Cache-wrap context during ante handler exec (#2781)

* Use cache-wrapped multi-store in ante
* Implement TestBaseAppAnteHandler
* Add reference documentation for BaseApp/CheckTx/DeliverTx

PENDING.md

@@ -53,9 +53,10 @@ IMPROVEMENTS
   * [\#2749](https://github.com/cosmos/cosmos-sdk/pull/2749) Add --chain-id flag to gaiad testnet
 
 * Gaia
- - #2773 Require moniker to be provided on `gaiad init`.
- - #2672 [Makefile] Updated for better Windows compatibility and ledger support logic, get_tools was rewritten as a cross-compatible Makefile.
- - [#110](https://github.com/tendermint/devops/issues/110) Updated CircleCI job to trigger website build when cosmos docs are updated.
+  - #2772 Update BaseApp to not persist state when the ante handler fails on DeliverTx.
+  - #2773 Require moniker to be provided on `gaiad init`.
+  - #2672 [Makefile] Updated for better Windows compatibility and ledger support logic, get_tools was rewritten as a cross-compatible Makefile.
+  - [#110](https://github.com/tendermint/devops/issues/110) Updated CircleCI job to trigger website build when cosmos docs are updated.
 
 * SDK
  - [x/mock/simulation] [\#2720] major cleanup, introduction of helper objects, reorganization

baseapp/baseapp.go

@@ -10,7 +10,6 @@ import (
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/crypto/tmhash"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
 
@@ -505,11 +504,11 @@ func validateBasicTxMsgs(msgs []sdk.Msg) sdk.Error {
 // retrieve the context for the ante handler and store the tx bytes; store
 // the vote infos if the tx runs within the deliverTx() state.
 func (app *BaseApp) getContextForAnte(mode runTxMode, txBytes []byte) (ctx sdk.Context) {
-	// Get the context
-	ctx = getState(app, mode).ctx.WithTxBytes(txBytes)
+	ctx = app.getState(mode).ctx.WithTxBytes(txBytes)
 	if mode == runTxModeDeliver {
 		ctx = ctx.WithVoteInfos(app.voteInfos)
 	}
+
 	return
 }
 
@@ -571,7 +570,7 @@ func (app *BaseApp) runMsgs(ctx sdk.Context, msgs []sdk.Msg, mode runTxMode) (re
 
 // Returns the applicantion's deliverState if app is in runTxModeDeliver,
 // otherwise it returns the application's checkstate.
-func getState(app *BaseApp, mode runTxMode) *state {
+func (app *BaseApp) getState(mode runTxMode) *state {
 	if mode == runTxModeCheck || mode == runTxModeSimulate {
 		return app.checkState
 	}
@@ -581,20 +580,42 @@ func getState(app *BaseApp, mode runTxMode) *state {
 
 func (app *BaseApp) initializeContext(ctx sdk.Context, mode runTxMode) sdk.Context {
 	if mode == runTxModeSimulate {
-		ctx = ctx.WithMultiStore(getState(app, runTxModeSimulate).CacheMultiStore())
+		ctx = ctx.WithMultiStore(app.getState(runTxModeSimulate).CacheMultiStore())
 	}
 	return ctx
 }
 
