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

- It's a common pattern to execute a sub-call with a lower gas limit than
the whole tx gas limit, this PR introduce a primitive method in `Context` for that use case.

Author: HuangYi

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) [#]() 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
+
+* [#]() 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 +1,69 @@
+package types
+
+import (
+	fmt "fmt"
+)
+
+var _ GasMeter = &ProxyGasMeter{}
+
+// ProxyGasMeter wraps another GasMeter, but enforces a lower gas limit.
+// Gas consumption is delegated to the wrapped GasMeter, so it won't risk losing gas accounting compared to standalone
+// gas meter.
+type ProxyGasMeter struct {
+	GasMeter
+
+	limit Gas
+}
+
+// NewProxyGasMeter returns a new GasMeter which wraps the provided gas meter.
+// The remaining is the maximum gas that can be consumed on top of current consumed
+// gas of the wrapped gas meter.
+//
+// If the new remaining is greater than or equal to the existing remaining gas, no wrapping is needed
+// and the original gas meter is returned.
+func NewProxyGasMeter(gasMeter GasMeter, remaining Gas) GasMeter {
+	if remaining >= gasMeter.GasRemaining() {
+		return gasMeter
+	}
+
+	return &ProxyGasMeter{
+		GasMeter: gasMeter,
+		limit:    remaining + gasMeter.GasConsumed(),
+	}
+}
+
+func (pgm ProxyGasMeter) GasRemaining() Gas {
+	if pgm.IsPastLimit() {
+		return 0
+	}
+	return pgm.limit - pgm.GasConsumed()
+}
+
+func (pgm ProxyGasMeter) Limit() Gas {
+	return pgm.limit
+}
+
+func (pgm ProxyGasMeter) IsPastLimit() bool {
+	return pgm.GasConsumed() > pgm.limit
+}
+
+func (pgm ProxyGasMeter) IsOutOfGas() bool {
+	return pgm.GasConsumed() >= pgm.limit
+}
+
+func (pgm ProxyGasMeter) ConsumeGas(amount Gas, descriptor string) {
+	consumed, overflow := addUint64Overflow(pgm.GasMeter.GasConsumed(), amount)
+	if overflow {
+		panic(ErrorGasOverflow{Descriptor: descriptor})
+	}
+
+	if consumed > pgm.limit {
+		panic(ErrorOutOfGas{Descriptor: 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 +1,83 @@
+package types
+
+import (
+	math "math"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestProxyGasMeterBasic(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(700), bgm.GasRemaining())
+
+	pgm.RefundGas(1, "test")
+	require.Equal(t, Gas(299), pgm.GasConsumed())
+	require.Equal(t, Gas(1), pgm.GasRemaining())
+	require.False(t, pgm.IsOutOfGas())
+	require.False(t, pgm.IsPastLimit())
+}
+
+func TestProxyGasMeterInfinit(t *testing.T) {
+	limit := uint64(300)
+
+	bgm := NewInfiniteGasMeter()
+	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(math.MaxUint64), bgm.GasRemaining())
+	require.True(t, pgm.IsOutOfGas())
+	require.False(t, pgm.IsPastLimit())
+
+	require.Panics(t, func() {
+		pgm.ConsumeGas(1, "test")
+	})
+	require.Equal(t, Gas(math.MaxUint64), bgm.GasRemaining())
+
+	pgm.RefundGas(1, "test")
+	require.Equal(t, Gas(299), pgm.GasConsumed())
+	require.Equal(t, Gas(1), pgm.GasRemaining())
+	require.False(t, pgm.IsOutOfGas())
+	require.False(t, pgm.IsPastLimit())
+}

types/context.go

@@ -224,6 +224,14 @@ func (c Context) WithGasMeter(meter storetypes.GasMeter) Context {
 	return c
 }
 
+// WithGasRemaining returns a Context with a lower remaining gas,
+// it's used to execute sub-calls with a lower gas limit.
+// the gas consumption is still tracked by the parent gas meter in realtime,
+// there's no risk of losing gas accounting.
+func (c Context) WithGasRemaining(remaining storetypes.Gas) Context {
+	return c.WithGasMeter(storetypes.NewProxyGasMeter(c.GasMeter(), remaining))
+}
+
 // WithBlockGasMeter returns a Context with an updated block GasMeter
 func (c Context) WithBlockGasMeter(meter storetypes.GasMeter) Context {
 	c.blockGasMeter = meter