feat(core): add migrations registering (#19370)

Co-authored-by: Facundo Medica <14063057+facundomedica@users.noreply.github.com>

core/appmodule/migrations.go

@@ -0,0 +1,16 @@
+package appmodule
+
+import "context"
+
+type MigrationRegistrar interface {
+	// Register registers an in-place store migration for a module. The
+	// handler is a migration script to perform in-place migrations from version
+	// `fromVersion` to version `fromVersion+1`.
+	//
+	// EACH TIME a module's ConsensusVersion increments, a new migration MUST
+	// be registered using this function. If a migration handler is missing for
+	// a particular function, the upgrade logic (see RunMigrations function)
+	// will panic. If the ConsensusVersion bump does not introduce any store
+	// changes, then a no-op function must be registered here.
+	Register(moduleName string, fromVersion uint64, handler func(context.Context) error) error
+}

core/appmodule/module.go

@@ -39,17 +39,12 @@ type HasServices interface {
 	RegisterServices(grpc.ServiceRegistrar) error
 }
 
-// HasPrepareCheckState is an extension interface that contains information about the AppModule
-// and PrepareCheckState.
-type HasPrepareCheckState interface {
+// HasMigrations is the extension interface that modules should implement to register migrations.
+type HasMigrations interface {
 	AppModule
-	PrepareCheckState(context.Context) error
-}
 
-// HasPrecommit is an extension interface that contains information about the AppModule and Precommit.
-type HasPrecommit interface {
-	AppModule
-	Precommit(context.Context) error
+	// RegisterMigrations registers the module's migrations with the app's migrator.
+	RegisterMigrations(MigrationRegistrar) error
 }
 
 // ResponsePreBlock represents the response from the PreBlock method.
@@ -100,3 +95,18 @@ type HasMsgHandler interface {
 	// RegisterMsgHandlers is implemented by the module that will register msg handlers.
 	RegisterMsgHandlers(router MsgHandlerRouter)
 }
+
+// ---------------------------------------------------------------------------- //
+
+// HasPrepareCheckState is an extension interface that contains information about the AppModule
+// and PrepareCheckState.
+type HasPrepareCheckState interface {
+	AppModule
+	PrepareCheckState(context.Context) error
+}
+
+// HasPrecommit is an extension interface that contains information about the AppModule and Precommit.
+type HasPrecommit interface {
+	AppModule
+	Precommit(context.Context) error
+}