+// cacheTxContext returns a new context based off of the provided context with a
+// cache wrapped multi-store and the store itself to allow the caller to write
+// changes from the cached multi-store.
+func (app *BaseApp) cacheTxContext(
+	ctx sdk.Context, txBytes []byte, mode runTxMode,
+) (sdk.Context, sdk.CacheMultiStore) {
+
+	msCache := app.getState(mode).CacheMultiStore()
+	if msCache.TracingEnabled() {
+		msCache = msCache.WithTracingContext(
+			sdk.TraceContext(
+				map[string]interface{}{
+					"txHash": fmt.Sprintf("%X", tmhash.Sum(txBytes)),
+				},
+			),
+		).(sdk.CacheMultiStore)
+	}
+
+	return ctx.WithMultiStore(msCache), msCache
+}
+
 // runTx processes a transaction. The transactions is proccessed via an
-// anteHandler. txBytes may be nil in some cases, eg. in tests. Also, in the
-// future we may support "internal" transactions.
+// anteHandler. The provided txBytes may be nil in some cases, eg. in tests. For
+// further details on transaction execution, reference the BaseApp SDK
+// documentation.
 func (app *BaseApp) runTx(mode runTxMode, txBytes []byte, tx sdk.Tx) (result sdk.Result) {
 	// NOTE: GasWanted should be returned by the AnteHandler. GasUsed is
 	// determined by the GasMeter. We need access to the context to get the gas
 	// meter so we initialize upfront.
 	var gasWanted int64
-	var msCache sdk.CacheMultiStore
+
 	ctx := app.getContextForAnte(mode, txBytes)
 	ctx = app.initializeContext(ctx, mode)
 
@@ -619,16 +640,27 @@ func (app *BaseApp) runTx(mode runTxMode, txBytes []byte, tx sdk.Tx) (result sdk
 		return err.Result()
 	}
 
-	// run the ante handler
+	// Execute the ante handler if one is defined.
 	if app.anteHandler != nil {
-		newCtx, result, abort := app.anteHandler(ctx, tx, (mode == runTxModeSimulate))
+		var anteCtx sdk.Context
+		var msCache sdk.CacheMultiStore
+
+		// Cache wrap context before anteHandler call in case it aborts.
+		// This is required for both CheckTx and DeliverTx.
+		// https://github.com/cosmos/cosmos-sdk/issues/2772
+		// NOTE: Alternatively, we could require that anteHandler ensures that
+		// writes do not happen if aborted/failed.  This may have some
+		// performance benefits, but it'll be more difficult to get right.
+		anteCtx, msCache = app.cacheTxContext(ctx, txBytes, mode)
+
+		newCtx, result, abort := app.anteHandler(anteCtx, tx, (mode == runTxModeSimulate))
 		if abort {
 			return result
 		}
 		if !newCtx.IsZero() {
 			ctx = newCtx
 		}
-
+		msCache.Write()
 		gasWanted = result.GasWanted
 	}
 
@@ -638,17 +670,10 @@ func (app *BaseApp) runTx(mode runTxMode, txBytes []byte, tx sdk.Tx) (result sdk
 		return
 	}
 
-	// Keep the state in a transient CacheWrap in case processing the messages
-	// fails.
-	msCache = getState(app, mode).CacheMultiStore()
-	if msCache.TracingEnabled() {
-		msCache = msCache.WithTracingContext(sdk.TraceContext(
-			map[string]interface{}{"txHash": cmn.HexBytes(tmhash.Sum(txBytes)).String()},
-		)).(sdk.CacheMultiStore)
-	}
-
-	ctx = ctx.WithMultiStore(msCache)
-	result = app.runMsgs(ctx, msgs, mode)
+	// Create a new context based off of the existing context with a cache wrapped
+	// multi-store in case message processing fails.
+	runMsgCtx, msCache := app.cacheTxContext(ctx, txBytes, mode)
+	result = app.runMsgs(runMsgCtx, msgs, mode)
 	result.GasWanted = gasWanted
 
 	// only update state if all messages pass

baseapp/baseapp_test.go

@@ -282,8 +282,19 @@ func TestInitChainer(t *testing.T) {
 
 // Simple tx with a list of Msgs.
 type txTest struct {
-	Msgs    []sdk.Msg
-	Counter int64
+	Msgs       []sdk.Msg
+	Counter    int64
+	FailOnAnte bool
+}
+
+func (tx *txTest) setFailOnAnte(fail bool) {
+	tx.FailOnAnte = fail
+}
+
+func (tx *txTest) setFailOnHandler(fail bool) {
+	for i, msg := range tx.Msgs {
+		tx.Msgs[i] = msgCounter{msg.(msgCounter).Counter, fail}
+	}
 }
 
