block we didn't expect with a height too far ahead/behind"), peerID)
 		}
-		return
+		return fmt.Errorf("peer sent us a block we didn't expect (peer: %s, current height: %d, block height: %d)", peerID, pool.height, block.Height)
 	}

-	if requester.setBlock(block, peerID) {
+	if requester.setBlock(block, extCommit, peerID) {
 		atomic.AddInt32(&pool.numPending, -1)
 		peer := pool.peers[peerID]
 		if peer != nil {
@@ -290,9 +304,11 @@ func (pool *BlockPool) AddBlock(peerID types.NodeID, block *types.Block, blockSi
 		}
 	} else {
 		err := errors.New("requester is different or block already exists")
-		pool.logger.Error(err.Error(), "peer", peerID, "requester", requester.getPeerID(), "blockHeight", block.Height)
 		pool.sendError(err, peerID)
+		return fmt.Errorf("%w (peer: %s, requester: %s, block height: %d)", err, peerID, requester.getPeerID(), block.Height)
 	}
+
+	return nil
 }

 // MaxPeerHeight returns the highest reported height.
@@ -456,6 +472,7 @@ func (pool *BlockPool) debug() string {
 		} else {
 			str += fmt.Sprintf("H(%v):", h)
 			str += fmt.Sprintf("B?(%v) ", pool.requesters[h].block != nil)
+			str += fmt.Sprintf("C?(%v) ", pool.requesters[h].extCommit != nil)
 		}
 	}
 	return str
@@ -544,9 +561,10 @@ type bpRequester struct {
 	gotBlockCh chan struct{}
 	redoCh     chan types.NodeID // redo may send multitime, add peerId to identify repeat

-	mtx    sync.Mutex
-	peerID types.NodeID
-	block  *types.Block
+	mtx       sync.Mutex
+	peerID    types.NodeID
+	block     *types.Block
+	extCommit *types.ExtendedCommit
 }

 func newBPRequester(logger log.Logger, pool *BlockPool, height int64) *bpRequester {
@@ -572,13 +590,14 @@ func (bpr *bpRequester) OnStart(ctx context.Context) error {
 func (*bpRequester) OnStop() {}

 // Returns true if the peer matches and block doesn't already exist.
-func (bpr *bpRequester) setBlock(block *types.Block, peerID types.NodeID) bool {
+func (bpr *bpRequester) setBlock(block *types.Block, extCommit *types.ExtendedCommit, peerID types.NodeID) bool {
 	bpr.mtx.Lock()
 	if bpr.block != nil || bpr.peerID != peerID {
 		bpr.mtx.Unlock()
 		return false
 	}
 	bpr.block = block
+	bpr.extCommit = extCommit
 	bpr.mtx.Unlock()

 	select {
@@ -594,6 +613,12 @@ func (bpr *bpRequester) getBlock() *types.Block {
 	return bpr.block
 }

+func (bpr *bpRequester) getExtendedCommit() *types.ExtendedCommit {
+	bpr.mtx.Lock()
+	defer bpr.mtx.Unlock()
+	return bpr.extCommit
+}
+
 func (bpr *bpRequester) getPeerID() types.NodeID {
 	bpr.mtx.Lock()
 	defer bpr.mtx.Unlock()
@@ -611,6 +636,7 @@ func (bpr *bpRequester) reset() {

 	bpr.peerID = ""
 	bpr.block = nil
+	bpr.extCommit = nil
 }

 // Tells bpRequester to pick another peer and try again.
@@ -43,7 +43,10 @@ func (p testPeer) runInputRoutine() {
 // Request desired, pretend like we got the block immediately.
 func (p testPeer) simulateInput(input inputData) {
 	block := &types.Block{Header: types.Header{Height: input.request.Height}}
-	input.pool.AddBlock(input.request.PeerID, block, 123)
+	extCommit := &types.ExtendedCommit{
+		Height: input.request.Height,
+	}
+	_ = input.pool.AddBlock(input.request.PeerID, block, extCommit, 123)
 	// TODO: uncommenting this creates a race which is detected by:
 	// https://github.com/golang/go/blob/2bd767b1022dd3254bcec469f0ee164024726486/src/testing/testing.go#L854-L856
 	// see: https://github.com/tendermint/tendermint/issues/3390#issue-418379890
@@ -110,7 +113,7 @@ func TestBlockPoolBasic(t *testing.T) {
 			if !pool.IsRunning() {
 				return
 			}
-			first, second := pool.PeekTwoBlocks()
+			first, second, _ := pool.PeekTwoBlocks()
 			if first != nil && second != nil {
 				pool.PopRequest()
 			} else {
@@ -164,7 +167,7 @@ func TestBlockPoolTimeout(t *testing.T) {
 			if !pool.IsRunning() {
 				return
 			}
-			first, second := pool.PeekTwoBlocks()
+			first, second, _ := pool.PeekTwoBlocks()
 			if first != nil && second != nil {
 				pool.PopRequest()
 			} else {
@@ -76,7 +76,7 @@ type Reactor struct {
 	stateStore sm.Store

 	blockExec   *sm.BlockExecutor
-	store       *store.BlockStore
+	store       sm.BlockStore
 	pool        *BlockPool
 	consReactor consensusReactor
 	blockSync   *atomicBool
@@ -186,15 +186,21 @@ func (r *Reactor) OnStop() {
 func (r *Reactor) respondToPeer(ctx context.Context, msg *bcproto.BlockRequest, peerID types.NodeID, blockSyncCh *p2p.Channel) error {
 	block := r.store.LoadBlock(msg.Height)
 	if block != nil {
+		extCommit := r.store.LoadBlockExtendedCommit(msg.Height)
+		if extCommit == nil {
+			return fmt.Errorf("found block in store without extended commit: %v", block)
+		}
 		blockProto, err := block.ToProto()
 		if err != nil {
-			r.logger.Error("failed to convert msg to protobuf", "err", err)
-			return err
+			return fmt.Errorf("failed to convert block to protobuf: %w", err)
 		}

 		return blockSyncCh.Send(ctx, p2p.Envelope{
-			To:      peerID,
-			Message: &bcproto.BlockResponse{Block: blockProto},
+			To: peerID,
+			Message: &bcproto.BlockResponse{
+				Block:     blockProto,
+				ExtCommit: extCommit.ToProto(),
+			},
 		})
 	}

@@ -236,8 +242,17 @@ func (r *Reactor) handleMessage(ctx context.Context, envelope *p2p.Envelope, blo
 					"err", err)
 				return err
 			}
+			extCommit, err := types.ExtendedCommitFromProto(msg.ExtCommit)
+			if err != nil {
+				r.logger.Error("failed to convert extended commit from proto",
+					"peer", envelope.From,
+					"err", err)
+				return err
+			}

-			r.pool.AddBlock(envelope.From, block, block.Size())
+			if err := r.pool.AddBlock(envelope.From, block, extCommit, block.Size()); err != nil {
+				r.logger.Error("failed to add block", "err", err)
+			}

 		case *bcproto.StatusRequest:
 			return blockSyncCh.Send(ctx, p2p.Envelope{
@@ -448,6 +463,20 @@ func (r *Reactor) poolRoutine(ctx context.Context, stateSynced bool, blockSyncCh
 			)

 			switch {
+			// TODO(sergio) Might be needed for implementing the upgrading solution. Remove after that
+			//case state.LastBlockHeight > 0 && r.store.LoadBlockExtCommit(state.LastBlockHeight) == nil:
+			case state.LastBlockHeight > 0 && blocksSynced == 0:
+				// Having state-synced, we need to blocksync at least one block
+				r.logger.Info(
+					"no seen commit yet",
+					"height", height,
+					"last_block_height", state.LastBlockHeight,
+					"initial_height", state.InitialHeight,
+					"max_peer_height", r.pool.MaxPeerHeight(),
+					"timeout_in", syncTimeout-time.Since(lastAdvance),
+				)
+				continue
+
 			case r.pool.IsCaughtUp():
 				r.logger.Info("switching to consensus reactor", "height", height)

@@ -490,9 +519,13 @@ func (r *Reactor) poolRoutine(ctx context.Context, stateSynced bool, blockSyncCh
 			// TODO: Uncouple from request routine.

 			// see if there are any blocks to sync
-			first, second := r.pool.PeekTwoBlocks()
-			if first == nil || second == nil {
-				// we need both to sync the first block
+			first, second, extCommit := r.pool.PeekTwoBlocks()
+			if first == nil || second == nil || extCommit == nil {
+				if first != nil && extCommit == nil {
+					// See https://github.com/tendermint/tendermint/pull/8433#discussion_r866790631
+					panic(fmt.Errorf("peeked first block without extended commit at height %d - possible node store corruption", first.Height))
+				}
+				// we need all to sync the first block
 				continue
 			} else {
 				// try again quickly next loop
@@ -517,6 +550,7 @@ func (r *Reactor) poolRoutine(ctx context.Context, stateSynced bool, blockSyncCh
 			// NOTE: We can probably make this more efficient, but note that calling
 			// first.Hash() doesn't verify the tx contents, so MakePartSet() is
 			// currently necessary.
+			// TODO(sergio): Should we also validate against the extended commit?
 			err = state.Validators.VerifyCommitLight(chainID, firstID, first.Height, second.LastCommit)

 			if err == nil {
@@ -559,7 +593,7 @@ func (r *Reactor) poolRoutine(ctx context.Context, stateSynced bool, blockSyncCh
 			r.pool.PopRequest()

 			// TODO: batch saves so we do not persist to disk every block
-			r.store.SaveBlock(first, firstParts, second.LastCommit)
+			r.store.SaveBlock(first, firstParts, extCommit)

 			// TODO: Same thing for app - but we would need a way to get the hash
 			// without persisting the state.
@@ -147,39 +147,43 @@ func (rts *reactorTestSuite) addNode(
 		sm.NopMetrics(),
 	)

+	var lastExtCommit *types.ExtendedCommit
+
+	// The commit we are building for the current height.
+	seenExtCommit := &types.ExtendedCommit{}
+
 	for blockHeight := int64(1); blockHeight <= maxBlockHeight; blockHeight++ {
-		lastCommit := types.NewCommit(blockHeight-1, 0, types.BlockID{}, nil)
+		lastExtCommit = seenExtCommit.Clone()

