fix(baseapp): ensure finalize block response is not empty (backport #23879) (#23902)

Co-authored-by: mmsqe <mavis@crypto.com>
Co-authored-by: aljo242 <alex@interchainlabs.io>

CHANGELOG.md

@@ -51,6 +51,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Bug Fixes
 
+* (baseapp) [#23879](https://github.com/cosmos/cosmos-sdk/pull/23879) Ensure finalize block response is not empty in the defer check of FinalizeBlock to avoid panic by nil pointer.
 * (query) [#23883](https://github.com/cosmos/cosmos-sdk/pull/23883) Fix NPE in query pagination.
 * (client) [#23860](https://github.com/cosmos/cosmos-sdk/pull/23860) Add missing `unordered` field for legacy amino signing of tx body.
 * (x/bank) [#23836](https://github.com/cosmos/cosmos-sdk/pull/23836) Fix `DenomMetadata` rpc allow value with slashes.

baseapp/abci.go

@@ -855,6 +855,9 @@ func (app *BaseApp) internalFinalizeBlock(ctx context.Context, req *abci.Request
 // where they adhere to the sdk.Tx interface.
 func (app *BaseApp) FinalizeBlock(req *abci.RequestFinalizeBlock) (res *abci.ResponseFinalizeBlock, err error) {
 	defer func() {
+		if res == nil {
+			return
+		}
 		// call the streaming service hooks with the FinalizeBlock messages
 		for _, streamingListener := range app.streamingManager.ABCIListeners {
 			if err := streamingListener.ListenFinalizeBlock(app.finalizeBlockState.Context(), *req, *res); err != nil {

baseapp/abci_test.go

@@ -43,6 +43,18 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
 
+type mockABCIListener struct {
+	ListenCommitFn func(context.Context, abci.ResponseCommit, []*storetypes.StoreKVPair) error
+}
+
+func (m mockABCIListener) ListenFinalizeBlock(_ context.Context, _ abci.RequestFinalizeBlock, _ abci.ResponseFinalizeBlock) error {
+	return nil
+}
+
+func (m *mockABCIListener) ListenCommit(ctx context.Context, commit abci.ResponseCommit, pairs []*storetypes.StoreKVPair) error {
+	return m.ListenCommitFn(ctx, commit, pairs)
+}
+
 func TestABCI_Info(t *testing.T) {
 	suite := NewBaseAppSuite(t)
 
@@ -2493,3 +2505,18 @@ func TestABCI_Proposal_FailReCheckTx(t *testing.T) {
 	require.NotEmpty(t, res.TxResults[0].Events)
 	require.True(t, res.TxResults[0].IsOK(), fmt.Sprintf("%v", res))
 }
+
+func TestFinalizeBlockDeferResponseHandle(t *testing.T) {
+	suite := NewBaseAppSuite(t, baseapp.SetHaltHeight(1))
+	suite.baseApp.SetStreamingManager(storetypes.StreamingManager{
+		ABCIListeners: []storetypes.ABCIListener{
+			&mockABCIListener{},
+		},
+	})
+
+	res, err := suite.baseApp.FinalizeBlock(&abci.RequestFinalizeBlock{
+		Height: 2,
+	})
+	require.Empty(t, res)
+	require.NotEmpty(t, err)
+}

x/evidence/README.md

@@ -219,11 +219,7 @@ The Cosmos SDK handles two types of evidence inside the ABCI `BeginBlock`:
 The evidence module handles these two evidence types the same way. First, the Cosmos SDK converts the CometBFT concrete evidence type to an SDK `Evidence` interface using `Equivocation` as the concrete type.
 
 ```protobuf reference
-<<<<<<< HEAD
-https://github.com/cosmos/cosmos-sdk/blob/v0.47.0-rc1/proto/cosmos/evidence/v1beta1/evidence.proto#L12-L32
-=======
 https://github.com/cosmos/cosmos-sdk/tree/release/v0.50.x/proto/cosmos/evidence/v1beta1/evidence.proto#L12-L32
->>>>>>> 5411e73bb (docs: update version references (#23898))
 ```
 
 For some `Equivocation` submitted in `block` to be valid, it must satisfy:
@@ -247,11 +243,7 @@ validator to ever re-enter the validator set.
 The `Equivocation` evidence is handled as follows:
 
 ```go reference
-<<<<<<< HEAD
-https://github.com/cosmos/cosmos-sdk/blob/v0.47.0-rc1/x/evidence/keeper/infraction.go#L26-L140
-=======
 https://github.com/cosmos/cosmos-sdk/tree/release/v0.50.x/x/evidence/keeper/infraction.go#L26-L140
->>>>>>> 5411e73bb (docs: update version references (#23898))
 ```
 
 **Note:** The slashing, jailing, and tombstoning calls are delegated through the `x/slashing` module