Refactor DeliverTx hook so that panics can be handled (#543)

## Describe your changes and provide context
Panics in tx handler is usually handled by a defer statement containing
a `recover()` clause. Previously the call stack looks like:
```
func DeliverTx:
    func runTx:
        deferred recover
        (actual processing)
    DeliverTx hook
```
In the above structure, DeliverTx hooks are run on `DeliverTx` level, so
they are outside the deferred recover clause which is within `runTx`
level.

This PR changes it to be:
```
func DeliverTx:
    func runTx:
        deferred recover
        (actual processing)
        DeliverTx hook
```
so that the hook can be recovered as well

## Testing performed to validate your change
unit test

baseapp/abci.go

@@ -328,9 +328,6 @@ func (app *BaseApp) DeliverTx(ctx sdk.Context, req abci.RequestDeliverTx, tx sdk
 			return
 		}
 	}
-	for _, hook := range app.deliverTxHooks {
-		hook(ctx, tx, checksum, res)
-	}
 	return
 }
 

baseapp/baseapp.go

@@ -76,7 +76,7 @@ type (
 	// (or removed a substore) between two versions of the software.
 	StoreLoader func(ms sdk.CommitMultiStore) error
 
-	DeliverTxHook func(sdk.Context, sdk.Tx, [32]byte, abci.ResponseDeliverTx)
+	DeliverTxHook func(sdk.Context, sdk.Tx, [32]byte, sdk.DeliverTxHookInput)
 )
 
 // BaseApp reflects the ABCI application implementation.
@@ -1007,6 +1007,25 @@ func (app *BaseApp) runTx(ctx sdk.Context, mode runTxMode, tx sdk.Tx, checksum [
 	if ctx.CheckTxCallback() != nil {
 		ctx.CheckTxCallback()(ctx, err)
 	}
+	var evmTxInfo *abci.EvmTxInfo
+	if ctx.IsEVM() {
+		evmTxInfo = &abci.EvmTxInfo{
+			SenderAddress: ctx.EVMSenderAddress(),
+			Nonce:         ctx.EVMNonce(),
+			TxHash:        ctx.EVMTxHash(),
+			VmError:       result.EvmError,
+		}
+	}
+	var events []abci.Event = []abci.Event{}
+	if result != nil {
+		events = sdk.MarkEventsToIndex(result.Events, app.indexEvents)
+	}
+	for _, hook := range app.deliverTxHooks {
+		hook(ctx, tx, checksum, sdk.DeliverTxHookInput{
+			EvmTxInfo: evmTxInfo,
+			Events:    events,
+		})
+	}
 	return gInfo, result, anteEvents, priority, pendingTxChecker, expireHandler, ctx, err
 }
 

baseapp/deliver_tx_test.go

@@ -1646,6 +1646,48 @@ func TestDeliverTx(t *testing.T) {
 	}
 }
 
+func TestDeliverTxHooks(t *testing.T) {
+	anteOpt := func(*BaseApp) {}
+	routerOpt := func(bapp *BaseApp) {
+		r := sdk.NewRoute(routeMsgCounter, func(ctx sdk.Context, msg sdk.Msg) (*sdk.Result, error) { return &sdk.Result{}, nil })
+		bapp.Router().AddRoute(r)
+	}
+
+	app := setupBaseApp(t, anteOpt, routerOpt)
+	app.InitChain(context.Background(), &abci.RequestInitChain{})
+
+	// Create same codec used in txDecoder
+	codec := codec.NewLegacyAmino()
+	registerTestCodec(codec)
+
+	header := tmproto.Header{Height: 1}
+	app.setDeliverState(header)
+	app.BeginBlock(app.deliverState.ctx, abci.RequestBeginBlock{Header: header})
+
+	// every even i is an evm tx
+	counter := int64(1)
+	tx := newTxCounter(counter, counter)
+
+	txBytes, err := codec.Marshal(tx)
+	require.NoError(t, err)
+
+	decoded, _ := app.txDecoder(txBytes)
+
+	ctx := app.deliverState.ctx
+
+	// register noop hook
+	app.RegisterDeliverTxHook(func(ctx sdk.Context, tx sdk.Tx, b [32]byte, rdt sdk.DeliverTxHookInput) {})
+	res := app.DeliverTx(ctx, abci.RequestDeliverTx{Tx: txBytes}, decoded, sha256.Sum256(txBytes))
+	require.True(t, res.IsOK(), fmt.Sprintf("%v", res))
+
+	// register panic hook (should be captured by recover() middleware)
+	app.RegisterDeliverTxHook(func(ctx sdk.Context, tx sdk.Tx, b [32]byte, rdt sdk.DeliverTxHookInput) { panic(1) })
+	require.NotPanics(t, func() {
+		res = app.DeliverTx(ctx, abci.RequestDeliverTx{Tx: txBytes}, decoded, sha256.Sum256(txBytes))
+	})
+	require.False(t, res.IsOK(), fmt.Sprintf("%v", res))
+}
+
 func TestOptionFunction(t *testing.T) {
 	logger := defaultLogger()
 	db := dbm.NewMemDB()

types/result.go

@@ -263,3 +263,8 @@ func WrapServiceResult(ctx Context, res proto.Message, err error) (*Result, erro
 	}
 	return sdkRes, nil
 }
+
+type DeliverTxHookInput struct {
+	EvmTxInfo *abci.EvmTxInfo
+	Events    []abci.Event
+}