-		if blockHeight > 1 {
-			lastBlockMeta := blockStore.LoadBlockMeta(blockHeight - 1)
-			lastBlock := blockStore.LoadBlock(blockHeight - 1)
-
-			vote, err := factory.MakeVote(
-				ctx,
-				privVal,
-				lastBlock.Header.ChainID, 0,
-				lastBlock.Header.Height, 0, 2,
-				lastBlockMeta.BlockID,
-				time.Now(),
-			)
-			require.NoError(t, err)
-			lastCommit = types.NewCommit(
-				vote.Height,
-				vote.Round,
-				lastBlockMeta.BlockID,
-				[]types.CommitSig{vote.CommitSig()},
-			)
-		}
-
-		thisBlock := sf.MakeBlock(state, blockHeight, lastCommit)
+		thisBlock := sf.MakeBlock(state, blockHeight, lastExtCommit.StripExtensions())
 		thisParts, err := thisBlock.MakePartSet(types.BlockPartSizeBytes)
 		require.NoError(t, err)
 		blockID := types.BlockID{Hash: thisBlock.Hash(), PartSetHeader: thisParts.Header()}

+		// Simulate a commit for the current height
+		vote, err := factory.MakeVote(
+			ctx,
+			privVal,
+			thisBlock.Header.ChainID,
+			0,
+			thisBlock.Header.Height,
+			0,
+			2,
+			blockID,
+			time.Now(),
+		)
+		require.NoError(t, err)
+		seenExtCommit = &types.ExtendedCommit{
+			Height:             vote.Height,
+			Round:              vote.Round,
+			BlockID:            blockID,
+			ExtendedSignatures: []types.ExtendedCommitSig{vote.ExtendedCommitSig()},
+		}
+
 		state, err = blockExec.ApplyBlock(ctx, state, blockID, thisBlock)
 		require.NoError(t, err)

-		blockStore.SaveBlock(thisBlock, thisParts, lastCommit)
+		blockStore.SaveBlock(thisBlock, thisParts, seenExtCommit)
 	}

 	rts.peerChans[nodeID] = make(chan p2p.PeerUpdate)
@@ -178,22 +178,22 @@ func TestByzantinePrevoteEquivocation(t *testing.T) {
 	lazyNodeState.decideProposal = func(ctx context.Context, height int64, round int32) {
 		require.NotNil(t, lazyNodeState.privValidator)

-		var commit *types.Commit
+		var extCommit *types.ExtendedCommit
 		switch {
 		case lazyNodeState.Height == lazyNodeState.state.InitialHeight:
 			// We're creating a proposal for the first block.
 			// The commit is empty, but not nil.
-			commit = types.NewCommit(0, 0, types.BlockID{}, nil)
+			extCommit = &types.ExtendedCommit{}
 		case lazyNodeState.LastCommit.HasTwoThirdsMajority():
 			// Make the commit from LastCommit
-			commit = lazyNodeState.LastCommit.MakeCommit()
+			extCommit = lazyNodeState.LastCommit.MakeExtendedCommit()
 		default: // This shouldn't happen.
 			lazyNodeState.logger.Error("enterPropose: Cannot propose anything: No commit for the previous block")
 			return
 		}

 		// omit the last signature in the commit
-		commit.Signatures[len(commit.Signatures)-1] = types.NewCommitSigAbsent()
+		extCommit.ExtendedSignatures[len(extCommit.ExtendedSignatures)-1] = types.NewExtendedCommitSigAbsent()

 		if lazyNodeState.privValidatorPubKey == nil {
 			// If this node is a validator & proposer in the current round, it will
@@ -204,7 +204,7 @@ func TestByzantinePrevoteEquivocation(t *testing.T) {
 		proposerAddr := lazyNodeState.privValidatorPubKey.Address()

 		block, err := lazyNodeState.blockExec.CreateProposalBlock(
-			ctx, lazyNodeState.Height, lazyNodeState.state, commit, proposerAddr, lazyNodeState.LastCommit.GetVotes())
+			ctx, lazyNodeState.Height, lazyNodeState.state, extCommit, proposerAddr)
 		require.NoError(t, err)
 		blockParts, err := block.MakePartSet(types.BlockPartSizeBytes)
 		require.NoError(t, err)
@@ -160,7 +160,8 @@ func signVote(
 	blockID types.BlockID) *types.Vote {

 	var ext []byte
-	if voteType == tmproto.PrecommitType {
+	// Only non-nil precommits are allowed to carry vote extensions.
+	if voteType == tmproto.PrecommitType && !blockID.IsNil() {
 		ext = []byte("extension")
 	}
 	v, err := vs.signVote(ctx, voteType, chainID, blockID, ext)
@@ -6,6 +6,7 @@ import (
 	testing "testing"

 	mock "github.com/stretchr/testify/mock"
+
 	state "github.com/tendermint/tendermint/internal/state"
 )

@@ -67,7 +67,7 @@ func TestMsgToProto(t *testing.T) {

 	pv := types.NewMockPV()
 	vote, err := factory.MakeVote(ctx, pv, factory.DefaultTestChainID,
-		0, 1, 0, 2, types.BlockID{}, time.Now())
+		0, 1, 0, 2, bi, time.Now())
 	require.NoError(t, err)
 	pbVote := vote.ToProto()

@@ -794,10 +794,10 @@ func (r *Reactor) gossipVotesRoutine(ctx context.Context, ps *PeerState, voteCh
 		// catchup logic -- if peer is lagging by more than 1, send Commit
 		blockStoreBase := r.state.blockStore.Base()
 		if blockStoreBase > 0 && prs.Height != 0 && rs.Height >= prs.Height+2 && prs.Height >= blockStoreBase {
-			// Load the block commit for prs.Height, which contains precommit
+			// Load the block's extended commit for prs.Height, which contains precommit
 			// signatures for prs.Height.
-			if commit := r.state.blockStore.LoadBlockCommit(prs.Height); commit != nil {
-				if ok, err := r.pickSendVote(ctx, ps, commit, voteCh); err != nil {
+			if ec := r.state.blockStore.LoadBlockExtendedCommit(prs.Height); ec != nil {
+				if ok, err := r.pickSendVote(ctx, ps, ec, voteCh); err != nil {
 					return
 				} else if ok {
 					logger.Debug("picked Catchup commit to send", "height", prs.Height)
@@ -297,7 +297,7 @@ type simulatorTestSuite struct {
 	GenesisState sm.State
 	Config       *config.Config
 	Chain        []*types.Block
-	Commits      []*types.Commit
+	ExtCommits   []*types.ExtendedCommit
 	CleanupFunc  cleanupFunc

 	Mempool mempool.Mempool
@@ -578,11 +578,11 @@ func setupSimulator(ctx context.Context, t *testing.T) *simulatorTestSuite {
 	}
 	ensureNewRound(t, newRoundCh, height+1, 0)

-	sim.Chain = make([]*types.Block, 0)
-	sim.Commits = make([]*types.Commit, 0)
+	sim.Chain = []*types.Block{}
+	sim.ExtCommits = []*types.ExtendedCommit{}
 	for i := 1; i <= numBlocks; i++ {
 		sim.Chain = append(sim.Chain, css[0].blockStore.LoadBlock(int64(i)))
-		sim.Commits = append(sim.Commits, css[0].blockStore.LoadBlockCommit(int64(i)))
+		sim.ExtCommits = append(sim.ExtCommits, css[0].blockStore.LoadBlockExtendedCommit(int64(i)))
 	}

 	return sim
@@ -679,7 +679,7 @@ func testHandshakeReplay(
 	testValidatorsChange bool,
 ) {
 	var chain []*types.Block
-	var commits []*types.Commit
+	var extCommits []*types.ExtendedCommit
 	var store *mockBlockStore
 	var stateDB dbm.DB
 	var genesisState sm.State
@@ -699,7 +699,7 @@ func testHandshakeReplay(
 		genesisState = sim.GenesisState
 		cfg = sim.Config
 		chain = append([]*types.Block{}, sim.Chain...) // copy chain
-		commits = sim.Commits
+		extCommits = sim.ExtCommits
 		store = newMockBlockStore(t, cfg, genesisState.ConsensusParams)
 	} else { // test single node
 		testConfig, err := ResetConfig(t.TempDir(), fmt.Sprintf("%s_%v_s", t.Name(), mode))
@@ -718,7 +718,7 @@ func testHandshakeReplay(
 		err = wal.Start(ctx)
 		require.NoError(t, err)
 		t.Cleanup(func() { cancel(); wal.Wait() })
-		chain, commits = makeBlockchainFromWAL(t, wal)
+		chain, extCommits = makeBlockchainFromWAL(t, wal)
 		pubKey, err := privVal.GetPubKey(ctx)
 		require.NoError(t, err)
 		stateDB, genesisState, store = stateAndStore(t, cfg, pubKey, kvstore.ProtocolVersion)
@@ -726,7 +726,7 @@ func testHandshakeReplay(
 	}
 	stateStore := sm.NewStore(stateDB)
 	store.chain = chain
-	store.commits = commits
+	store.extCommits = extCommits

 	state := genesisState.Copy()
 	// run the chain through state.ApplyBlock to build up the tendermint state
@@ -1034,7 +1034,7 @@ func (app *badApp) Commit(context.Context) (*abci.ResponseCommit, error) {
 //--------------------------
 // utils for making blocks

-func makeBlockchainFromWAL(t *testing.T, wal WAL) ([]*types.Block, []*types.Commit) {
+func makeBlockchainFromWAL(t *testing.T, wal WAL) ([]*types.Block, []*types.ExtendedCommit) {
 	t.Helper()
 	var height int64

@@ -1047,10 +1047,10 @@ func makeBlockchainFromWAL(t *testing.T, wal WAL) ([]*types.Block, []*types.Comm
 	// log.Notice("Build a blockchain by reading from the WAL")

 	var (
-		blocks          []*types.Block
-		commits         []*types.Commit
-		thisBlockParts  *types.PartSet
-		thisBlockCommit *types.Commit
+		blocks             []*types.Block
+		extCommits         []*types.ExtendedCommit
+		thisBlockParts     *types.PartSet
+		thisBlockExtCommit *types.ExtendedCommit
 	)

 	dec := NewWALDecoder(gr)
@@ -1082,12 +1082,12 @@ func makeBlockchainFromWAL(t *testing.T, wal WAL) ([]*types.Block, []*types.Comm
 				require.Equal(t, block.Height, height+1,
 					"read bad block from wal. got height %d, expected %d", block.Height, height+1)

