refactor: Revert middlewares to antehandlers (part 1/2: baseapp) (#11979)

## Description

We decided to remove middlewares, and revert to antehandlers (exactly like in v045) for this release. A better middleware solution will be implemented after v046.

ref: #11955 

Because this refactor is big, so I decided to cut it into two. This PR is part 1 of 2:
- part 1: Revert baseapp and middlewares to v0.45.4
- part 2: Add posthandler, tips, priority

---
 Suggestion for reviewers:

This PR might still be hard to review though. I think it's easier to actually review the diff between v0.45.4 and this PR:
- `git difftool -d v0.45.4..am/revert-045-baseapp baseapp`
  - most important parts to review: runTx, runMsgs
- `git difftool -d v0.45.4..am/revert-045-baseapp x/auth/ante`
  - only cosmetic changes
- `git difftool -d v0.45.4..am/revert-045-baseapp simapp`



---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/main/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/main/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/main/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

server/mock/app.go

@@ -6,36 +6,22 @@ import (
 	"fmt"
 	"path/filepath"
 
+	"github.com/tendermint/tendermint/types"
+
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/libs/log"
-	"github.com/tendermint/tendermint/types"
-	dbm "github.com/tendermint/tm-db"
 
 	bam "github.com/cosmos/cosmos-sdk/baseapp"
 	"github.com/cosmos/cosmos-sdk/codec"
-	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
-	"github.com/cosmos/cosmos-sdk/simapp"
 	storetypes "github.com/cosmos/cosmos-sdk/store/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
-	"github.com/cosmos/cosmos-sdk/types/tx"
-	"github.com/cosmos/cosmos-sdk/x/auth/middleware"
 )
 
-func testTxHandler(options middleware.TxHandlerOptions) tx.Handler {
-	return middleware.ComposeMiddlewares(
-		middleware.NewRunMsgsTxHandler(options.MsgServiceRouter, options.LegacyRouter),
-		middleware.NewTxDecoderMiddleware(options.TxDecoder),
-		middleware.GasTxMiddleware,
-		middleware.RecoveryTxMiddleware,
-		middleware.NewIndexEventsTxMiddleware(options.IndexEvents),
-	)
-}
-
 // NewApp creates a simple mock kvstore app for testing. It should work
 // similar to a real app. Make sure rootDir is empty before running the test,
 // in order to guarantee consistent results
 func NewApp(rootDir string, logger log.Logger) (abci.Application, error) {
-	db, err := dbm.NewDB("mock", dbm.MemDBBackend, filepath.Join(rootDir, "data"))
+	db, err := sdk.NewLevelDB("mock", filepath.Join(rootDir, "data"))
 	if err != nil {
 		return nil, err
 	}
@@ -44,7 +30,7 @@ func NewApp(rootDir string, logger log.Logger) (abci.Application, error) {
 	capKeyMainStore := sdk.NewKVStoreKey("main")
 
 	// Create BaseApp.
-	baseApp := bam.NewBaseApp("kvstore", logger, db)
+	baseApp := bam.NewBaseApp("kvstore", logger, db, decodeTx)
 
 	// Set mounts for BaseApp's MultiStore.
 	baseApp.MountStores(capKeyMainStore)
@@ -52,19 +38,7 @@ func NewApp(rootDir string, logger log.Logger) (abci.Application, error) {
 	baseApp.SetInitChainer(InitChainer(capKeyMainStore))
 
 	// Set a Route.
-	encCfg := simapp.MakeTestEncodingConfig()
-	legacyRouter := middleware.NewLegacyRouter()
-	// We're adding a test legacy route here, which accesses the kvstore
-	// and simply sets the Msg's key/value pair in the kvstore.
-	legacyRouter.AddRoute(sdk.NewRoute("kvstore", KVStoreHandler(capKeyMainStore)))
-	txHandler := testTxHandler(
-		middleware.TxHandlerOptions{
-			LegacyRouter:     legacyRouter,
-			MsgServiceRouter: middleware.NewMsgServiceRouter(encCfg.InterfaceRegistry),
-			TxDecoder:        decodeTx,
-		},
-	)
-	baseApp.SetTxHandler(txHandler)
+	baseApp.Router().AddRoute(sdk.NewRoute("kvstore", KVStoreHandler(capKeyMainStore)))
 
