fix: isolate CheckTx and simulation state from DeliverTx commits

CHANGELOG.md

@@ -36,6 +36,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
+## Unreleased
+
+### Bug Fixes
+
+* (baseapp) [#25529](https://github.com/cosmos/cosmos-sdk/pull/25529) isolate CheckTx and simulation state from DeliverTx commits by loading the last committed snapshot and keeping the simulation context in sync.
+
 ## [v0.53.4](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.53.3) - 2025-07-25
 
 This patch update also includes minor dependency bumps.

baseapp/state/manager.go

@@ -24,6 +24,9 @@ type Manager struct {
 	// - checkState: Used for CheckTx, which is set based on the previous block's
 	// state. This state is never committed.
 	//
+	// - simulationState: Mirrors the last committed state for simulations. It shares
+	// the same root snapshot as CheckTx but is never written back.
+	//
 	// - prepareProposalState: Used for PrepareProposal, which is set based on the
 	// previous block's state. This state is never committed. In case of multiple
 	// consensus rounds, the state is always reset to the previous block's state.
@@ -35,6 +38,7 @@ type Manager struct {
 	// - finalizeBlockState: Used for FinalizeBlock, which is set based on the
 	// previous block's state. This state is committed.
 	checkState           *State
+	simulationState      *State
 	prepareProposalState *State
 	processProposalState *State
 	finalizeBlockState   *State
@@ -63,6 +67,15 @@ func (mgr *Manager) GetState(mode sdk.ExecMode) *State {
 	case sdk.ExecModeProcessProposal:
 		return mgr.processProposalState
 
+	case sdk.ExecModeSimulate:
+		// Keep the simulation context aligned with the CheckTx context while
+		// preserving its own store branch.
+		if mgr.checkState != nil && mgr.simulationState != nil {
+			mgr.simulationState.SetContext(mgr.checkState.Context().WithMultiStore(mgr.simulationState.MultiStore))
+		}
+
+		return mgr.simulationState
+
 	default:
 		return mgr.checkState
 	}
@@ -79,6 +92,20 @@ func (mgr *Manager) SetState(
 	streamingManager storetypes.StreamingManager,
 ) {
 	ms := unbranchedStore.CacheMultiStore()
+	if mode == sdk.ExecModeCheck {
+		// Load the last committed version so CheckTx (and by extension simulations)
+		// operate on the same state that DeliverTx committed in the previous block.
+		// Ref: https://github.com/cosmos/cosmos-sdk/issues/20685
+		//
+		// Using the versioned cache also unwraps any inter-block cache layers,
+		// preventing simulation runs from polluting the global inter-block cache
+		// with transient writes.
+		// Ref: https://github.com/cosmos/cosmos-sdk/issues/23891
+		if versionedCache, err := unbranchedStore.CacheMultiStoreWithVersion(h.Height); err == nil {
+			ms = versionedCache
+		}
+	}
+
 	headerInfo := header.Info{
 		Height:  h.Height,
 		Time:    h.Time,
@@ -97,8 +124,14 @@ func (mgr *Manager) SetState(
 
 	switch mode {
 	case sdk.ExecModeCheck:
-		baseState.SetContext(baseState.Context().WithIsCheckTx(true).WithMinGasPrices(mgr.gasConfig.MinGasPrices))
-		mgr.checkState = baseState
+		// Simulations never persist state, so they can reuse the base snapshot
+		// that was branched off the last committed height.
+		mgr.simulationState = baseState
+
+		// Branch again for CheckTx so AnteHandler writes do not leak back into
+		// the shared simulation snapshot.
+		checkMs := ms.CacheMultiStore()
+		mgr.checkState = NewState(baseState.Context().WithIsCheckTx(true).WithMinGasPrices(mgr.gasConfig.MinGasPrices).WithMultiStore(checkMs), checkMs)
 
 	case sdk.ExecModePrepareProposal:
 		mgr.prepareProposalState = baseState
@@ -121,6 +154,7 @@ func (mgr *Manager) ClearState(mode sdk.ExecMode) {
 	switch mode {
 	case sdk.ExecModeCheck:
 		mgr.checkState = nil
+		mgr.simulationState = nil
 
 	case sdk.ExecModePrepareProposal:
 		mgr.prepareProposalState = nil

store/cachemulti/store.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"maps"
+	"sync"
 
