R4R: fix Iterator leak, see #2105

PENDING.md

@@ -70,6 +70,7 @@ BUG FIXES
 * Gaia
 
 * SDK
-    *  \#1988 Make us compile on OpenBSD (disable ledger) [#1988] (https://github.com/cosmos/cosmos-sdk/issues/1988)
+    * \#1988 Make us compile on OpenBSD (disable ledger) [#1988] (https://github.com/cosmos/cosmos-sdk/issues/1988)
+    * \#2105 Fix DB Iterator leak, which may leak a go routine.
 
 * Tendermint

examples/democoin/x/assoc/validator_set.go

@@ -93,6 +93,7 @@ func (valset ValidatorSet) Dissociate(ctx sdk.Context, base sdk.AccAddress, asso
 func (valset ValidatorSet) Associations(ctx sdk.Context, base sdk.AccAddress) (res []sdk.AccAddress) {
 	res = make([]sdk.AccAddress, valset.maxAssoc)
 	iter := sdk.KVStorePrefixIterator(valset.store, GetAssocPrefix(base))
+	defer iter.Close()
 	i := 0
 	for ; iter.Valid(); iter.Next() {
 		key := iter.Key()

examples/democoin/x/oracle/handler.go

@@ -28,6 +28,7 @@ func (keeper Keeper) update(ctx sdk.Context, val sdk.Validator, valset sdk.Valid
 		prefix := GetSignPrefix(p, keeper.cdc)
 		store := ctx.KVStore(keeper.key)
 		iter := sdk.KVStorePrefixIterator(store, prefix)
+		defer iter.Close()
 		for ; iter.Valid(); iter.Next() {
 			if valset.Validator(ctx, iter.Value()) != nil {
 				store.Delete(iter.Key())

store/iavlstore_test.go

@@ -168,6 +168,7 @@ func TestIAVLSubspaceIterator(t *testing.T) {
 		require.EqualValues(t, value, expectedKey)
 		i++
 	}
+	iter.Close()
 	require.Equal(t, len(expected), i)
 
 	iter = sdk.KVStorePrefixIterator(iavlStore, []byte{byte(55), byte(255), byte(255)})
@@ -183,6 +184,7 @@ func TestIAVLSubspaceIterator(t *testing.T) {
 		require.EqualValues(t, value, []byte("test4"))
 		i++
 	}
+	iter.Close()
 	require.Equal(t, len(expected), i)
 
 	iter = sdk.KVStorePrefixIterator(iavlStore, []byte{byte(255), byte(255)})
@@ -198,6 +200,7 @@ func TestIAVLSubspaceIterator(t *testing.T) {
 		require.EqualValues(t, value, []byte("test4"))
 		i++
 	}
+	iter.Close()
 	require.Equal(t, len(expected), i)
 }
 

x/auth/mapper.go

@@ -87,6 +87,7 @@ func (am AccountMapper) SetAccount(ctx sdk.Context, acc Account) {
 func (am AccountMapper) IterateAccounts(ctx sdk.Context, process func(Account) (stop bool)) {
 	store := ctx.KVStore(am.key)
 	iter := sdk.KVStorePrefixIterator(store, []byte("account:"))
+	defer iter.Close()
 	for {
 		if !iter.Valid() {
 			return

x/gov/keeper_test.go

@@ -130,6 +130,7 @@ func TestDeposits(t *testing.T) {
 	require.Equal(t, fourSteak, deposit.Amount)
 	depositsIterator.Next()
 	require.False(t, depositsIterator.Valid())
+	depositsIterator.Close()
 
 	// Test Refund Deposits
 	deposit, found = keeper.GetDeposit(ctx, proposalID, addrs[1])
@@ -196,6 +197,7 @@ func TestVotes(t *testing.T) {
 	require.Equal(t, OptionNoWithVeto, vote.Option)
 	votesIterator.Next()
 	require.False(t, votesIterator.Valid())
+	votesIterator.Close()
 }
 
 func TestProposalQueues(t *testing.T) {

x/gov/tally.go

@@ -36,6 +36,7 @@ func tally(ctx sdk.Context, keeper Keeper, proposal Proposal) (passes bool, tall
 
 	// iterate over all the votes
 	votesIterator := keeper.GetVotes(ctx, proposal.GetProposalID())
+	defer votesIterator.Close()
 	for ; votesIterator.Valid(); votesIterator.Next() {
 		vote := &Vote{}
 		keeper.cdc.MustUnmarshalBinary(votesIterator.Value(), vote)
@@ -64,7 +65,6 @@ func tally(ctx sdk.Context, keeper Keeper, proposal Proposal) (passes bool, tall
 
 		keeper.deleteVote(ctx, vote.ProposalID, vote.Voter)
 	}
-	votesIterator.Close()
 
 	// Iterate over the validators again to tally their voting power and see who didn't vote
 	nonVoting = []sdk.AccAddress{}