fix: Charge gas even when there are no entries in gaskv (backport cos…

…mos#10218) (cosmos#10696)

* fix: Charge gas even when there are no entries in gaskv (cosmos#10218)

<!--
The default pull request template is for types feat, fix, or refactor.
For other templates, add one of the following parameters to the url:
- template=docs.md
- template=other.md
-->

## Description

Closes: cosmos#10127

Charge gas for seeks with empty ranges

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

(cherry picked from commit 4c3aa4d)

# Conflicts:
#	CHANGELOG.md

* Fix conflicts

Co-authored-by: likhita-809 <78951027+likhita-809@users.noreply.github.com>
Co-authored-by: Amaury M <1293565+amaurym@users.noreply.github.com>

CHANGELOG.md

@@ -38,6 +38,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## [Unreleased]
 
+## [v0.45.0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.45.0) - 2021-12-07
+
+### State Machine Breaking
+
+* (store) [#10218](https://github.com/cosmos/cosmos-sdk/pull/10218) Charge gas even when there are no entries while seeking.
+
 ## [v0.44.5](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.44.5) - 2021-12-02
 
 ### Improvements

store/gaskv/store.go

@@ -166,10 +166,8 @@ func (gi *gasIterator) Error() error {
 // based on the current value's length.
 func (gi *gasIterator) consumeSeekGas() {
 	if gi.Valid() {
-		key := gi.Key()
 		value := gi.Value()
 
-		gi.gasMeter.ConsumeGas(gi.gasConfig.ReadCostPerByte*types.Gas(len(key)), types.GasValuePerByteDesc)
 		gi.gasMeter.ConsumeGas(gi.gasConfig.ReadCostPerByte*types.Gas(len(value)), types.GasValuePerByteDesc)
 	}
 	gi.gasMeter.ConsumeGas(gi.gasConfig.IterNextCostFlat, types.GasIterNextCostFlatDesc)

store/gaskv/store_test.go

@@ -5,11 +5,11 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+	dbm "github.com/tendermint/tm-db"
 
-	coretesting "cosmossdk.io/core/testing"
-	"cosmossdk.io/store/dbadapter"
-	"cosmossdk.io/store/gaskv"
-	"cosmossdk.io/store/types"
+	"github.com/cosmos/cosmos-sdk/store/dbadapter"
+	"github.com/cosmos/cosmos-sdk/store/gaskv"
+	"github.com/cosmos/cosmos-sdk/store/types"
 )
 
 func bz(s string) []byte { return []byte(s) }
@@ -38,7 +38,7 @@ func TestGasKVStoreBasic(t *testing.T) {
 }
 
 func TestGasKVStoreIterator(t *testing.T) {
-	mem := dbadapter.Store{DB: coretesting.NewMemDB()}
+	mem := dbadapter.Store{DB: dbm.NewMemDB()}
 	meter := types.NewGasMeter(100000)
 	st := gaskv.NewStore(mem, meter, types.KVGasConfig())
 	require.False(t, st.Has(keyFmt(1)))
@@ -73,16 +73,16 @@ func TestGasKVStoreIterator(t *testing.T) {
 	vb := iterator.Value()
 	require.Equal(t, vb, valFmt(2))
 	iterator.Next()
-	require.Equal(t, types.Gas(14565), meter.GasConsumed())
+	require.Equal(t, types.Gas(13377), meter.GasConsumed())
 	kc := iterator.Key()
 	require.Equal(t, kc, keyFmt(3))
 	vc := iterator.Value()
 	require.Equal(t, vc, valFmt(0))
 	iterator.Next()
-	require.Equal(t, types.Gas(14667), meter.GasConsumed())
+	require.Equal(t, types.Gas(13446), meter.GasConsumed())
 	require.False(t, iterator.Valid())
 	require.Panics(t, iterator.Next)
-	require.Equal(t, types.Gas(14697), meter.GasConsumed())
+	require.Equal(t, types.Gas(13476), meter.GasConsumed())
 	require.NoError(t, iterator.Error())
 
 	reverseIterator := st.ReverseIterator(nil, nil)
@@ -99,7 +99,8 @@ func TestGasKVStoreIterator(t *testing.T) {
 	reverseIterator.Next()
 	require.False(t, reverseIterator.Valid())
 	require.Panics(t, reverseIterator.Next)
-	require.Equal(t, types.Gas(15135), meter.GasConsumed())
+
+	require.Equal(t, types.Gas(13782), meter.GasConsumed())
 }
 
 func TestGasKVStoreOutOfGasSet(t *testing.T) {