feat: enforce app creator returning application implement AppWithPendingTxStream in build time (#440)

* feat: enforce app creator returning application implementing AppWithPendingTxStream in build time

* update application interface and app creator wiring for EVM server integration
* use cosmosevmserver.Application interface instead of servertypes.Application with assertion
* add new Application interface and AppCreator type to support pending tx stream

* add doc

Author: mmsqe

CHANGELOG.md

@@ -46,6 +46,7 @@
 - [\#301](https://github.com/cosmos/evm/pull/301) Add 4-node localnet infrastructure for testing multi-validator setups
 - [\#304](https://github.com/cosmos/evm/pull/304) Add system test framework for integration testing
 - [\#344](https://github.com/cosmos/evm/pull/344) Add txpool RPC namespace stubs in preparation for app-side mempool implementation
+- [\#440](https://github.com/cosmos/evm/pull/440) Enforce app creator returning application implement AppWithPendingTxStream in build time.
 
 ### STATE BREAKING
 

evmd/app.go

@@ -132,6 +132,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/staking"
 	stakingkeeper "github.com/cosmos/cosmos-sdk/x/staking/keeper"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
+	cosmosevmserver "github.com/cosmos/evm/server"
 )
 
 func init() {
@@ -147,9 +148,9 @@ const appName = "evmd"
 var defaultNodeHome string
 
 var (
-	_ runtime.AppI            = (*EVMD)(nil)
-	_ servertypes.Application = (*EVMD)(nil)
-	_ ibctesting.TestingApp   = (*EVMD)(nil)
+	_ runtime.AppI                = (*EVMD)(nil)
+	_ cosmosevmserver.Application = (*EVMD)(nil)
+	_ ibctesting.TestingApp       = (*EVMD)(nil)
 )
 
 // EVMD extends an ABCI application, but with most of its parameters exported.

evmd/cmd/evmd/cmd/root.go

@@ -175,14 +175,17 @@ func initRootCmd(rootCmd *cobra.Command, evmApp *evmd.EVMD) {
 	cfg.Seal()
 
 	defaultNodeHome := evmdconfig.MustGetDefaultNodeHome()
+	sdkAppCreator := func(l log.Logger, d dbm.DB, w io.Writer, ao servertypes.AppOptions) servertypes.Application {
+		return newApp(l, d, w, ao)
+	}
 	rootCmd.AddCommand(
 		genutilcli.InitCmd(evmApp.BasicModuleManager, defaultNodeHome),
 		genutilcli.Commands(evmApp.TxConfig(), evmApp.BasicModuleManager, defaultNodeHome),
 		cmtcli.NewCompletionCmd(rootCmd, true),
 		debug.Cmd(),
 		confixcmd.ConfigCommand(),
-		pruning.Cmd(newApp, defaultNodeHome),
-		snapshot.Cmd(newApp),
+		pruning.Cmd(sdkAppCreator, defaultNodeHome),
+		snapshot.Cmd(sdkAppCreator),
 		NewTestnetCmd(evmApp.BasicModuleManager, banktypes.GenesisBalancesIterator{}, appCreator{}),
 	)
 
@@ -272,7 +275,7 @@ func newApp(
 	db dbm.DB,
 	traceStore io.Writer,
 	appOpts servertypes.AppOptions,
-) servertypes.Application {
+) cosmosevmserver.Application {
 	var cache storetypes.MultiStorePersistentCache
 
 	if cast.ToBool(appOpts.Get(sdkserver.FlagInterBlockCache)) {

server/start.go

@@ -34,6 +34,7 @@ import (
 	cosmosevmtypes "github.com/cosmos/evm/types"
 
 	errorsmod "cosmossdk.io/errors"
+	"cosmossdk.io/log"
 	pruningtypes "cosmossdk.io/store/pruning/types"
 
 	"github.com/cosmos/cosmos-sdk/client"
@@ -53,6 +54,14 @@ import (
 // DBOpener is a function to open `application.db`, potentially with customized options.
 type DBOpener func(opts types.AppOptions, rootDir string, backend dbm.BackendType) (dbm.DB, error)
 
+type Application interface {
+	types.Application
+	AppWithPendingTxStream
+}
+
+// AppCreator is a function that allows us to lazily initialize an application implementing with AppWithPendingTxStream.
+type AppCreator func(log.Logger, dbm.DB, io.Writer, types.AppOptions) Application
+
 // StartOptions defines options that can be customized in `StartCmd`
 type StartOptions struct {
 	AppCreator      types.AppCreator
@@ -61,9 +70,11 @@ type StartOptions struct {
 }
 
 // NewDefaultStartOptions use the default db opener provided in tm-db.
-func NewDefaultStartOptions(appCreator types.AppCreator, defaultNodeHome string) StartOptions {
+func NewDefaultStartOptions(appCreator AppCreator, defaultNodeHome string) StartOptions {
 	return StartOptions{
-		AppCreator:      appCreator,
+		AppCreator: func(l log.Logger, d dbm.DB, w io.Writer, ao types.AppOptions) types.Application {
+			return appCreator(l, d, w, ao)
+		},
 		DefaultNodeHome: defaultNodeHome,
 		DBOpener:        cosmosevmserverconfig.OpenDB,
 	}