-				commitHeight := thisBlockCommit.Height
+				commitHeight := thisBlockExtCommit.Height
 				require.Equal(t, commitHeight, height+1,
 					"commit doesnt match. got height %d, expected %d", commitHeight, height+1)

 				blocks = append(blocks, block)
-				commits = append(commits, thisBlockCommit)
+				extCommits = append(extCommits, thisBlockExtCommit)
 				height++
 			}
 		case *types.PartSetHeader:
@@ -1097,8 +1097,12 @@ func makeBlockchainFromWAL(t *testing.T, wal WAL) ([]*types.Block, []*types.Comm
 			require.NoError(t, err)
 		case *types.Vote:
 			if p.Type == tmproto.PrecommitType {
-				thisBlockCommit = types.NewCommit(p.Height, p.Round,
-					p.BlockID, []types.CommitSig{p.CommitSig()})
+				thisBlockExtCommit = &types.ExtendedCommit{
+					Height:             p.Height,
+					Round:              p.Round,
+					BlockID:            p.BlockID,
+					ExtendedSignatures: []types.ExtendedCommitSig{p.ExtendedCommitSig()},
+				}
 			}
 		}
 	}
@@ -1113,12 +1117,12 @@ func makeBlockchainFromWAL(t *testing.T, wal WAL) ([]*types.Block, []*types.Comm
 	require.NoError(t, err)

 	require.Equal(t, block.Height, height+1, "read bad block from wal. got height %d, expected %d", block.Height, height+1)
-	commitHeight := thisBlockCommit.Height
+	commitHeight := thisBlockExtCommit.Height
 	require.Equal(t, commitHeight, height+1, "commit does not match. got height %d, expected %d", commitHeight, height+1)

 	blocks = append(blocks, block)
-	commits = append(commits, thisBlockCommit)
-	return blocks, commits
+	extCommits = append(extCommits, thisBlockExtCommit)
+	return blocks, extCommits
 }

 func readPieceFromWAL(msg *TimedWALMessage) interface{} {
@@ -1162,14 +1166,16 @@ func stateAndStore(
 // mock block store

 type mockBlockStore struct {
-	cfg     *config.Config
-	params  types.ConsensusParams
-	chain   []*types.Block
-	commits []*types.Commit
-	base    int64
-	t       *testing.T
+	cfg        *config.Config
+	params     types.ConsensusParams
+	chain      []*types.Block
+	extCommits []*types.ExtendedCommit
+	base       int64
+	t          *testing.T
 }

+var _ sm.BlockStore = &mockBlockStore{}
+
 // TODO: NewBlockStore(db.NewMemDB) ...
 func newMockBlockStore(t *testing.T, cfg *config.Config, params types.ConsensusParams) *mockBlockStore {
 	return &mockBlockStore{
@@ -1198,20 +1204,24 @@ func (bs *mockBlockStore) LoadBlockMeta(height int64) *types.BlockMeta {
 	}
 }
 func (bs *mockBlockStore) LoadBlockPart(height int64, index int) *types.Part { return nil }
-func (bs *mockBlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.Commit) {
+func (bs *mockBlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.ExtendedCommit) {
 }
+
 func (bs *mockBlockStore) LoadBlockCommit(height int64) *types.Commit {
-	return bs.commits[height-1]
+	return bs.extCommits[height-1].StripExtensions()
 }
 func (bs *mockBlockStore) LoadSeenCommit() *types.Commit {
-	return bs.commits[len(bs.commits)-1]
+	return bs.extCommits[len(bs.extCommits)-1].StripExtensions()
+}
+func (bs *mockBlockStore) LoadBlockExtendedCommit(height int64) *types.ExtendedCommit {
+	return bs.extCommits[height-1]
 }

 func (bs *mockBlockStore) PruneBlocks(height int64) (uint64, error) {
 	pruned := uint64(0)
 	for i := int64(0); i < height-1; i++ {
 		bs.chain[i] = nil
-		bs.commits[i] = nil
+		bs.extCommits[i] = nil
 		pruned++
 	}
 	bs.base = height
@@ -695,19 +695,15 @@ func (cs *State) sendInternalMessage(ctx context.Context, mi msgInfo) {
 // Reconstruct LastCommit from SeenCommit, which we saved along with the block,
 // (which happens even before saving the state)
 func (cs *State) reconstructLastCommit(state sm.State) {
-	commit := cs.blockStore.LoadSeenCommit()
-	if commit == nil || commit.Height != state.LastBlockHeight {
-		commit = cs.blockStore.LoadBlockCommit(state.LastBlockHeight)
-	}
-
-	if commit == nil {
+	extCommit := cs.blockStore.LoadBlockExtendedCommit(state.LastBlockHeight)
+	if extCommit == nil {
 		panic(fmt.Sprintf(
 			"failed to reconstruct last commit; commit for height %v not found",
 			state.LastBlockHeight,
 		))
 	}

-	lastPrecommits := types.CommitToVoteSet(state.ChainID, commit, state.LastValidators)
+	lastPrecommits := extCommit.ToVoteSet(state.ChainID, state.LastValidators)
 	if !lastPrecommits.HasTwoThirdsMajority() {
 		panic("failed to reconstruct last commit; does not have +2/3 maj")
 	}
@@ -1401,16 +1397,17 @@ func (cs *State) createProposalBlock(ctx context.Context) (*types.Block, error)
 		return nil, errors.New("entered createProposalBlock with privValidator being nil")
 	}

-	var commit *types.Commit
+	// TODO(sergio): wouldn't it be easier if CreateProposalBlock accepted cs.LastCommit directly?
+	var lastExtCommit *types.ExtendedCommit
 	switch {
 	case cs.Height == cs.state.InitialHeight:
 		// We're creating a proposal for the first block.
 		// The commit is empty, but not nil.
-		commit = types.NewCommit(0, 0, types.BlockID{}, nil)
+		lastExtCommit = &types.ExtendedCommit{}

 	case cs.LastCommit.HasTwoThirdsMajority():
 		// Make the commit from LastCommit
-		commit = cs.LastCommit.MakeCommit()
+		lastExtCommit = cs.LastCommit.MakeExtendedCommit()

 	default: // This shouldn't happen.
 		cs.logger.Error("propose step; cannot propose anything without commit for the previous block")
@@ -1426,7 +1423,7 @@ func (cs *State) createProposalBlock(ctx context.Context) (*types.Block, error)

 	proposerAddr := cs.privValidatorPubKey.Address()

-	ret, err := cs.blockExec.CreateProposalBlock(ctx, cs.Height, cs.state, commit, proposerAddr, cs.LastCommit.GetVotes())
+	ret, err := cs.blockExec.CreateProposalBlock(ctx, cs.Height, cs.state, lastExtCommit, proposerAddr)
 	if err != nil {
 		panic(err)
 	}
@@ -1925,8 +1922,7 @@ func (cs *State) finalizeCommit(ctx context.Context, height int64) {
 		// NOTE: the seenCommit is local justification to commit this block,
 		// but may differ from the LastCommit included in the next block
 		precommits := cs.Votes.Precommits(cs.CommitRound)
-		seenCommit := precommits.MakeCommit()
-		cs.blockStore.SaveBlock(block, blockParts, seenCommit)
+		cs.blockStore.SaveBlock(block, blockParts, precommits.MakeExtendedCommit())
 	} else {
 		// Happens during replay if we already saved the block but didn't commit
 		logger.Debug("calling finalizeCommit on already stored block", "height", block.Height)
@@ -2028,7 +2024,7 @@ func (cs *State) RecordMetrics(height int64, block *types.Block) {

 		for i, val := range cs.LastValidators.Validators {
 			commitSig := block.LastCommit.Signatures[i]
-			if commitSig.Absent() {
+			if commitSig.BlockIDFlag == types.BlockIDFlagAbsent {
 				missingValidators++
 				missingValidatorsPower += val.VotingPower
 			}
@@ -2038,7 +2034,7 @@ func (cs *State) RecordMetrics(height int64, block *types.Block) {
 					"validator_address", val.Address.String(),
 				}
 				cs.metrics.ValidatorPower.With(label...).Set(float64(val.VotingPower))
-				if commitSig.ForBlock() {
+				if commitSig.BlockIDFlag == types.BlockIDFlagCommit {
 					cs.metrics.ValidatorLastSignedHeight.With(label...).Set(float64(height))
 				} else {
 					cs.metrics.ValidatorMissedBlocks.With(label...).Add(float64(1))
@@ -2341,8 +2337,9 @@ func (cs *State) addVote(
 		return
 	}

-	// Verify VoteExtension if precommit
-	if vote.Type == tmproto.PrecommitType {
+	// Verify VoteExtension if precommit and not nil
+	// https://github.com/tendermint/tendermint/issues/8487
+	if vote.Type == tmproto.PrecommitType && !vote.BlockID.IsNil() {
 		err := cs.blockExec.VerifyVoteExtension(ctx, vote)
 		cs.metrics.MarkVoteExtensionReceived(err == nil)
 		if err != nil {
@@ -2497,15 +2494,15 @@ func (cs *State) signVote(
 	// use our local precommit Timeout as the max wait time for getting a singed commit. The same goes for prevote.
 	timeout := cs.voteTimeout(cs.Round)

-	switch msgType {
-	case tmproto.PrecommitType:
-		// if the signedMessage type is for a precommit, add VoteExtension
+	if msgType == tmproto.PrecommitType && !vote.BlockID.IsNil() {
+		// if the signedMessage type is for a non-nil precommit, add
+		// VoteExtension
 		ext, err := cs.blockExec.ExtendVote(ctx, vote)
 		if err != nil {
 			return nil, err
 		}
 		vote.Extension = ext
-	default:
+	} else {
 		timeout = time.Second
 	}

