feat: introduce PreBlock (backport #17421) (#17712)

Co-authored-by: mmsqe <mavis@crypto.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

baseapp/abci.go

@@ -727,6 +727,10 @@ func (app *BaseApp) FinalizeBlock(req *abci.RequestFinalizeBlock) (*abci.Respons
 		}
 	}
 
+	if err := app.preBlock(); err != nil {
+		return nil, err
+	}
+
 	beginBlock, err := app.beginBlock(req)
 	if err != nil {
 		return nil, err

baseapp/baseapp.go

@@ -75,6 +75,7 @@ type BaseApp struct {
 	postHandler sdk.PostHandler // post handler, optional, e.g. for tips
 
 	initChainer          sdk.InitChainer                // ABCI InitChain handler
+	preBlocker           sdk.PreBlocker                 // logic to run before BeginBlocker
 	beginBlocker         sdk.BeginBlocker               // (legacy ABCI) BeginBlock handler
 	endBlocker           sdk.EndBlocker                 // (legacy ABCI) EndBlock handler
 	processProposal      sdk.ProcessProposalHandler     // ABCI ProcessProposal handler
@@ -664,6 +665,26 @@ func (app *BaseApp) cacheTxContext(ctx sdk.Context, txBytes []byte) (sdk.Context
 	return ctx.WithMultiStore(msCache), msCache
 }
 
+func (app *BaseApp) preBlock() error {
+	if app.preBlocker != nil {
+		ctx := app.finalizeBlockState.ctx
+		rsp, err := app.preBlocker(ctx)
+		if err != nil {
+			return err
+		}
+		// rsp.ConsensusParamsChanged is true from preBlocker means ConsensusParams in store get changed
+		// write the consensus parameters in store to context
+		if rsp.ConsensusParamsChanged {
+			ctx = ctx.WithConsensusParams(app.GetConsensusParams(ctx))
+			// GasMeter must be set after we get a context with updated consensus params.
+			gasMeter := app.getBlockGasMeter(ctx)
+			ctx = ctx.WithBlockGasMeter(gasMeter)
+			app.finalizeBlockState.ctx = ctx
+		}
+	}
+	return nil
+}
+
 func (app *BaseApp) beginBlock(req *abci.RequestFinalizeBlock) (sdk.BeginBlock, error) {
 	var (
 		resp sdk.BeginBlock

baseapp/baseapp_test.go

@@ -422,6 +422,9 @@ func TestBaseAppOptionSeal(t *testing.T) {
 	require.Panics(t, func() {
 		suite.baseApp.SetInitChainer(nil)
 	})
+	require.Panics(t, func() {
+		suite.baseApp.SetPreBlocker(nil)
+	})
 	require.Panics(t, func() {
 		suite.baseApp.SetBeginBlocker(nil)
 	})

baseapp/options.go

@@ -158,6 +158,14 @@ func (app *BaseApp) SetInitChainer(initChainer sdk.InitChainer) {
 	app.initChainer = initChainer
 }
 
+func (app *BaseApp) SetPreBlocker(preBlocker sdk.PreBlocker) {
+	if app.sealed {
+		panic("SetPreBlocker() on sealed BaseApp")
+	}
+
+	app.preBlocker = preBlocker
+}
+
 func (app *BaseApp) SetBeginBlocker(beginBlocker sdk.BeginBlocker) {
 	if app.sealed {
 		panic("SetBeginBlocker() on sealed BaseApp")