 // Implements Tx
@@ -297,7 +308,8 @@ const (
 // ValidateBasic() fails on negative counters.
 // Otherwise it's up to the handlers
 type msgCounter struct {
-	Counter int64
+	Counter       int64
+	FailOnHandler bool
 }
 
 // Implements Msg
@@ -315,9 +327,9 @@ func (msg msgCounter) ValidateBasic() sdk.Error {
 func newTxCounter(txInt int64, msgInts ...int64) *txTest {
 	var msgs []sdk.Msg
 	for _, msgInt := range msgInts {
-		msgs = append(msgs, msgCounter{msgInt})
+		msgs = append(msgs, msgCounter{msgInt, false})
 	}
-	return &txTest{msgs, txInt}
+	return &txTest{msgs, txInt, false}
 }
 
 // a msg we dont know how to route
@@ -369,8 +381,13 @@ func testTxDecoder(cdc *codec.Codec) sdk.TxDecoder {
 func anteHandlerTxTest(t *testing.T, capKey *sdk.KVStoreKey, storeKey []byte) sdk.AnteHandler {
 	return func(ctx sdk.Context, tx sdk.Tx, simulate bool) (newCtx sdk.Context, res sdk.Result, abort bool) {
 		store := ctx.KVStore(capKey)
-		msgCounter := tx.(txTest).Counter
-		res = incrementingCounter(t, store, storeKey, msgCounter)
+		txTest := tx.(txTest)
+
+		if txTest.FailOnAnte {
+			return newCtx, sdk.ErrInternal("ante handler failure").Result(), true
+		}
+
+		res = incrementingCounter(t, store, storeKey, txTest.Counter)
 		return
 	}
 }
@@ -381,10 +398,15 @@ func handlerMsgCounter(t *testing.T, capKey *sdk.KVStoreKey, deliverKey []byte)
 		var msgCount int64
 		switch m := msg.(type) {
 		case *msgCounter:
+			if m.FailOnHandler {
+				return sdk.ErrInternal("message handler failure").Result()
+			}
+
 			msgCount = m.Counter
 		case *msgCounter2:
 			msgCount = m.Counter
 		}
+
 		return incrementingCounter(t, store, deliverKey, msgCount)
 	}
 }
@@ -712,12 +734,12 @@ func TestRunInvalidTransaction(t *testing.T) {
 
 	// Transaction with no known route
 	{
-		unknownRouteTx := txTest{[]sdk.Msg{msgNoRoute{}}, 0}
+		unknownRouteTx := txTest{[]sdk.Msg{msgNoRoute{}}, 0, false}
 		err := app.Deliver(unknownRouteTx)
 		require.EqualValues(t, sdk.CodeUnknownRequest, err.Code)
 		require.EqualValues(t, sdk.CodespaceRoot, err.Codespace)
 