@@ -1950,7 +1950,7 @@ func TestFinalizeBlockCalled(t *testing.T) {
 		expectCalled bool
 	}{
 		{
-			name:         "finalze block called when block committed",
+			name:         "finalize block called when block committed",
 			voteNil:      false,
 			expectCalled: true,
 		},
@@ -1970,11 +1970,15 @@ func TestFinalizeBlockCalled(t *testing.T) {
 				Status: abci.ResponseProcessProposal_ACCEPT,
 			}, nil)
 			m.On("PrepareProposal", mock.Anything, mock.Anything).Return(&abci.ResponsePrepareProposal{}, nil)
-			m.On("VerifyVoteExtension", mock.Anything, mock.Anything).Return(&abci.ResponseVerifyVoteExtension{
-				Status: abci.ResponseVerifyVoteExtension_ACCEPT,
-			}, nil)
+			// We only expect VerifyVoteExtension to be called on non-nil precommits.
+			// https://github.com/tendermint/tendermint/issues/8487
+			if !testCase.voteNil {
+				m.On("ExtendVote", mock.Anything, mock.Anything).Return(&abci.ResponseExtendVote{}, nil)
+				m.On("VerifyVoteExtension", mock.Anything, mock.Anything).Return(&abci.ResponseVerifyVoteExtension{
+					Status: abci.ResponseVerifyVoteExtension_ACCEPT,
+				}, nil)
+			}
 			m.On("FinalizeBlock", mock.Anything, mock.Anything).Return(&abci.ResponseFinalizeBlock{}, nil).Maybe()
-			m.On("ExtendVote", mock.Anything, mock.Anything).Return(&abci.ResponseExtendVote{}, nil)
 			m.On("Commit", mock.Anything).Return(&abci.ResponseCommit{}, nil).Maybe()

 			cs1, vss := makeState(ctx, t, makeStateArgs{config: config, application: m})
@@ -249,8 +249,8 @@ func TestEvidencePoolUpdate(t *testing.T) {
 		evidenceChainID,
 	)
 	require.NoError(t, err)
-	lastCommit := makeCommit(height, val.PrivKey.PubKey().Address())
-	block := types.MakeBlock(height+1, []types.Tx{}, lastCommit, []types.Evidence{ev})
+	lastExtCommit := makeExtCommit(height, val.PrivKey.PubKey().Address())
+	block := types.MakeBlock(height+1, []types.Tx{}, lastExtCommit.StripExtensions(), []types.Evidence{ev})

 	// update state (partially)
 	state.LastBlockHeight = height + 1
@@ -568,8 +568,8 @@ func initializeBlockStore(db dbm.DB, state sm.State, valAddr []byte) (*store.Blo
 	blockStore := store.NewBlockStore(db)

 	for i := int64(1); i <= state.LastBlockHeight; i++ {
-		lastCommit := makeCommit(i-1, valAddr)
-		block := sf.MakeBlock(state, i, lastCommit)
+		lastCommit := makeExtCommit(i-1, valAddr)
+		block := sf.MakeBlock(state, i, lastCommit.StripExtensions())

 		block.Header.Time = defaultEvidenceTime.Add(time.Duration(i) * time.Minute)
 		block.Header.Version = version.Consensus{Block: version.BlockProtocol, App: 1}
@@ -579,22 +579,25 @@ func initializeBlockStore(db dbm.DB, state sm.State, valAddr []byte) (*store.Blo
 			return nil, err
 		}

-		seenCommit := makeCommit(i, valAddr)
+		seenCommit := makeExtCommit(i, valAddr)
 		blockStore.SaveBlock(block, partSet, seenCommit)
 	}

 	return blockStore, nil
 }

-func makeCommit(height int64, valAddr []byte) *types.Commit {
-	commitSigs := []types.CommitSig{{
-		BlockIDFlag:      types.BlockIDFlagCommit,
-		ValidatorAddress: valAddr,
-		Timestamp:        defaultEvidenceTime,
-		Signature:        []byte("Signature"),
-	}}
-
-	return types.NewCommit(height, 0, types.BlockID{}, commitSigs)
+func makeExtCommit(height int64, valAddr []byte) *types.ExtendedCommit {
+	return &types.ExtendedCommit{
+		Height: height,
+		ExtendedSignatures: []types.ExtendedCommitSig{{
+			CommitSig: types.CommitSig{
+				BlockIDFlag:      types.BlockIDFlagCommit,
+				ValidatorAddress: valAddr,
+				Timestamp:        defaultEvidenceTime,
+				Signature:        []byte("Signature"),
+			},
+		}},
+	}
 }

 func defaultTestPool(ctx context.Context, t *testing.T, height int64) (*evidence.Pool, types.MockPV, *eventbus.EventBus) {
@@ -234,8 +234,9 @@ func TestVerifyLightClientAttack_Equivocation(t *testing.T) {
 	// except the last validator vote twice
 	blockID := factory.MakeBlockIDWithHash(conflictingHeader.Hash())
 	voteSet := types.NewVoteSet(evidenceChainID, 10, 1, tmproto.SignedMsgType(2), conflictingVals)
-	commit, err := factory.MakeCommit(ctx, blockID, 10, 1, voteSet, conflictingPrivVals[:4], defaultEvidenceTime)
+	extCommit, err := factory.MakeExtendedCommit(ctx, blockID, 10, 1, voteSet, conflictingPrivVals[:4], defaultEvidenceTime)
 	require.NoError(t, err)
+	commit := extCommit.StripExtensions()

 	ev := &types.LightClientAttackEvidence{
 		ConflictingBlock: &types.LightBlock{
@@ -253,9 +254,10 @@ func TestVerifyLightClientAttack_Equivocation(t *testing.T) {

 	trustedBlockID := makeBlockID(trustedHeader.Hash(), 1000, []byte("partshash"))
 	trustedVoteSet := types.NewVoteSet(evidenceChainID, 10, 1, tmproto.SignedMsgType(2), conflictingVals)
-	trustedCommit, err := factory.MakeCommit(ctx, trustedBlockID, 10, 1,
+	trustedExtCommit, err := factory.MakeExtendedCommit(ctx, trustedBlockID, 10, 1,
 		trustedVoteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
+	trustedCommit := trustedExtCommit.StripExtensions()

 	trustedSignedHeader := &types.SignedHeader{
 		Header: trustedHeader,
@@ -335,8 +337,9 @@ func TestVerifyLightClientAttack_Amnesia(t *testing.T) {
 	// except the last validator vote twice. However this time the commits are of different rounds.
 	blockID := makeBlockID(conflictingHeader.Hash(), 1000, []byte("partshash"))
 	voteSet := types.NewVoteSet(evidenceChainID, height, 0, tmproto.SignedMsgType(2), conflictingVals)
-	commit, err := factory.MakeCommit(ctx, blockID, height, 0, voteSet, conflictingPrivVals, defaultEvidenceTime)
+	extCommit, err := factory.MakeExtendedCommit(ctx, blockID, height, 0, voteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
+	commit := extCommit.StripExtensions()

 	ev := &types.LightClientAttackEvidence{
 		ConflictingBlock: &types.LightBlock{
@@ -354,9 +357,10 @@ func TestVerifyLightClientAttack_Amnesia(t *testing.T) {

 	trustedBlockID := makeBlockID(trustedHeader.Hash(), 1000, []byte("partshash"))
 	trustedVoteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), conflictingVals)
-	trustedCommit, err := factory.MakeCommit(ctx, trustedBlockID, height, 1,
+	trustedExtCommit, err := factory.MakeExtendedCommit(ctx, trustedBlockID, height, 1,
 		trustedVoteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
+	trustedCommit := trustedExtCommit.StripExtensions()

 	trustedSignedHeader := &types.SignedHeader{
 		Header: trustedHeader,
@@ -550,8 +554,9 @@ func makeLunaticEvidence(

 	blockID := factory.MakeBlockIDWithHash(conflictingHeader.Hash())
 	voteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), conflictingVals)
-	commit, err := factory.MakeCommit(ctx, blockID, height, 1, voteSet, conflictingPrivVals, defaultEvidenceTime)
+	extCommit, err := factory.MakeExtendedCommit(ctx, blockID, height, 1, voteSet, conflictingPrivVals, defaultEvidenceTime)
 	require.NoError(t, err)
+	commit := extCommit.StripExtensions()

 	ev = &types.LightClientAttackEvidence{
 		ConflictingBlock: &types.LightBlock{
@@ -578,8 +583,9 @@ func makeLunaticEvidence(
 	trustedBlockID := factory.MakeBlockIDWithHash(trustedHeader.Hash())
 	trustedVals, privVals := factory.ValidatorSet(ctx, t, totalVals, defaultVotingPower)
 	trustedVoteSet := types.NewVoteSet(evidenceChainID, height, 1, tmproto.SignedMsgType(2), trustedVals)
-	trustedCommit, err := factory.MakeCommit(ctx, trustedBlockID, height, 1, trustedVoteSet, privVals, defaultEvidenceTime)
+	trustedExtCommit, err := factory.MakeExtendedCommit(ctx, trustedBlockID, height, 1, trustedVoteSet, privVals, defaultEvidenceTime)
 	require.NoError(t, err)
+	trustedCommit := trustedExtCommit.StripExtensions()

 	trusted = &types.LightBlock{
 		SignedHeader: &types.SignedHeader{
@@ -1,13 +1,13 @@
 package state

 import (
+	"bytes"
 	"context"
 	"fmt"
 	"time"

 	abciclient "github.com/tendermint/tendermint/abci/client"
 	abci "github.com/tendermint/tendermint/abci/types"
-	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/encoding"
 	"github.com/tendermint/tendermint/crypto/merkle"
 	"github.com/tendermint/tendermint/internal/eventbus"
@@ -87,9 +87,8 @@ func (blockExec *BlockExecutor) CreateProposalBlock(
 	ctx context.Context,
 	height int64,
 	state State,
-	commit *types.Commit,
+	lastExtCommit *types.ExtendedCommit,
 	proposerAddr []byte,
-	votes []*types.Vote,
 ) (*types.Block, error) {

 	maxBytes := state.ConsensusParams.Block.MaxBytes
@@ -101,15 +100,15 @@ func (blockExec *BlockExecutor) CreateProposalBlock(
 	maxDataBytes := types.MaxDataBytes(maxBytes, evSize, state.Validators.Size())

 	txs := blockExec.mempool.ReapMaxBytesMaxGas(maxDataBytes, maxGas)
+	commit := lastExtCommit.StripExtensions()
 	block := state.MakeBlock(height, txs, commit, evidence, proposerAddr)

