fix: Inconsistent limit on InfiniteGasMeter and add GasLeft func to GasMeter

CHANGELOG.md

@@ -75,6 +75,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Bug Fixes
 
+* [\#9651](https://github.com/cosmos/cosmos-sdk/pull/9651) Change inconsistent limit of `0` to `MaxUint64` on InfiniteGasMeter and add GasRemaining func to GasMeter.
 * [\#9639](https://github.com/cosmos/cosmos-sdk/pull/9639) Check store keys length before accessing them by making sure that `key` is of length `m+1` (for `key[n:m]`)
 * (types) [\#9627](https://github.com/cosmos/cosmos-sdk/pull/9627) Fix nil pointer panic on `NewBigIntFromInt`
 * (x/genutil) [\#9574](https://github.com/cosmos/cosmos-sdk/pull/9575) Actually use the `gentx` client tx flags (like `--keyring-dir`)

store/types/gas.go

@@ -41,6 +41,7 @@ type ErrorGasOverflow struct {
 type GasMeter interface {
 	GasConsumed() Gas
 	GasConsumedToLimit() Gas
+	GasRemaining() Gas
 	Limit() Gas
 	ConsumeGas(amount Gas, descriptor string)
 	RefundGas(amount Gas, descriptor string)
@@ -66,6 +67,13 @@ func (g *basicGasMeter) GasConsumed() Gas {
 	return g.consumed
 }
 
+func (g *basicGasMeter) GasRemaining() Gas {
+	if g.IsPastLimit() {
+		return 0
+	}
+	return g.limit - g.consumed
+}
+
 func (g *basicGasMeter) Limit() Gas {
 	return g.limit
 }
@@ -145,8 +153,12 @@ func (g *infiniteGasMeter) GasConsumedToLimit() Gas {
 	return g.consumed
 }
 
+func (g *infiniteGasMeter) GasRemaining() Gas {
+	return math.MaxUint64
+}
+
 func (g *infiniteGasMeter) Limit() Gas {
-	return 0
+	return math.MaxUint64
 }
 
 func (g *infiniteGasMeter) ConsumeGas(amount Gas, descriptor string) {

store/types/gas_test.go

@@ -10,13 +10,16 @@ import (
 func TestInfiniteGasMeter(t *testing.T) {
 	t.Parallel()
 	meter := NewInfiniteGasMeter()
-	require.Equal(t, uint64(0), meter.Limit())
+	require.Equal(t, uint64(math.MaxUint64), meter.Limit())
+	require.Equal(t, uint64(math.MaxUint64), meter.GasRemaining())
 	require.Equal(t, uint64(0), meter.GasConsumed())
 	require.Equal(t, uint64(0), meter.GasConsumedToLimit())
 	meter.ConsumeGas(10, "consume 10")
+	require.Equal(t, uint64(math.MaxUint64), meter.GasRemaining())
 	require.Equal(t, uint64(10), meter.GasConsumed())
 	require.Equal(t, uint64(10), meter.GasConsumedToLimit())
 	meter.RefundGas(1, "refund 1")
+	require.Equal(t, uint64(math.MaxUint64), meter.GasRemaining())
 	require.Equal(t, uint64(9), meter.GasConsumed())
 	require.False(t, meter.IsPastLimit())
 	require.False(t, meter.IsOutOfGas())
@@ -48,6 +51,7 @@ func TestGasMeter(t *testing.T) {
 			used += usage
 			require.NotPanics(t, func() { meter.ConsumeGas(usage, "") }, "Not exceeded limit but panicked. tc #%d, usage #%d", tcnum, unum)
 			require.Equal(t, used, meter.GasConsumed(), "Gas consumption not match. tc #%d, usage #%d", tcnum, unum)
+			require.Equal(t, tc.limit-used, meter.GasRemaining(), "Gas left not match. tc #%d, usage #%d", tcnum, unum)
 			require.Equal(t, used, meter.GasConsumedToLimit(), "Gas consumption (to limit) not match. tc #%d, usage #%d", tcnum, unum)
 			require.False(t, meter.IsPastLimit(), "Not exceeded limit but got IsPastLimit() true")
 			if unum < len(tc.usage)-1 {
@@ -60,13 +64,20 @@ func TestGasMeter(t *testing.T) {
 		require.Panics(t, func() { meter.ConsumeGas(1, "") }, "Exceeded but not panicked. tc #%d", tcnum)
 		require.Equal(t, meter.GasConsumedToLimit(), meter.Limit(), "Gas consumption (to limit) not match limit")
 		require.Equal(t, meter.GasConsumed(), meter.Limit()+1, "Gas consumption not match limit+1")
+		require.Equal(t, uint64(0), meter.GasRemaining())
 
 		require.NotPanics(t, func() { meter.RefundGas(1, "refund 1") })
-		require.Equal(t, meter.GasConsumed(), meter.Limit(), "Gas consumption not match limit+1")
+		require.Equal(t, meter.GasConsumed(), meter.Limit(), "Gas consumption not match with limit")
+		require.Equal(t, uint64(0), meter.GasRemaining())
 		require.Panics(t, func() { meter.RefundGas(meter.GasConsumed()+1, "refund greater than consumed") })
 
+		require.NotPanics(t, func() { meter.RefundGas(meter.GasConsumed(), "refund consumed gas") })
+		require.Equal(t, meter.Limit(), meter.GasRemaining())
+
 		meter2 := NewGasMeter(math.MaxUint64)
+		require.Equal(t, uint64(math.MaxUint64), meter2.GasRemaining())
 		meter2.ConsumeGas(Gas(math.MaxUint64/2), "consume half max uint64")
+		require.Equal(t, Gas(math.MaxUint64-(math.MaxUint64/2)), meter2.GasRemaining())
 		require.Panics(t, func() { meter2.ConsumeGas(Gas(math.MaxUint64/2)+2, "panic") })
 	}
 }

x/auth/ante/setup_test.go

@@ -1,6 +1,8 @@
 package ante_test
 
 import (
+	"math"
+
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	"github.com/cosmos/cosmos-sdk/testutil/testdata"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -33,8 +35,8 @@ func (suite *AnteTestSuite) TestSetup() {
 	// Set height to non-zero value for GasMeter to be set
 	suite.ctx = suite.ctx.WithBlockHeight(1)
 
-	// Context GasMeter Limit not set
-	suite.Require().Equal(uint64(0), suite.ctx.GasMeter().Limit(), "GasMeter set with limit before setup")
+	// Context GasMeter Limit set to MaxUint64
+	suite.Require().Equal(uint64(math.MaxUint64), suite.ctx.GasMeter().Limit(), "GasMeter set with limit other than MaxUint64 before setup")
 
 	newCtx, err := antehandler(suite.ctx, tx, false)
 	suite.Require().Nil(err, "SetUpContextDecorator returned error")