fix(gov): Fix v3 votes migrations (backport #14214) (#14277)

Co-authored-by: Amaury <1293565+amaurym@users.noreply.github.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

CHANGELOG.md

@@ -52,6 +52,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### State Machine Breaking
 
+* (x/gov) [#14214](https://github.com/cosmos/cosmos-sdk/pull/14214) Fix gov v0.46 migration to v1 votes.
+  * Also provide a helper function `govv046.Migrate_V0466_To_V0467` for migrating a chain already on v0.46 with versions <=v0.46.6 to the latest v0.46.7 correct state.
 * (x/group) [#14071](https://github.com/cosmos/cosmos-sdk/pull/14071) Don't re-tally proposal after voting period end if they have been marked as ACCEPTED or REJECTED.
 
 ### API Breaking Changes

RELEASE_NOTES.md

@@ -6,6 +6,10 @@ Please read the release notes of [v0.46.5](https://github.com/cosmos/cosmos-sdk/
 
 A critical vulnerability has been fixed in the group module. For safety, `v0.46.5` and `v0.46.6` are retracted, even though chains not using the group module are not affected. When using the group module, please upgrade immediately to `v0.46.7`.
 
+An issue has been discovered in the gov module's votes migration. It does not impact proposals and votes tallying, but the gRPC queries on votes are incorrect. This issue is fixed in `v0.46.7`, however:
+- if your chain is already on v0.46 using `<= v0.46.6`, a **coordinated upgrade** to v0.46.7 is required. You can use the helper function `govv046.Migrate_V046_6_To_V046_7` for migrating a chain **already on v0.46 with versions <=v0.46.6** to the latest v0.46.7 correct state.
+- if your chain is on a previous version <= v0.45, then simply use v0.46.7 when upgrading to v0.46.
+
 **NOTE**: The changes mentioned in `v0.46.3` are no longer required. The following replace directive can be removed from the chains.
 
 ```go

go.mod

@@ -168,8 +168,7 @@ replace (
 )
 
 retract (
-	// subject to a bug in the group module,
-	// these versions are safe to use when not using the group module
+	// subject to a bug in the group module and gov module migration
 	[v0.46.5, v0.46.6]
 	// subject to the dragonberry vulnerability
 	// and/or the bank coin metadata migration issue

x/gov/migrations/v046/json_test.go

@@ -19,6 +19,8 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/gov/types/v1beta1"
 )
 
+var voter = sdk.MustAccAddressFromBech32("cosmos1fl48vsnmsdzcv85q5d2q4z5ajdha8yu34mf0eh")
+
 func TestMigrateJSON(t *testing.T) {
 	encodingConfig := simapp.MakeTestEncodingConfig()
 	clientCtx := client.Context{}.

x/gov/migrations/v046/store.go

@@ -6,7 +6,8 @@ import (
 	storetypes "github.com/cosmos/cosmos-sdk/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	v042 "github.com/cosmos/cosmos-sdk/x/gov/migrations/v042"
-	"github.com/cosmos/cosmos-sdk/x/gov/types/v1beta1"
+	govv1 "github.com/cosmos/cosmos-sdk/x/gov/types/v1"
+	govv1beta1 "github.com/cosmos/cosmos-sdk/x/gov/types/v1beta1"
 )
 
 // migrateProposals migrates all legacy proposals into MsgExecLegacyContent
@@ -18,7 +19,7 @@ func migrateProposals(store sdk.KVStore, cdc codec.BinaryCodec) error {
 	defer iter.Close()
 
 	for ; iter.Valid(); iter.Next() {
-		var oldProp v1beta1.Proposal
+		var oldProp govv1beta1.Proposal
 		err := cdc.Unmarshal(iter.Value(), &oldProp)
 		if err != nil {
 			return err
@@ -40,12 +41,69 @@ func migrateProposals(store sdk.KVStore, cdc codec.BinaryCodec) error {
 	return nil
 }
 