-	localLastCommit := buildLastCommitInfo(block, blockExec.store, state.InitialHeight)
 	rpp, err := blockExec.appClient.PrepareProposal(
 		ctx,
 		&abci.RequestPrepareProposal{
 			MaxTxBytes:          maxDataBytes,
 			Txs:                 block.Txs.ToSliceOfBytes(),
-			LocalLastCommit:     extendedCommitInfo(localLastCommit, votes),
+			LocalLastCommit:     buildExtendedCommitInfo(lastExtCommit, blockExec.store, state.InitialHeight),
 			ByzantineValidators: block.Evidence.ToABCI(),
 			Height:              block.Height,
 			Time:                block.Time,
@@ -381,14 +380,14 @@ func (blockExec *BlockExecutor) Commit(

 func buildLastCommitInfo(block *types.Block, store Store, initialHeight int64) abci.CommitInfo {
 	if block.Height == initialHeight {
-		// there is no last commmit for the initial height.
+		// there is no last commit for the initial height.
 		// return an empty value.
 		return abci.CommitInfo{}
 	}

 	lastValSet, err := store.LoadValidators(block.Height - 1)
 	if err != nil {
-		panic(err)
+		panic(fmt.Errorf("failed to load validator set at height %d: %w", block.Height-1, err))
 	}

 	var (
@@ -410,7 +409,7 @@ func buildLastCommitInfo(block *types.Block, store Store, initialHeight int64) a
 		commitSig := block.LastCommit.Signatures[i]
 		votes[i] = abci.VoteInfo{
 			Validator:       types.TM2PB.Validator(val),
-			SignedLastBlock: !commitSig.Absent(),
+			SignedLastBlock: commitSig.BlockIDFlag != types.BlockIDFlagAbsent,
 		}
 	}

@@ -420,44 +419,69 @@ func buildLastCommitInfo(block *types.Block, store Store, initialHeight int64) a
 	}
 }

-// extendedCommitInfo expects a CommitInfo struct along with all of the
-// original votes relating to that commit, including their vote extensions. The
-// order of votes does not matter.
-func extendedCommitInfo(c abci.CommitInfo, votes []*types.Vote) abci.ExtendedCommitInfo {
-	if len(c.Votes) != len(votes) {
-		panic(fmt.Sprintf("extendedCommitInfo: number of votes from commit differ from the number of votes supplied (%d != %d)", len(c.Votes), len(votes)))
+// buildExtendedCommitInfo populates an ABCI extended commit from the
+// corresponding Tendermint extended commit ec, using the stored validator set
+// from ec.  It requires ec to include the original precommit votes along with
+// the vote extensions from the last commit.
+//
+// For heights below the initial height, for which we do not have the required
+// data, it returns an empty record.
+//
+// Assumes that the commit signatures are sorted according to validator index.
+func buildExtendedCommitInfo(ec *types.ExtendedCommit, store Store, initialHeight int64) abci.ExtendedCommitInfo {
+	if ec.Height < initialHeight {
+		// There are no extended commits for heights below the initial height.
+		return abci.ExtendedCommitInfo{}
 	}
-	votesByVal := make(map[string]*types.Vote)
-	for _, vote := range votes {
-		if vote != nil {
-			valAddr := vote.ValidatorAddress.String()
-			if _, ok := votesByVal[valAddr]; ok {
-				panic(fmt.Sprintf("extendedCommitInfo: found duplicate vote for validator with address %s", valAddr))
-			}
-			votesByVal[valAddr] = vote
+
+	valSet, err := store.LoadValidators(ec.Height)
+	if err != nil {
+		panic(fmt.Errorf("failed to load validator set at height %d, initial height %d: %w", ec.Height, initialHeight, err))
+	}
+
+	var (
+		ecSize    = ec.Size()
+		valSetLen = len(valSet.Validators)
+	)
+
+	// Ensure that the size of the validator set in the extended commit matches
+	// the size of the validator set in the state store.
+	if ecSize != valSetLen {
+		panic(fmt.Errorf(
+			"extended commit size (%d) does not match validator set length (%d) at height %d\n\n%v\n\n%v",
+			ecSize, valSetLen, ec.Height, ec.ExtendedSignatures, valSet.Validators,
+		))
+	}
+
+	votes := make([]abci.ExtendedVoteInfo, ecSize)
+	for i, val := range valSet.Validators {
+		ecs := ec.ExtendedSignatures[i]
+
+		// Absent signatures have empty validator addresses, but otherwise we
+		// expect the validator addresses to be the same.
+		if ecs.BlockIDFlag != types.BlockIDFlagAbsent && !bytes.Equal(ecs.ValidatorAddress, val.Address) {
+			panic(fmt.Errorf("validator address of extended commit signature in position %d (%s) does not match the corresponding validator's at height %d (%s)",
+				i, ecs.ValidatorAddress, ec.Height, val.Address,
+			))
 		}
-	}
-	vs := make([]abci.ExtendedVoteInfo, len(c.Votes))
-	for i := range vs {
+
 		var ext []byte
-		// votes[i] will be nil if c.Votes[i].SignedLastBlock is false
-		if c.Votes[i].SignedLastBlock {
-			valAddr := crypto.Address(c.Votes[i].Validator.Address).String()
-			vote, ok := votesByVal[valAddr]
-			if !ok || vote == nil {
-				panic(fmt.Sprintf("extendedCommitInfo: validator with address %s signed last block, but could not find vote for it", valAddr))
-			}
-			ext = vote.Extension
+		if ecs.BlockIDFlag == types.BlockIDFlagCommit {
+			// We only care about vote extensions if a validator has voted to
+			// commit.
+			ext = ecs.Extension
 		}
-		vs[i] = abci.ExtendedVoteInfo{
-			Validator:       c.Votes[i].Validator,
-			SignedLastBlock: c.Votes[i].SignedLastBlock,
+
+		votes[i] = abci.ExtendedVoteInfo{
+			Validator:       types.TM2PB.Validator(val),
+			SignedLastBlock: ecs.BlockIDFlag != types.BlockIDFlagAbsent,
 			VoteExtension:   ext,
 		}
 	}
+
 	return abci.ExtendedCommitInfo{
-		Round: c.Round,
-		Votes: vs,
+		Round: ec.Round,
+		Votes: votes,
 	}
 }

@@ -79,9 +79,10 @@ func TestApplyBlock(t *testing.T) {
 	assert.EqualValues(t, 1, state.Version.Consensus.App, "App version wasn't updated")
 }

-// TestFinalizeBlockDecidedLastCommit ensures we correctly send the DecidedLastCommit to the
-// application. The test ensures that the DecidedLastCommit properly reflects
-// which validators signed the preceding block.
+// TestFinalizeBlockDecidedLastCommit ensures we correctly send the
+// DecidedLastCommit to the application. The test ensures that the
+// DecidedLastCommit properly reflects which validators signed the preceding
+// block.
 func TestFinalizeBlockDecidedLastCommit(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -96,7 +97,7 @@ func TestFinalizeBlockDecidedLastCommit(t *testing.T) {

 	state, stateDB, privVals := makeState(t, 7, 1)
 	stateStore := sm.NewStore(stateDB)
-	absentSig := types.NewCommitSigAbsent()
+	absentSig := types.NewExtendedCommitSigAbsent()

 	testCases := []struct {
 		name             string
@@ -134,12 +135,12 @@ func TestFinalizeBlockDecidedLastCommit(t *testing.T) {

 			for idx, isAbsent := range tc.absentCommitSigs {
 				if isAbsent {
-					lastCommit.Signatures[idx] = absentSig
+					lastCommit.ExtendedSignatures[idx] = absentSig
 				}
 			}

 			// block for height 2
-			block := sf.MakeBlock(state, 2, lastCommit)
+			block := sf.MakeBlock(state, 2, lastCommit.StripExtensions())
 			bps, err := block.MakePartSet(testPartSize)
 			require.NoError(t, err)
 			blockID := types.BlockID{Hash: block.Hash(), PartSetHeader: bps.Header()}
@@ -198,12 +199,15 @@ func TestFinalizeBlockByzantineValidators(t *testing.T) {
 		ConflictingBlock: &types.LightBlock{
 			SignedHeader: &types.SignedHeader{
 				Header: header,
-				Commit: types.NewCommit(10, 0, makeBlockID(header.Hash(), 100, []byte("partshash")), []types.CommitSig{{
-					BlockIDFlag:      types.BlockIDFlagNil,
-					ValidatorAddress: crypto.AddressHash([]byte("validator_address")),
-					Timestamp:        defaultEvidenceTime,
-					Signature:        crypto.CRandBytes(types.MaxSignatureSize),
-				}}),
+				Commit: &types.Commit{
+					Height:  10,
+					BlockID: makeBlockID(header.Hash(), 100, []byte("partshash")),
+					Signatures: []types.CommitSig{{
+						BlockIDFlag:      types.BlockIDFlagNil,
+						ValidatorAddress: crypto.AddressHash([]byte("validator_address")),
+						Timestamp:        defaultEvidenceTime,
+						Signature:        crypto.CRandBytes(types.MaxSignatureSize)}},
+				},
 			},
 			ValidatorSet: state.Validators,
 		},
@@ -324,8 +328,10 @@ func TestProcessProposal(t *testing.T) {
 		lastCommitSig = append(lastCommitSig, vote.CommitSig())
 	}

-	lastCommit := types.NewCommit(height-1, 0, types.BlockID{}, lastCommitSig)
-	block1 := sf.MakeBlock(state, height, lastCommit)
+	block1 := sf.MakeBlock(state, height, &types.Commit{
+		Height:     height - 1,
+		Signatures: lastCommitSig,
+	})
 	block1.Txs = txs

 	expectedRpp := &abci.RequestProcessProposal{
@@ -653,8 +659,8 @@ func TestEmptyPrepareProposal(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-	_, err = blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	_, err = blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.NoError(t, err)
 }

@@ -708,8 +714,8 @@ func TestPrepareProposalErrorOnNonExistingRemoved(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.ErrorContains(t, err, "new transaction incorrectly marked as removed")
 	require.Nil(t, block)

@@ -764,8 +770,8 @@ func TestPrepareProposalRemoveTxs(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.NoError(t, err)
 	require.Len(t, block.Data.Txs.ToSliceOfBytes(), len(trs)-2)

@@ -823,8 +829,8 @@ func TestPrepareProposalAddedTxsIncluded(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.NoError(t, err)

 	require.Equal(t, txs[0], block.Data.Txs[0])
@@ -879,8 +885,8 @@ func TestPrepareProposalReorderTxs(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.NoError(t, err)
 	for i, tx := range block.Data.Txs {
 		require.Equal(t, types.Tx(trs[i].Tx), tx)
@@ -939,9 +945,8 @@ func TestPrepareProposalErrorOnTooManyTxs(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-
-	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.ErrorContains(t, err, "transaction data size exceeds maximum")
 	require.Nil(t, block, "")