-		unknownRouteTx = txTest{[]sdk.Msg{msgCounter{}, msgNoRoute{}}, 0}
+		unknownRouteTx = txTest{[]sdk.Msg{msgCounter{}, msgNoRoute{}}, 0, false}
 		err = app.Deliver(unknownRouteTx)
 		require.EqualValues(t, sdk.CodeUnknownRequest, err.Code)
 		require.EqualValues(t, sdk.CodespaceRoot, err.Codespace)
@@ -829,3 +851,72 @@ func TestTxGasLimits(t *testing.T) {
 		}
 	}
 }
+
+func TestBaseAppAnteHandler(t *testing.T) {
+	anteKey := []byte("ante-key")
+	anteOpt := func(bapp *BaseApp) {
+		bapp.SetAnteHandler(anteHandlerTxTest(t, capKey1, anteKey))
+	}
+
+	deliverKey := []byte("deliver-key")
+	routerOpt := func(bapp *BaseApp) {
+		bapp.Router().AddRoute(routeMsgCounter, handlerMsgCounter(t, capKey1, deliverKey))
+	}
+
+	cdc := codec.New()
+	app := setupBaseApp(t, anteOpt, routerOpt)
+
+	app.InitChain(abci.RequestInitChain{})
+	registerTestCodec(cdc)
+	app.BeginBlock(abci.RequestBeginBlock{})
+
+	// execute a tx that will fail ante handler execution
+	//
+	// NOTE: State should not be mutated here. This will be implicitly checked by
+	// the next txs ante handler execution (anteHandlerTxTest).
+	tx := newTxCounter(0, 0)
+	tx.setFailOnAnte(true)
+	txBytes, err := cdc.MarshalBinaryLengthPrefixed(tx)
+	require.NoError(t, err)
+	res := app.DeliverTx(txBytes)
+	require.False(t, res.IsOK(), fmt.Sprintf("%v", res))
+
+	ctx := app.getState(runTxModeDeliver).ctx
+	store := ctx.KVStore(capKey1)
+	require.Equal(t, int64(0), getIntFromStore(store, anteKey))
+
+	// execute at tx that will pass the ante handler (the checkTx state should
+	// mutate) but will fail the message handler
+	tx = newTxCounter(0, 0)
+	tx.setFailOnHandler(true)
+
+	txBytes, err = cdc.MarshalBinaryLengthPrefixed(tx)
+	require.NoError(t, err)
+
+	res = app.DeliverTx(txBytes)
+	require.False(t, res.IsOK(), fmt.Sprintf("%v", res))
+
+	ctx = app.getState(runTxModeDeliver).ctx
+	store = ctx.KVStore(capKey1)
+	require.Equal(t, int64(1), getIntFromStore(store, anteKey))
+	require.Equal(t, int64(0), getIntFromStore(store, deliverKey))
+
+	// execute a successful ante handler and message execution where state is
+	// implicitly checked by previous tx executions
+	tx = newTxCounter(1, 0)
+
+	txBytes, err = cdc.MarshalBinaryLengthPrefixed(tx)
+	require.NoError(t, err)
+
+	res = app.DeliverTx(txBytes)
+	require.True(t, res.IsOK(), fmt.Sprintf("%v", res))
+
+	ctx = app.getState(runTxModeDeliver).ctx
+	store = ctx.KVStore(capKey1)
+	require.Equal(t, int64(2), getIntFromStore(store, anteKey))
+	require.Equal(t, int64(1), getIntFromStore(store, deliverKey))
+
+	// commit
+	app.EndBlock(abci.RequestEndBlock{})
+	app.Commit()
+}

cmd/gaia/cli_test/cli_test.go

@@ -537,16 +537,20 @@ func TestGaiaCLISendGenerateSignAndBroadcast(t *testing.T) {
 	success, stdout, _ = executeWriteRetStdStreams(t, fmt.Sprintf(
 		"gaiacli tx broadcast %v --json %v", flags, signedTxFile.Name()))
 	require.True(t, success)
+
 	var result struct {
 		Response abci.ResponseDeliverTx
 	}
+
 	require.Nil(t, app.MakeCodec().UnmarshalJSON([]byte(stdout), &result))
 	require.Equal(t, msg.Fee.Gas, result.Response.GasUsed)
 	require.Equal(t, msg.Fee.Gas, result.Response.GasWanted)
+
 	tests.WaitForNextNBlocksTM(2, port)
 
 	barAcc := executeGetAccount(t, fmt.Sprintf("gaiacli query account %s %v", barAddr, flags))
 	require.Equal(t, int64(10), barAcc.GetCoins().AmountOf(stakeTypes.DefaultBondDenom).Int64())
+
 	fooAcc = executeGetAccount(t, fmt.Sprintf("gaiacli query account %s %v", fooAddr, flags))
 	require.Equal(t, int64(40), fooAcc.GetCoins().AmountOf(stakeTypes.DefaultBondDenom).Int64())
 }