 	"cosmossdk.io/store/tracekv"
 	"cosmossdk.io/store/types"
@@ -21,7 +22,10 @@ const storeNameCtxKey = "store_name"
 // NOTE: a Store (and MultiStores in general) should never expose the
 // keys for the substores.
 type Store struct {
-	stores map[types.StoreKey]types.CacheWrap
+	// storesMut ensures concurrent callers (e.g. ExportGenesisForModules goroutines)
+	// don't race when lazily creating substores.
+	storesMut *sync.RWMutex
+	stores    map[types.StoreKey]types.CacheWrap
 
 	traceWriter  io.Writer
 	traceContext types.TraceContext
@@ -38,6 +42,7 @@ func NewFromKVStore(
 	traceWriter io.Writer, traceContext types.TraceContext,
 ) Store {
 	cms := Store{
+		storesMut:    &sync.RWMutex{},
 		stores:       make(map[types.StoreKey]types.CacheWrap, len(stores)),
 		traceWriter:  traceWriter,
 		traceContext: traceContext,
@@ -66,6 +71,7 @@ func NewFromParent(
 	traceWriter io.Writer, traceContext types.TraceContext,
 ) Store {
 	return Store{
+		storesMut:    &sync.RWMutex{},
 		stores:       make(map[types.StoreKey]types.CacheWrap),
 		traceWriter:  traceWriter,
 		traceContext: traceContext,
@@ -126,7 +132,12 @@ func (cms Store) GetStoreType() types.StoreType {
 
 // Write calls Write on each underlying store.
 func (cms Store) Write() {
-	for _, store := range cms.stores {
+	cms.storesMut.RLock()
+	stores := make(map[types.StoreKey]types.CacheWrap, len(cms.stores))
+	maps.Copy(stores, cms.stores)
+	cms.storesMut.RUnlock()
+
+	for _, store := range stores {
 		store.Write()
 	}
 }
@@ -157,6 +168,9 @@ func (cms Store) CacheMultiStoreWithVersion(_ int64) (types.CacheMultiStore, err
 }
 
 func (cms Store) getCacheWrapper(key types.StoreKey) types.CacheWrapper {
+	cms.storesMut.Lock()
+	defer cms.storesMut.Unlock()
+
 	store, ok := cms.stores[key]
 	if !ok && cms.parentStore != nil {
 		// load on demand

store/cachemulti/store_test.go

@@ -2,6 +2,7 @@ package cachemulti
 
 import (
 	"fmt"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -12,7 +13,7 @@ import (
 func TestStoreGetKVStore(t *testing.T) {
 	require := require.New(t)
 
-	s := Store{stores: map[types.StoreKey]types.CacheWrap{}}
+	s := Store{storesMut: &sync.RWMutex{}, stores: map[types.StoreKey]types.CacheWrap{}}
 	key := types.NewKVStoreKey("abc")
 	errMsg := fmt.Sprintf("kv store with key %v has not been registered in stores", key)
 

tests/go.mod

@@ -239,6 +239,7 @@ require (
 replace (
 	// We always want to test against the latest version of the simapp.
 	cosmossdk.io/simapp => ../simapp
+	cosmossdk.io/store => ../store
 	github.com/99designs/keyring => github.com/cosmos/keyring v1.2.0
 	// We always want to test against the latest version of the SDK.
 	github.com/cosmos/cosmos-sdk => ../.

tests/go.sum

@@ -40,8 +40,6 @@ cosmossdk.io/math v1.5.3 h1:WH6tu6Z3AUCeHbeOSHg2mt9rnoiUWVWaQ2t6Gkll96U=
 cosmossdk.io/math v1.5.3/go.mod h1:uqcZv7vexnhMFJF+6zh9EWdm/+Ylyln34IvPnBauPCQ=
 cosmossdk.io/schema v1.1.0 h1:mmpuz3dzouCoyjjcMcA/xHBEmMChN+EHh8EHxHRHhzE=
 cosmossdk.io/schema v1.1.0/go.mod h1:Gb7pqO+tpR+jLW5qDcNOSv0KtppYs7881kfzakguhhI=
-cosmossdk.io/store v1.3.0-beta.0 h1:jwJvAQkMsCY9xJHU/nz7yOo1WnNRvcI/9yLRSgZoFTk=
-cosmossdk.io/store v1.3.0-beta.0/go.mod h1:CMz9JQGEA8eRcZv2pK07NgEbL4NEb9wVgzWK4tNQaPg=
 cosmossdk.io/x/tx v0.14.0 h1:hB3O25kIcyDW/7kMTLMaO8Ripj3yqs5imceVd6c/heA=
 cosmossdk.io/x/tx v0.14.0/go.mod h1:Tn30rSRA1PRfdGB3Yz55W4Sn6EIutr9xtMKSHij+9PM=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=