@@ -991,9 +996,8 @@ func TestPrepareProposalErrorOnPrepareProposalError(t *testing.T) {
 		sm.NopMetrics(),
 	)
 	pa, _ := state.Validators.GetByIndex(0)
-	commit, votes := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
-
-	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa, votes)
+	commit, _ := makeValidCommit(ctx, t, height, types.BlockID{}, state.Validators, privVals)
+	block, err := blockExec.CreateProposalBlock(ctx, height, state, commit, pa)
 	require.Nil(t, block)
 	require.ErrorContains(t, err, "an injected error")

@@ -39,7 +39,7 @@ func makeAndCommitGoodBlock(
 	blockExec *sm.BlockExecutor,
 	privVals map[string]types.PrivValidator,
 	evidence []types.Evidence,
-) (sm.State, types.BlockID, *types.Commit) {
+) (sm.State, types.BlockID, *types.ExtendedCommit) {
 	t.Helper()

 	// A good block passes
@@ -82,19 +82,23 @@ func makeValidCommit(
 	blockID types.BlockID,
 	vals *types.ValidatorSet,
 	privVals map[string]types.PrivValidator,
-) (*types.Commit, []*types.Vote) {
+) (*types.ExtendedCommit, []*types.Vote) {
 	t.Helper()
-	sigs := make([]types.CommitSig, vals.Size())
+	sigs := make([]types.ExtendedCommitSig, vals.Size())
 	votes := make([]*types.Vote, vals.Size())
 	for i := 0; i < vals.Size(); i++ {
 		_, val := vals.GetByIndex(int32(i))
 		vote, err := factory.MakeVote(ctx, privVals[val.Address.String()], chainID, int32(i), height, 0, 2, blockID, time.Now())
 		require.NoError(t, err)
-		sigs[i] = vote.CommitSig()
+		sigs[i] = vote.ExtendedCommitSig()
 		votes[i] = vote
 	}

-	return types.NewCommit(height, 0, blockID, sigs), votes
+	return &types.ExtendedCommit{
+		Height:             height,
+		BlockID:            blockID,
+		ExtendedSignatures: sigs,
+	}, votes
 }

 func makeState(t *testing.T, nVals, height int) (sm.State, dbm.DB, map[string]types.PrivValidator) {
@@ -6,6 +6,7 @@ import (
 	context "context"

 	mock "github.com/stretchr/testify/mock"
+
 	indexer "github.com/tendermint/tendermint/internal/state/indexer"

 	query "github.com/tendermint/tendermint/internal/pubsub/query"
@@ -107,6 +107,22 @@ func (_m *BlockStore) LoadBlockCommit(height int64) *types.Commit {
 	return r0
 }

+// LoadBlockExtendedCommit provides a mock function with given fields: height
+func (_m *BlockStore) LoadBlockExtendedCommit(height int64) *types.ExtendedCommit {
+	ret := _m.Called(height)
+
+	var r0 *types.ExtendedCommit
+	if rf, ok := ret.Get(0).(func(int64) *types.ExtendedCommit); ok {
+		r0 = rf(height)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*types.ExtendedCommit)
+		}
+	}
+
+	return r0
+}
+
 // LoadBlockMeta provides a mock function with given fields: height
 func (_m *BlockStore) LoadBlockMeta(height int64) *types.BlockMeta {
 	ret := _m.Called(height)
@@ -193,7 +209,7 @@ func (_m *BlockStore) PruneBlocks(height int64) (uint64, error) {
 }

 // SaveBlock provides a mock function with given fields: block, blockParts, seenCommit
-func (_m *BlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.Commit) {
+func (_m *BlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.ExtendedCommit) {
 	_m.Called(block, blockParts, seenCommit)
 }

@@ -6,6 +6,7 @@ import (
 	context "context"

 	mock "github.com/stretchr/testify/mock"
+
 	state "github.com/tendermint/tendermint/internal/state"

 	testing "testing"
@@ -4,6 +4,7 @@ package mocks

 import (
 	mock "github.com/stretchr/testify/mock"
+
 	state "github.com/tendermint/tendermint/internal/state"
 	tendermintstate "github.com/tendermint/tendermint/proto/tendermint/state"

@@ -26,7 +26,7 @@ type BlockStore interface {
 	LoadBlockMeta(height int64) *types.BlockMeta
 	LoadBlock(height int64) *types.Block

-	SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.Commit)
+	SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.ExtendedCommit)

 	PruneBlocks(height int64) (uint64, error)

@@ -36,6 +36,7 @@ type BlockStore interface {

 	LoadBlockCommit(height int64) *types.Commit
 	LoadSeenCommit() *types.Commit
+	LoadBlockExtendedCommit(height int64) *types.ExtendedCommit
 }

 //-----------------------------------------------------------------------------
@@ -26,6 +26,9 @@ const (

 //------------------------------------------------------------------------

+// NB: Before modifying these, cross-check them with those in
+// internal/store/store.go
+// TODO(thane): Move these and the ones in internal/store/store.go to their own package.
 const (
 	// prefixes are unique across all tm db's
 	prefixValidators      = int64(5)
@@ -63,7 +63,7 @@ func makeBlockAndPartSet(
 ) (*types.Block, *types.PartSet) {
 	t.Helper()

-	lastCommit := types.NewCommit(height-1, 0, types.BlockID{}, nil)
+	lastCommit := &types.Commit{Height: height - 1}
 	if height > 1 {
 		vote, err := factory.MakeVote(
 			ctx,
@@ -73,8 +73,12 @@ func makeBlockAndPartSet(
 			lastBlockMeta.BlockID,
 			time.Now())
 		require.NoError(t, err)
-		lastCommit = types.NewCommit(vote.Height, vote.Round,
-			lastBlockMeta.BlockID, []types.CommitSig{vote.CommitSig()})
+		lastCommit = &types.Commit{
+			Height:     vote.Height,
+			Round:      vote.Round,
+			BlockID:    lastBlock.LastBlockID,
+			Signatures: []types.CommitSig{vote.CommitSig()},
+		}
 	}

 	block := state.MakeBlock(height, []types.Tx{}, lastCommit, nil, state.Validators.GetProposer().Address)
@@ -65,7 +65,8 @@ func TestValidateBlockHeader(t *testing.T) {
 		eventBus,
 		sm.NopMetrics(),
 	)
-	lastCommit := types.NewCommit(0, 0, types.BlockID{}, nil)
+	lastCommit := &types.Commit{}
+	var lastExtCommit *types.ExtendedCommit

 	// some bad values
 	wrongHash := crypto.Checksum([]byte("this hash is wrong"))
@@ -100,7 +101,7 @@ func TestValidateBlockHeader(t *testing.T) {
 		{"Proposer invalid", func(block *types.Block) { block.ProposerAddress = []byte("wrong size") }},

 		{"first LastCommit contains signatures", func(block *types.Block) {
-			block.LastCommit = types.NewCommit(0, 0, types.BlockID{}, []types.CommitSig{types.NewCommitSigAbsent()})
+			block.LastCommit = &types.Commit{Signatures: []types.CommitSig{types.NewCommitSigAbsent()}}
 			block.LastCommitHash = block.LastCommit.Hash()
 		}},
 	}
@@ -121,8 +122,9 @@ func TestValidateBlockHeader(t *testing.T) {
 		/*
 			A good block passes
 		*/
-		state, _, lastCommit = makeAndCommitGoodBlock(ctx, t,
+		state, _, lastExtCommit = makeAndCommitGoodBlock(ctx, t,
 			state, height, lastCommit, state.Validators.GetProposer().Address, blockExec, privVals, nil)
+		lastCommit = lastExtCommit.StripExtensions()
 	}

 	nextHeight := validationTestsStopHeight
@@ -169,8 +171,9 @@ func TestValidateBlockCommit(t *testing.T) {
 		eventBus,
 		sm.NopMetrics(),
 	)
-	lastCommit := types.NewCommit(0, 0, types.BlockID{}, nil)
-	wrongSigsCommit := types.NewCommit(1, 0, types.BlockID{}, nil)
+	lastCommit := &types.Commit{}
+	var lastExtCommit *types.ExtendedCommit
+	wrongSigsCommit := &types.Commit{Height: 1}
 	badPrivVal := types.NewMockPV()

 	for height := int64(1); height < validationTestsStopHeight; height++ {
@@ -192,12 +195,12 @@ func TestValidateBlockCommit(t *testing.T) {
 				time.Now(),
 			)
 			require.NoError(t, err)
-			wrongHeightCommit := types.NewCommit(
-				wrongHeightVote.Height,
-				wrongHeightVote.Round,
-				state.LastBlockID,
-				[]types.CommitSig{wrongHeightVote.CommitSig()},
-			)
+			wrongHeightCommit := &types.Commit{
+				Height:     wrongHeightVote.Height,
+				Round:      wrongHeightVote.Round,
+				BlockID:    state.LastBlockID,
+				Signatures: []types.CommitSig{wrongHeightVote.CommitSig()},
+			}
 			block := statefactory.MakeBlock(state, height, wrongHeightCommit)
 			err = blockExec.ValidateBlock(ctx, state, block)
 			_, isErrInvalidCommitHeight := err.(types.ErrInvalidCommitHeight)
@@ -220,7 +223,7 @@ func TestValidateBlockCommit(t *testing.T) {
 			A good block passes
 		*/
 		var blockID types.BlockID
-		state, blockID, lastCommit = makeAndCommitGoodBlock(
+		state, blockID, lastExtCommit = makeAndCommitGoodBlock(
 			ctx,
 			t,
 			state,
@@ -231,6 +234,7 @@ func TestValidateBlockCommit(t *testing.T) {
 			privVals,
 			nil,
 		)
+		lastCommit = lastExtCommit.StripExtensions()

 		/*
 			wrongSigsCommit is fine except for the extra bad precommit
@@ -270,8 +274,12 @@ func TestValidateBlockCommit(t *testing.T) {

 		goodVote.Signature, badVote.Signature = g.Signature, b.Signature

-		wrongSigsCommit = types.NewCommit(goodVote.Height, goodVote.Round,
-			blockID, []types.CommitSig{goodVote.CommitSig(), badVote.CommitSig()})
+		wrongSigsCommit = &types.Commit{
+			Height:     goodVote.Height,
+			Round:      goodVote.Round,
+			BlockID:    blockID,
+			Signatures: []types.CommitSig{goodVote.CommitSig(), badVote.CommitSig()},
+		}
 	}
 }

