feat: support executing sub-calls with a different gas limit

CHANGELOG.md

@@ -55,6 +55,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (server) [#24720](https://github.com/cosmos/cosmos-sdk/pull/24720) add `verbose_log_level` flag for configuring the log level when switching to verbose logging mode during sensitive operations (such as chain upgrades).
 * (crypto) [#24861](https://github.com/cosmos/cosmos-sdk/pull/24861) add `PubKeyFromCometTypeAndBytes` helper function to convert from `comet/v2` PubKeys to the `cryptotypes.Pubkey` interface.
 * (abci_utils) [#25008](https://github.com/cosmos/cosmos-sdk/pull/25008) add the ability to assign a custom signer extraction adapter in `DefaultProposalHandler`.
+* (context) [#25303](https://github.com/cosmos/cosmos-sdk/pull/25303) Add `WithGasRemaining` to execute sub-calls with a specific gas limit.
 
 ### Improvements
 

store/CHANGELOG.md

@@ -29,6 +29,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * [#20425](https://github.com/cosmos/cosmos-sdk/pull/20425) Fix nil pointer panic when querying historical state where a new store does not exist.
 
+### Features
+
+* [#25303](https://github.com/cosmos/cosmos-sdk/pull/25303) Implement ProxyGasMeter to execute sub-calls with a different gas limit.
+
 ## v1.1.2 (March 31, 2025)
 
 ### Bug Fixes

store/types/proxygasmeter.go

@@ -0,0 +1,46 @@
+package types
+
+import "fmt"
+
+var _ GasMeter = &ProxyGasMeter{}
+
+// ProxyGasMeter is like a basicGasMeter, but delegates the gas changes (refund and consume) to the parent GasMeter in
+// realtime, ensuring accurate gas accounting even during panics.
+type ProxyGasMeter struct {
+	GasMeter
+
+	parent GasMeter
+}
+
+// NewProxyGasMeter creates a ProxyGasMeter that wraps a parent gas meter, inheriting the minimum of the new limit and the parent's remaining gas.
+// It delegates consumption to the parent in real time, ensuring accurate gas accounting even during panics.
+//
+// Returns the parent directly if the new limit is greater than or equal to its remaining gas.
+func NewProxyGasMeter(gasMeter GasMeter, limit Gas) GasMeter {
+	limit = min(limit, gasMeter.GasRemaining())
+	return &ProxyGasMeter{
+		GasMeter: NewGasMeter(limit),
+		parent:   gasMeter,
+	}
+}
+
+// RefundGas will also refund gas to parent gas meter.
+func (pgm ProxyGasMeter) RefundGas(amount Gas, descriptor string) {
+	pgm.parent.RefundGas(amount, descriptor)
+	pgm.GasMeter.RefundGas(amount, descriptor)
+}
+
+// ConsumeGas will also consume gas from parent gas meter.
+//
+// it consume sub-gasmeter first, which means if sub-gasmeter runs out of gas,
+// the gas is not charged in parent gas meter, the assumption for business logic
+// is the gas is always charged before the work is done, so when out-of-gas panic happens,
+// the actual work is not done yet, so we don't need to consume the gas in parent gas meter.
+func (pgm ProxyGasMeter) ConsumeGas(amount Gas, descriptor string) {
+	pgm.parent.ConsumeGas(amount, descriptor)
+	pgm.GasMeter.ConsumeGas(amount, descriptor)
+}
+
+func (pgm ProxyGasMeter) String() string {
+	return fmt.Sprintf("ProxyGasMeter{consumed: %d, limit: %d}", pgm.GasConsumed(), pgm.Limit())
+}

