From 8120a86eaa01d34de9ef314a69efa9c9c3a78430 Mon Sep 17 00:00:00 2001
From: Devon Bear <itsdevbear@berachain.com>
Date: Thu, 25 Jan 2024 12:01:48 -0500
Subject: [PATCH] fix(ve): Ensure that sdk side ve math matches `cometbft`
 (#19200)

---
 CHANGELOG.md          |  1 +
 baseapp/abci_test.go  | 17 ++++++++++++++++-
 baseapp/abci_utils.go | 22 ++++++++++------------
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 81ebd9dd02..8b7dff6def 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -88,6 +88,7 @@ Every module contains its own CHANGELOG.md. Please refer to the module you are i
 * (simulation) [#17911](https://github.com/cosmos/cosmos-sdk/pull/17911) Fix all problems with executing command `make test-sim-custom-genesis-fast` for simulation test.
 * (simulation) [#18196](https://github.com/cosmos/cosmos-sdk/pull/18196) Fix the problem of `validator set is empty after InitGenesis` in simulation test.
 * (baseapp) [#18551](https://github.com/cosmos/cosmos-sdk/pull/18551) Fix SelectTxForProposal the calculation method of tx bytes size is inconsistent with CometBFT
+* (abci): [#19200](https://github.com/cosmos/cosmos-sdk/pull/19200) Ensure that sdk side ve math matches cometbft
 
 ### API Breaking Changes
 
diff --git a/baseapp/abci_test.go b/baseapp/abci_test.go
index efca5b7407..769349f84e 100644
--- a/baseapp/abci_test.go
+++ b/baseapp/abci_test.go
@@ -2224,11 +2224,25 @@ func TestBaseApp_VoteExtensions(t *testing.T) {
 	}
 	require.Equal(t, 10, successful)
 
+	extVotes := []abci.ExtendedVoteInfo{}
+	for _, val := range vals {
+		extVotes = append(extVotes, abci.ExtendedVoteInfo{
+			VoteExtension:      allVEs[0],
+			BlockIdFlag:        cmtproto.BlockIDFlagCommit,
+			ExtensionSignature: []byte{},
+			Validator: abci.Validator{
+				Address: val.Bytes(),
+				Power:   666,
+			},
+		},
+		)
+	}
+
 	prepPropReq := &abci.RequestPrepareProposal{
 		Height: 1,
 		LocalLastCommit: abci.ExtendedCommitInfo{
 			Round: 0,
-			Votes: []abci.ExtendedVoteInfo{},
+			Votes: extVotes,
 		},
 	}
 
@@ -2287,6 +2301,7 @@ func TestBaseApp_VoteExtensions(t *testing.T) {
 			ExtensionSignature: extSig,
 			Validator: abci.Validator{
 				Address: vals[i].Bytes(),
+				Power:   666,
 			},
 		})
 	}
diff --git a/baseapp/abci_utils.go b/baseapp/abci_utils.go
index 53fb89db5a..1c42411d2e 100644
--- a/baseapp/abci_utils.go
+++ b/baseapp/abci_utils.go
@@ -14,17 +14,10 @@ import (
 	protoio "github.com/cosmos/gogoproto/io"
 	"github.com/cosmos/gogoproto/proto"
 
-	"cosmossdk.io/math"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/mempool"
 )
 
-// VoteExtensionThreshold defines the total voting power % that must be
-// submitted in order for all vote extensions to be considered valid for a
-// given height.
-var VoteExtensionThreshold = math.LegacyNewDecWithPrec(667, 3)
-
 type (
 	// ValidatorStore defines the interface contract require for verifying vote
 	// extension signatures. Typically, this will be implemented by the x/staking
@@ -133,13 +126,18 @@ func ValidateVoteExtensions(
 		sumVP += vote.Validator.Power
 	}
 
-	if totalVP > 0 {
-		percentSubmitted := math.LegacyNewDecFromInt(math.NewInt(sumVP)).Quo(math.LegacyNewDecFromInt(math.NewInt(totalVP)))
-		if percentSubmitted.LT(VoteExtensionThreshold) {
-			return fmt.Errorf("insufficient cumulative voting power received to verify vote extensions; got: %s, expected: >=%s", percentSubmitted, VoteExtensionThreshold)
-		}
+	// This check is probably unnecessary, but better safe than sorry.
+	if totalVP <= 0 {
+		return fmt.Errorf("total voting power must be positive, got: %d", totalVP)
 	}
 
+	// If the sum of the voting power has not reached (2/3 + 1) we need to error.
+	if requiredVP := ((totalVP * 2) / 3) + 1; sumVP < requiredVP {
+		return fmt.Errorf(
+			"insufficient cumulative voting power received to verify vote extensions; got: %d, expected: >=%d",
+			sumVP, requiredVP,
+		)
+	}
 	return nil
 }