@@ -319,7 +327,8 @@ func TestValidateBlockEvidence(t *testing.T) {
 		eventBus,
 		sm.NopMetrics(),
 	)
-	lastCommit := types.NewCommit(0, 0, types.BlockID{}, nil)
+	lastCommit := &types.Commit{}
+	var lastExtCommit *types.ExtendedCommit

 	for height := int64(1); height < validationTestsStopHeight; height++ {
 		proposerAddr := state.Validators.GetProposer().Address
@@ -364,7 +373,7 @@ func TestValidateBlockEvidence(t *testing.T) {
 			evidence = append(evidence, newEv)
 		}

-		state, _, lastCommit = makeAndCommitGoodBlock(
+		state, _, lastExtCommit = makeAndCommitGoodBlock(
 			ctx,
 			t,
 			state,
@@ -375,6 +384,7 @@ func TestValidateBlockEvidence(t *testing.T) {
 			privVals,
 			evidence,
 		)
+		lastCommit = lastExtCommit.StripExtensions()

 	}
 }
@@ -6,6 +6,7 @@ import (
 	context "context"

 	mock "github.com/stretchr/testify/mock"
+
 	state "github.com/tendermint/tendermint/internal/state"

 	testing "testing"
@@ -856,12 +856,12 @@ func mockLB(ctx context.Context, t *testing.T, height int64, time time.Time, las
 	header.ConsensusHash = types.DefaultConsensusParams().HashConsensusParams()
 	lastBlockID = factory.MakeBlockIDWithHash(header.Hash())
 	voteSet := types.NewVoteSet(factory.DefaultTestChainID, height, 0, tmproto.PrecommitType, currentVals)
-	commit, err := factory.MakeCommit(ctx, lastBlockID, height, 0, voteSet, currentPrivVals, time)
+	extCommit, err := factory.MakeExtendedCommit(ctx, lastBlockID, height, 0, voteSet, currentPrivVals, time)
 	require.NoError(t, err)
 	return nextVals, nextPrivVals, &types.LightBlock{
 		SignedHeader: &types.SignedHeader{
 			Header: header,
-			Commit: commit,
+			Commit: extCommit.StripExtensions(),
 		},
 		ValidatorSet: currentVals,
 	}
@@ -273,11 +273,31 @@ func (bs *BlockStore) LoadBlockCommit(height int64) *types.Commit {
 	}
 	commit, err := types.CommitFromProto(pbc)
 	if err != nil {
-		panic(fmt.Errorf("error reading block commit: %w", err))
+		panic(fmt.Errorf("converting commit to proto: %w", err))
 	}
 	return commit
 }

+func (bs *BlockStore) LoadBlockExtendedCommit(height int64) *types.ExtendedCommit {
+	pbec := new(tmproto.ExtendedCommit)
+	bz, err := bs.db.Get(extCommitKey(height))
+	if err != nil {
+		panic(fmt.Errorf("fetching extended commit: %w", err))
+	}
+	if len(bz) == 0 {
+		return nil
+	}
+	err = proto.Unmarshal(bz, pbec)
+	if err != nil {
+		panic(fmt.Errorf("decoding extended commit: %w", err))
+	}
+	extCommit, err := types.ExtendedCommitFromProto(pbec)
+	if err != nil {
+		panic(fmt.Errorf("converting extended commit: %w", err))
+	}
+	return extCommit
+}
+
 // LoadSeenCommit returns the last locally seen Commit before being
 // cannonicalized. This is useful when we've seen a commit, but there
 // has not yet been a new block at `height + 1` that includes this
@@ -298,7 +318,7 @@ func (bs *BlockStore) LoadSeenCommit() *types.Commit {

 	commit, err := types.CommitFromProto(pbc)
 	if err != nil {
-		panic(fmt.Errorf("error from proto commit: %w", err))
+		panic(fmt.Errorf("converting seen commit: %w", err))
 	}
 	return commit
 }
@@ -446,7 +466,7 @@ func (bs *BlockStore) batchDelete(
 //             If all the nodes restart after committing a block,
 //             we need this to reload the precommits to catch-up nodes to the
 //             most recent height.  Otherwise they'd stall at H-1.
-func (bs *BlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.Commit) {
+func (bs *BlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, seenCommit *types.ExtendedCommit) {
 	if block == nil {
 		panic("BlockStore can only save a non-nil block")
 	}
@@ -462,6 +482,10 @@ func (bs *BlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, s
 	if !blockParts.IsComplete() {
 		panic("BlockStore can only save complete block part sets")
 	}
+	if height != seenCommit.Height {
+		panic(fmt.Sprintf("BlockStore cannot save seen commit of a different height (block: %d, commit: %d)",
+			height, seenCommit.Height))
+	}

 	// Save block parts. This must be done before the block meta, since callers
 	// typically load the block meta first as an indication that the block exists
@@ -494,12 +518,18 @@ func (bs *BlockStore) SaveBlock(block *types.Block, blockParts *types.PartSet, s
 	}

 	// Save seen commit (seen +2/3 precommits for block)
-	pbsc := seenCommit.ToProto()
+	pbsc := seenCommit.StripExtensions().ToProto()
 	seenCommitBytes := mustEncode(pbsc)
 	if err := batch.Set(seenCommitKey(), seenCommitBytes); err != nil {
 		panic(err)
 	}

+	pbec := seenCommit.ToProto()
+	extCommitBytes := mustEncode(pbec)
+	if err := batch.Set(extCommitKey(height), extCommitBytes); err != nil {
+		panic(err)
+	}
+
 	if err := batch.WriteSync(); err != nil {
 		panic(err)
 	}
@@ -579,6 +609,9 @@ func (bs *BlockStore) Close() error {
 //---------------------------------- KEY ENCODING -----------------------------------------

 // key prefixes
+// NB: Before modifying these, cross-check them with those in
+// internal/state/store.go
+// TODO(thane): Move these and the ones in internal/state/store.go to their own package.
 const (
 	// prefixes are unique across all tm db's
 	prefixBlockMeta   = int64(0)
@@ -586,6 +619,7 @@ const (
 	prefixBlockCommit = int64(2)
 	prefixSeenCommit  = int64(3)
 	prefixBlockHash   = int64(4)
+	prefixExtCommit   = int64(9) // 5..8 are used by state/store
 )

 func blockMetaKey(height int64) []byte {
@@ -635,6 +669,14 @@ func seenCommitKey() []byte {
 	return key
 }

+func extCommitKey(height int64) []byte {
+	key, err := orderedcode.Append(nil, prefixExtCommit, height)
+	if err != nil {
+		panic(err)
+	}
+	return key
+}
+
 func blockHashKey(hash []byte) []byte {
 	key, err := orderedcode.Append(nil, prefixBlockHash, string(hash))
 	if err != nil {
@@ -2,7 +2,6 @@ package store

 import (
 	"fmt"
-	stdlog "log"
 	"os"
 	"runtime/debug"
 	"strings"
@@ -27,22 +26,25 @@ import (
 // test.
 type cleanupFunc func()

-// make a Commit with a single vote containing just the height and a timestamp
-func makeTestCommit(height int64, timestamp time.Time) *types.Commit {
-	commitSigs := []types.CommitSig{{
-		BlockIDFlag:      types.BlockIDFlagCommit,
-		ValidatorAddress: tmrand.Bytes(crypto.AddressSize),
-		Timestamp:        timestamp,
-		Signature:        []byte("Signature"),
+// make an extended commit with a single vote containing just the height and a
+// timestamp
+func makeTestExtCommit(height int64, timestamp time.Time) *types.ExtendedCommit {
+	extCommitSigs := []types.ExtendedCommitSig{{
+		CommitSig: types.CommitSig{
+			BlockIDFlag:      types.BlockIDFlagCommit,
+			ValidatorAddress: tmrand.Bytes(crypto.AddressSize),
+			Timestamp:        timestamp,
+			Signature:        []byte("Signature"),
+		},
 	}}
-	return types.NewCommit(
-		height,
-		0,
-		types.BlockID{
+	return &types.ExtendedCommit{
+		Height: height,
+		BlockID: types.BlockID{
 			Hash:          crypto.CRandBytes(32),
 			PartSetHeader: types.PartSetHeader{Hash: crypto.CRandBytes(32), Total: 2},
 		},
-		commitSigs)
+		ExtendedSignatures: extCommitSigs,
+	}
 }

 func makeStateAndBlockStore(dir string) (sm.State, *BlockStore, cleanupFunc, error) {
@@ -59,47 +61,11 @@ func makeStateAndBlockStore(dir string) (sm.State, *BlockStore, cleanupFunc, err
 	return state, NewBlockStore(blockDB), func() { os.RemoveAll(cfg.RootDir) }, nil
 }

-func freshBlockStore() (*BlockStore, dbm.DB) {
+func newInMemoryBlockStore() (*BlockStore, dbm.DB) {
 	db := dbm.NewMemDB()
 	return NewBlockStore(db), db
 }

-var (
-	state       sm.State
-	block       *types.Block
-	partSet     *types.PartSet
-	part1       *types.Part
-	part2       *types.Part
-	seenCommit1 *types.Commit
-)
-
-func TestMain(m *testing.M) {
-	dir, err := os.MkdirTemp("", "store_test")
-	if err != nil {
-		stdlog.Fatal(err)
-	}
-	var cleanup cleanupFunc
-
-	state, _, cleanup, err = makeStateAndBlockStore(dir)
-	if err != nil {
-		stdlog.Fatal(err)
-	}
-
-	block = factory.MakeBlock(state, 1, new(types.Commit))
-
-	partSet, err = block.MakePartSet(2)
-	if err != nil {
-		stdlog.Fatal(err)
-	}
-	part1 = partSet.GetPart(0)
-	part2 = partSet.GetPart(1)
-	seenCommit1 = makeTestCommit(10, tmtime.Now())
-	code := m.Run()
-	cleanup()
-	os.RemoveAll(dir) // best-effort
-	os.Exit(code)
-}
-
 // TODO: This test should be simplified ...
 func TestBlockStoreSaveLoadBlock(t *testing.T) {
 	state, bs, cleanup, err := makeStateAndBlockStore(t.TempDir())
@@ -120,8 +86,10 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 	block := factory.MakeBlock(state, bs.Height()+1, new(types.Commit))
 	validPartSet, err := block.MakePartSet(2)
 	require.NoError(t, err)
-	seenCommit := makeTestCommit(10, tmtime.Now())
-	bs.SaveBlock(block, partSet, seenCommit)
+	part2 := validPartSet.GetPart(1)
+
+	seenCommit := makeTestExtCommit(block.Header.Height, tmtime.Now())
+	bs.SaveBlock(block, validPartSet, seenCommit)
 	require.EqualValues(t, 1, bs.Base(), "expecting the new height to be changed")
 	require.EqualValues(t, block.Header.Height, bs.Height(), "expecting the new height to be changed")