store/types/proxygasmeter_test.go

@@ -0,0 +1,45 @@
+package types
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestProxyGasMeter(t *testing.T) {
+	baseGas := uint64(1000)
+	limit := uint64(300)
+
+	bgm := NewGasMeter(baseGas)
+	pgm := NewProxyGasMeter(bgm, limit)
+
+	require.Equal(t, Gas(0), pgm.GasConsumed())
+	require.Equal(t, limit, pgm.Limit())
+	require.Equal(t, limit, pgm.GasRemaining())
+
+	pgm.ConsumeGas(100, "test")
+	require.Equal(t, Gas(100), pgm.GasConsumed())
+	require.Equal(t, Gas(100), bgm.GasConsumed())
+	require.Equal(t, limit-100, pgm.GasRemaining())
+	require.False(t, pgm.IsOutOfGas())
+	require.False(t, pgm.IsPastLimit())
+
+	pgm.ConsumeGas(200, "test")
+	require.Equal(t, Gas(300), pgm.GasConsumed())
+	require.Equal(t, Gas(300), bgm.GasConsumed())
+	require.Equal(t, Gas(0), pgm.GasRemaining())
+	require.Equal(t, Gas(700), bgm.GasRemaining())
+	require.True(t, pgm.IsOutOfGas())
+	require.False(t, pgm.IsPastLimit())
+
+	require.Panics(t, func() {
+		pgm.ConsumeGas(1, "test")
+	})
+	require.Equal(t, Gas(699), bgm.GasRemaining())
+
+	pgm.RefundGas(1, "test")
+	require.Equal(t, Gas(300), pgm.GasConsumed())
+	require.Equal(t, Gas(0), pgm.GasRemaining())
+	require.True(t, pgm.IsOutOfGas())
+	require.False(t, pgm.IsPastLimit())
+}

types/context.go

@@ -224,6 +224,15 @@ func (c Context) WithGasMeter(meter storetypes.GasMeter) Context {
 	return c
 }
 
+// WithGasLimit replaces the GasMeter with a ProxyGasMeter whose gas limit is set to the minimal of the
+// given limit and the remaining gas in the current GasMeter.
+//
+// ProxyGasMeter will delegate the gas consumption to the parent gas meter in realtime, so there's no need to write
+// back the gas consumed to the parent gas meter when the sub-GasMeter is done.
+func (c Context) WithGasLimit(limit storetypes.Gas) Context {
+	return c.WithGasMeter(storetypes.NewProxyGasMeter(c.GasMeter(), limit))
+}
+
 // WithBlockGasMeter returns a Context with an updated block GasMeter
 func (c Context) WithBlockGasMeter(meter storetypes.GasMeter) Context {
 	c.blockGasMeter = meter

types/context_test.go

@@ -241,3 +241,52 @@ func (s *contextTestSuite) TestUnwrapSDKContext() {
 	sdkCtx2 = types.UnwrapSDKContext(ctx)
 	s.Require().Equal(sdkCtx, sdkCtx2)
 }
+
+func (s *contextTestSuite) TestProxyGasMeter() {
+	ctx := types.NewContext(nil, cmtproto.Header{}, false, nil).WithGasMeter(storetypes.NewGasMeter(20))
+	s.Require().EqualValues(20, ctx.GasMeter().Limit())
+
+	ctx.GasMeter().ConsumeGas(5, "test")
+	s.Require().EqualValues(5, ctx.GasMeter().GasConsumed())
+	s.Require().EqualValues(15, ctx.GasMeter().GasRemaining())
+
+	{
+		ctx := ctx.WithGasLimit(10)
+		s.Require().EqualValues(10, ctx.GasMeter().Limit())
+
+		ctx.GasMeter().ConsumeGas(5, "test")
+		s.Require().EqualValues(5, ctx.GasMeter().GasConsumed())
+
+		s.Require().Panics(func() {
+			ctx.GasMeter().ConsumeGas(6, "test")
+		})
+		s.Require().EqualValues(11, ctx.GasMeter().GasConsumed())
+	}
+
+	s.Require().EqualValues(10, ctx.GasMeter().GasConsumed())
+	s.Require().EqualValues(10, ctx.GasMeter().GasRemaining())
+
+	{
+		ctx := ctx.WithGasLimit(5)
+		s.Require().EqualValues(5, ctx.GasMeter().Limit())
+
+		s.Require().Panics(func() {
+			ctx.GasMeter().ConsumeGas(6, "test")
+		})
+		s.Require().EqualValues(6, ctx.GasMeter().GasConsumed())
+	}
+
+	s.Require().EqualValues(10, ctx.GasMeter().GasConsumed())
+	s.Require().EqualValues(10, ctx.GasMeter().GasRemaining())
+
+	{
+		ctx := ctx.WithGasLimit(15)
+		s.Require().EqualValues(10, ctx.GasMeter().Limit())
+
+		ctx.GasMeter().ConsumeGas(10, "test")
+		s.Require().EqualValues(10, ctx.GasMeter().GasConsumed())
+	}
+
+	s.Require().EqualValues(20, ctx.GasMeter().GasConsumed())
+	s.Require().EqualValues(0, ctx.GasMeter().GasRemaining())
+}