 	// Load latest version.
 	if err := baseApp.LoadLatestVersion(); err != nil {
@@ -78,7 +52,7 @@ func NewApp(rootDir string, logger log.Logger) (abci.Application, error) {
 // them to the db
 func KVStoreHandler(storeKey storetypes.StoreKey) sdk.Handler {
 	return func(ctx sdk.Context, msg sdk.Msg) (*sdk.Result, error) {
-		dTx, ok := msg.(*kvstoreTx)
+		dTx, ok := msg.(kvstoreTx)
 		if !ok {
 			return nil, errors.New("KVStoreHandler should only receive kvstoreTx")
 		}
@@ -90,14 +64,8 @@ func KVStoreHandler(storeKey storetypes.StoreKey) sdk.Handler {
 		store := ctx.KVStore(storeKey)
 		store.Set(key, value)
 
-		any, err := codectypes.NewAnyWithValue(msg)
-		if err != nil {
-			return nil, err
-		}
-
 		return &sdk.Result{
-			Log:          fmt.Sprintf("set %s=%s", key, value),
-			MsgResponses: []*codectypes.Any{any},
+			Log: fmt.Sprintf("set %s=%s", key, value),
 		}, nil
 	}
 }

server/mock/tx.go

@@ -4,16 +4,12 @@ package mock
 import (
 	"bytes"
 	"fmt"
-	"math"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	"github.com/cosmos/cosmos-sdk/x/auth/middleware"
 )
 
-// kvstoreTx defines a tx for mock purposes. The `key` and `value` fields will
-// set those bytes in the kvstore, and the `bytes` field represents its
-// GetSignBytes value.
+// An sdk.Tx which is its own sdk.Msg.
 type kvstoreTx struct {
 	key   []byte
 	value []byte
@@ -21,15 +17,12 @@ type kvstoreTx struct {
 }
 
 // dummy implementation of proto.Message
-func (msg *kvstoreTx) Reset()         {}
-func (msg *kvstoreTx) String() string { return "TODO" }
-func (msg *kvstoreTx) ProtoMessage()  {}
+func (msg kvstoreTx) Reset()         {}
+func (msg kvstoreTx) String() string { return "TODO" }
+func (msg kvstoreTx) ProtoMessage()  {}
 
-var (
-	_ sdk.Tx           = &kvstoreTx{}
-	_ sdk.Msg          = &kvstoreTx{}
-	_ middleware.GasTx = &kvstoreTx{}
-)
+var _ sdk.Tx = kvstoreTx{}
+var _ sdk.Msg = kvstoreTx{}
 
 func NewTx(key, value string) kvstoreTx {
 	bytes := fmt.Sprintf("%s=%s", key, value)
@@ -48,7 +41,7 @@ func (tx kvstoreTx) Type() string {
 	return "kvstore_tx"
 }
 
-func (tx *kvstoreTx) GetMsgs() []sdk.Msg {
+func (tx kvstoreTx) GetMsgs() []sdk.Msg {
 	return []sdk.Msg{tx}
 }
 
@@ -69,10 +62,6 @@ func (tx kvstoreTx) GetSigners() []sdk.AccAddress {
 	return nil
 }
 
-func (tx kvstoreTx) GetGas() uint64 {
-	return math.MaxUint64
-}
-
 // takes raw transaction bytes and decodes them into an sdk.Tx. An sdk.Tx has
 // all the signatures and can be used to authenticate.
 func decodeTx(txBytes []byte) (sdk.Tx, error) {
@@ -81,10 +70,10 @@ func decodeTx(txBytes []byte) (sdk.Tx, error) {
 	split := bytes.Split(txBytes, []byte("="))
 	if len(split) == 1 {
 		k := split[0]
-		tx = &kvstoreTx{k, k, txBytes}
+		tx = kvstoreTx{k, k, txBytes}
 	} else if len(split) == 2 {
 		k, v := split[0], split[1]
-		tx = &kvstoreTx{k, v, txBytes}
+		tx = kvstoreTx{k, v, txBytes}
 	} else {
 		return nil, sdkerrors.Wrap(sdkerrors.ErrTxDecode, "too many '='")
 	}