-// MigrateStore performs in-place store migrations from v0.43 to v0.46. The
+// migrateVotes migrates all v1beta1 weighted votes (with sdk.Dec as weight)
+// to v1 weighted votes (with string as weight)
+func migrateVotes(store sdk.KVStore, cdc codec.BinaryCodec) error {
+	votesStore := prefix.NewStore(store, v042.VotesKeyPrefix)
+
+	iter := votesStore.Iterator(nil, nil)
+	defer iter.Close()
+
+	for ; iter.Valid(); iter.Next() {
+		var oldVote govv1beta1.Vote
+		err := cdc.Unmarshal(iter.Value(), &oldVote)
+		if err != nil {
+			return err
+		}
+
+		newVote := govv1.Vote{
+			ProposalId: oldVote.ProposalId,
+			Voter:      oldVote.Voter,
+		}
+		newOptions := make([]*govv1.WeightedVoteOption, len(oldVote.Options))
+		for i, o := range oldVote.Options {
+			newOptions[i] = &govv1.WeightedVoteOption{
+				Option: govv1.VoteOption(o.Option),
+				Weight: o.Weight.String(), // Convert to decimal string
+			}
+		}
+		newVote.Options = newOptions
+		bz, err := cdc.Marshal(&newVote)
+		if err != nil {
+			return err
+		}
+
+		// Set new value on store.
+		votesStore.Set(iter.Key(), bz)
+	}
+
+	return nil
+}
+
+// MigrateStore performs in-place store migrations from v2 (v0.43) to v3 (v0.46). The
 // migration includes:
 //
 // - Migrate proposals to be Msg-based.
 func MigrateStore(ctx sdk.Context, storeKey storetypes.StoreKey, cdc codec.BinaryCodec) error {
 	store := ctx.KVStore(storeKey)
 
+	if err := migrateVotes(store, cdc); err != nil {
+		return err
+	}
+
 	return migrateProposals(store, cdc)
 }
+
+// Migrate_V046_4_To_V046_5 is a helper function to migrate chains from <=v0.46.6
+// to v0.46.7 ONLY.
+//
+// IMPORTANT: Please do not use this function if you are upgrading to v0.46
+// from <=v0.45.
+//
+// This function migrates the store in-place by fixing the gov votes weight to
+// be stored as decimals strings (instead of the sdk.Dec BigInt representation).
+//
+// The store is expected to be the gov store, and not any prefixed substore.
+func Migrate_V046_6_To_V046_7(store sdk.KVStore, cdc codec.BinaryCodec) error {
+	return migrateVotes(store, cdc)
+}

x/gov/migrations/v046/store_test.go

@@ -39,6 +39,15 @@ func TestMigrateStore(t *testing.T) {
 	store.Set(v042gov.ProposalKey(prop1.ProposalId), prop1Bz)
 	store.Set(v042gov.ProposalKey(prop2.ProposalId), prop2Bz)
 
+	// Vote on prop 1
+	options := []v1beta1.WeightedVoteOption{
+		{Option: v1beta1.OptionNo, Weight: sdk.MustNewDecFromStr("0.3")},
+		{Option: v1beta1.OptionYes, Weight: sdk.MustNewDecFromStr("0.7")},
+	}
+	vote1 := v1beta1.NewVote(1, voter, options)
+	vote1Bz := cdc.MustMarshal(&vote1)
+	store.Set(v042gov.VoteKey(1, voter), vote1Bz)
+
 	// Run migrations.
 	err = v046gov.MigrateStore(ctx, govKey, cdc)
 	require.NoError(t, err)
@@ -52,6 +61,14 @@ func TestMigrateStore(t *testing.T) {
 	err = cdc.Unmarshal(store.Get(v042gov.ProposalKey(prop2.ProposalId)), &newProp2)
 	require.NoError(t, err)
 	compareProps(t, prop2, newProp2)
+
+	var newVote1 v1.Vote
+	err = cdc.Unmarshal(store.Get(v042gov.VoteKey(prop1.ProposalId, voter)), &newVote1)
+	require.NoError(t, err)
+	// Without the votes migration, we would have 300000000000000000 in state,
+	// because of how sdk.Dec stores itself in state.
+	require.Equal(t, "0.300000000000000000", newVote1.Options[0].Weight)
+	require.Equal(t, "0.700000000000000000", newVote1.Options[1].Weight)
 }
 
 func compareProps(t *testing.T, oldProp v1beta1.Proposal, newProp v1.Proposal) {