@@ -139,11 +107,11 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 	}

 	// End of setup, test data
-	commitAtH10 := makeTestCommit(10, tmtime.Now())
+	commitAtH10 := makeTestExtCommit(10, tmtime.Now()).StripExtensions()
 	tuples := []struct {
 		block      *types.Block
 		parts      *types.PartSet
-		seenCommit *types.Commit
+		seenCommit *types.ExtendedCommit
 		wantPanic  string
 		wantErr    bool

@@ -156,7 +124,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 		{
 			block:      newBlock(header1, commitAtH10),
 			parts:      validPartSet,
-			seenCommit: seenCommit1,
+			seenCommit: seenCommit,
 		},

 		{
@@ -172,10 +140,10 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 					ChainID:         "block_test",
 					Time:            tmtime.Now(),
 					ProposerAddress: tmrand.Bytes(crypto.AddressSize)},
-				makeTestCommit(5, tmtime.Now()),
+				makeTestExtCommit(5, tmtime.Now()).StripExtensions(),
 			),
 			parts:      validPartSet,
-			seenCommit: makeTestCommit(5, tmtime.Now()),
+			seenCommit: makeTestExtCommit(5, tmtime.Now()),
 		},

 		{
@@ -187,7 +155,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 		{
 			block:             newBlock(header1, commitAtH10),
 			parts:             validPartSet,
-			seenCommit:        seenCommit1,
+			seenCommit:        seenCommit,
 			corruptCommitInDB: true, // Corrupt the DB's commit entry
 			wantPanic:         "error reading block commit",
 		},
@@ -195,7 +163,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 		{
 			block:            newBlock(header1, commitAtH10),
 			parts:            validPartSet,
-			seenCommit:       seenCommit1,
+			seenCommit:       seenCommit,
 			wantPanic:        "unmarshal to tmproto.BlockMeta",
 			corruptBlockInDB: true, // Corrupt the DB's block entry
 		},
@@ -203,7 +171,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 		{
 			block:      newBlock(header1, commitAtH10),
 			parts:      validPartSet,
-			seenCommit: seenCommit1,
+			seenCommit: seenCommit,

 			// Expecting no error and we want a nil back
 			eraseSeenCommitInDB: true,
@@ -212,7 +180,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 		{
 			block:      newBlock(header1, commitAtH10),
 			parts:      validPartSet,
-			seenCommit: seenCommit1,
+			seenCommit: seenCommit,

 			corruptSeenCommitInDB: true,
 			wantPanic:             "error reading block seen commit",
@@ -221,7 +189,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {
 		{
 			block:      newBlock(header1, commitAtH10),
 			parts:      validPartSet,
-			seenCommit: seenCommit1,
+			seenCommit: seenCommit,

 			// Expecting no error and we want a nil back
 			eraseCommitInDB: true,
@@ -238,7 +206,7 @@ func TestBlockStoreSaveLoadBlock(t *testing.T) {

 	for i, tuple := range tuples {
 		tuple := tuple
-		bs, db := freshBlockStore()
+		bs, db := newInMemoryBlockStore()
 		// SaveBlock
 		res, err, panicErr := doFn(func() (interface{}, error) {
 			bs.SaveBlock(tuple.block, tuple.parts, tuple.seenCommit)
@@ -324,7 +292,7 @@ func TestLoadBaseMeta(t *testing.T) {
 		block := factory.MakeBlock(state, h, new(types.Commit))
 		partSet, err := block.MakePartSet(2)
 		require.NoError(t, err)
-		seenCommit := makeTestCommit(h, tmtime.Now())
+		seenCommit := makeTestExtCommit(h, tmtime.Now())
 		bs.SaveBlock(block, partSet, seenCommit)
 	}

@@ -338,13 +306,19 @@ func TestLoadBaseMeta(t *testing.T) {
 }

 func TestLoadBlockPart(t *testing.T) {
-	bs, db := freshBlockStore()
-	height, index := int64(10), 1
+	cfg, err := config.ResetTestRoot(t.TempDir(), "blockchain_reactor_test")
+	require.NoError(t, err)
+
+	bs, db := newInMemoryBlockStore()
+	const height, index = 10, 1
 	loadPart := func() (interface{}, error) {
 		part := bs.LoadBlockPart(height, index)
 		return part, nil
 	}

+	state, err := sm.MakeGenesisStateFromFile(cfg.GenesisFile())
+	require.NoError(t, err)
+
 	// Initially no contents.
 	// 1. Requesting for a non-existent block shouldn't fail
 	res, _, panicErr := doFn(loadPart)
@@ -352,13 +326,18 @@ func TestLoadBlockPart(t *testing.T) {
 	require.Nil(t, res, "a non-existent block part should return nil")

 	// 2. Next save a corrupted block then try to load it
-	err := db.Set(blockPartKey(height, index), []byte("Tendermint"))
+	err = db.Set(blockPartKey(height, index), []byte("Tendermint"))
 	require.NoError(t, err)
 	res, _, panicErr = doFn(loadPart)
 	require.NotNil(t, panicErr, "expecting a non-nil panic")
 	require.Contains(t, panicErr.Error(), "unmarshal to tmproto.Part failed")

 	// 3. A good block serialized and saved to the DB should be retrievable
+	block := factory.MakeBlock(state, height, new(types.Commit))
+	partSet, err := block.MakePartSet(2)
+	require.NoError(t, err)
+	part1 := partSet.GetPart(0)
+
 	pb1, err := part1.ToProto()
 	require.NoError(t, err)
 	err = db.Set(blockPartKey(height, index), mustEncode(pb1))
@@ -391,7 +370,7 @@ func TestPruneBlocks(t *testing.T) {
 		block := factory.MakeBlock(state, h, new(types.Commit))
 		partSet, err := block.MakePartSet(2)
 		require.NoError(t, err)
-		seenCommit := makeTestCommit(h, tmtime.Now())
+		seenCommit := makeTestExtCommit(h, tmtime.Now())
 		bs.SaveBlock(block, partSet, seenCommit)
 	}

@@ -452,7 +431,7 @@ func TestPruneBlocks(t *testing.T) {
 }

 func TestLoadBlockMeta(t *testing.T) {
-	bs, db := freshBlockStore()
+	bs, db := newInMemoryBlockStore()
 	height := int64(10)
 	loadMeta := func() (interface{}, error) {
 		meta := bs.LoadBlockMeta(height)
@@ -499,7 +478,7 @@ func TestBlockFetchAtHeight(t *testing.T) {

 	partSet, err := block.MakePartSet(2)
 	require.NoError(t, err)
-	seenCommit := makeTestCommit(10, tmtime.Now())
+	seenCommit := makeTestExtCommit(block.Header.Height, tmtime.Now())
 	bs.SaveBlock(block, partSet, seenCommit)
 	require.Equal(t, bs.Height(), block.Header.Height, "expecting the new height to be changed")

@@ -521,9 +500,12 @@ func TestBlockFetchAtHeight(t *testing.T) {
 }

 func TestSeenAndCanonicalCommit(t *testing.T) {
-	bs, _ := freshBlockStore()
+	state, store, cleanup, err := makeStateAndBlockStore(t.TempDir())
+	defer cleanup()
+	require.NoError(t, err)
+
 	loadCommit := func() (interface{}, error) {
-		meta := bs.LoadSeenCommit()
+		meta := store.LoadSeenCommit()
 		return meta, nil
 	}

@@ -536,19 +518,19 @@ func TestSeenAndCanonicalCommit(t *testing.T) {
 	// produce a few blocks and check that the correct seen and cannoncial commits
 	// are persisted.
 	for h := int64(3); h <= 5; h++ {
-		blockCommit := makeTestCommit(h-1, tmtime.Now())
+		blockCommit := makeTestExtCommit(h-1, tmtime.Now()).StripExtensions()
 		block := factory.MakeBlock(state, h, blockCommit)
 		partSet, err := block.MakePartSet(2)
 		require.NoError(t, err)
-		seenCommit := makeTestCommit(h, tmtime.Now())
-		bs.SaveBlock(block, partSet, seenCommit)
-		c3 := bs.LoadSeenCommit()
+		seenCommit := makeTestExtCommit(h, tmtime.Now())
+		store.SaveBlock(block, partSet, seenCommit)
+		c3 := store.LoadSeenCommit()
 		require.NotNil(t, c3)
 		require.Equal(t, h, c3.Height)
-		require.Equal(t, seenCommit.Hash(), c3.Hash())
-		c5 := bs.LoadBlockCommit(h)
+		require.Equal(t, seenCommit.StripExtensions().Hash(), c3.Hash())
+		c5 := store.LoadBlockCommit(h)
 		require.Nil(t, c5)
-		c6 := bs.LoadBlockCommit(h - 1)
+		c6 := store.LoadBlockCommit(h - 1)
 		require.Equal(t, blockCommit.Hash(), c6.Hash())
 	}

@@ -8,7 +8,7 @@ import (
 	"github.com/tendermint/tendermint/types"
 )

-func MakeCommit(ctx context.Context, blockID types.BlockID, height int64, round int32, voteSet *types.VoteSet, validators []types.PrivValidator, now time.Time) (*types.Commit, error) {
+func MakeExtendedCommit(ctx context.Context, blockID types.BlockID, height int64, round int32, voteSet *types.VoteSet, validators []types.PrivValidator, now time.Time) (*types.ExtendedCommit, error) {
 	// all sign
 	for i := 0; i < len(validators); i++ {
 		pubKey, err := validators[i].GetPubKey(ctx)
@@ -37,5 +37,5 @@ func MakeCommit(ctx context.Context, blockID types.BlockID, height int64, round
 		}
 	}

-	return voteSet.MakeCommit(), nil
+	return voteSet.MakeExtendedCommit(), nil
 }