Obtain simulation protocol version dynamically

cmd/soroban-rpc/internal/jsonrpc.go

@@ -208,7 +208,7 @@ func NewJSONRPCHandler(cfg *config.Config, params HandlerParams) Handler {
 		},
 		{
 			methodName:           "simulateTransaction",
-			underlyingHandler:    methods.NewSimulateTransactionHandler(params.Logger, params.LedgerEntryReader, params.LedgerReader, params.PreflightGetter),
+			underlyingHandler:    methods.NewSimulateTransactionHandler(params.Logger, params.LedgerEntryReader, params.LedgerReader, params.Daemon, params.PreflightGetter),
 			longName:             "simulate_transaction",
 			queueLimit:           cfg.RequestBacklogSimulateTransactionQueueLimit,
 			requestDurationLimit: cfg.MaxSimulateTransactionExecutionDuration,

cmd/soroban-rpc/internal/methods/simulate_transaction.go

@@ -12,6 +12,7 @@ import (
 	"github.com/stellar/go/support/log"
 	"github.com/stellar/go/xdr"
 
+	"github.com/stellar/soroban-rpc/cmd/soroban-rpc/internal/daemon/interfaces"
 	"github.com/stellar/soroban-rpc/cmd/soroban-rpc/internal/db"
 	"github.com/stellar/soroban-rpc/cmd/soroban-rpc/internal/preflight"
 )
@@ -156,7 +157,7 @@ type PreflightGetter interface {
 }
 
 // NewSimulateTransactionHandler returns a json rpc handler to run preflight simulations
-func NewSimulateTransactionHandler(logger *log.Entry, ledgerEntryReader db.LedgerEntryReader, ledgerReader db.LedgerReader, getter PreflightGetter) jrpc2.Handler {
+func NewSimulateTransactionHandler(logger *log.Entry, ledgerEntryReader db.LedgerEntryReader, ledgerReader db.LedgerReader, daemon interfaces.Daemon, getter PreflightGetter) jrpc2.Handler {
 
 	return NewHandler(func(ctx context.Context, request SimulateTransactionRequest) SimulateTransactionResponse {
 		var txEnvelope xdr.TransactionEnvelope
@@ -212,7 +213,7 @@ func NewSimulateTransactionHandler(logger *log.Entry, ledgerEntryReader db.Ledge
 				Error: err.Error(),
 			}
 		}
-		bucketListSize, err := getBucketListSize(ctx, ledgerReader, latestLedger)
+		bucketListSize, protocolVersion, err := getBucketListSizeAndProtocolVersion(ctx, ledgerReader, latestLedger)
 		if err != nil {
 			return SimulateTransactionResponse{
 				Error: err.Error(),
@@ -230,6 +231,7 @@ func NewSimulateTransactionHandler(logger *log.Entry, ledgerEntryReader db.Ledge
 			OperationBody:     op.Body,
 			Footprint:         footprint,
 			ResourceConfig:    resource_config,
+			ProtocolVersion:   protocolVersion,
 		}
 		result, err := getter.GetPreflight(ctx, params)
 		if err != nil {
@@ -284,17 +286,17 @@ func base64EncodeSlice(in [][]byte) []string {
 	return result
 }
 
-func getBucketListSize(ctx context.Context, ledgerReader db.LedgerReader, latestLedger uint32) (uint64, error) {
+func getBucketListSizeAndProtocolVersion(ctx context.Context, ledgerReader db.LedgerReader, latestLedger uint32) (uint64, uint32, error) {
 	// obtain bucket size
 	var closeMeta, ok, err = ledgerReader.GetLedger(ctx, latestLedger)
 	if err != nil {
-		return 0, err
+		return 0, 0, err
 	}
 	if !ok {
-		return 0, fmt.Errorf("missing meta for latest ledger (%d)", latestLedger)
+		return 0, 0, fmt.Errorf("missing meta for latest ledger (%d)", latestLedger)
 	}
 	if closeMeta.V != 1 {
-		return 0, fmt.Errorf("latest ledger (%d) meta has unexpected verion (%d)", latestLedger, closeMeta.V)
+		return 0, 0, fmt.Errorf("latest ledger (%d) meta has unexpected verion (%d)", latestLedger, closeMeta.V)
 	}
-	return uint64(closeMeta.V1.TotalByteSizeOfBucketList), nil
+	return uint64(closeMeta.V1.TotalByteSizeOfBucketList), uint32(closeMeta.V1.LedgerHeader.Header.LedgerVersion), nil
 }

cmd/soroban-rpc/internal/preflight/pool.go

@@ -156,6 +156,7 @@ func (pwp *PreflightWorkerPool) GetPreflight(ctx context.Context, params Preflig
 		Footprint:         params.Footprint,
 		ResourceConfig:    params.ResourceConfig,
 		EnableDebug:       pwp.enableDebug,
+		ProtocolVersion:   params.ProtocolVersion,
 	}
 	resultC := make(chan workerResult)
 	select {

cmd/soroban-rpc/internal/preflight/preflight.go

@@ -91,6 +91,7 @@ type PreflightGetterParameters struct {
 	OperationBody     xdr.OperationBody
 	Footprint         xdr.LedgerFootprint
 	ResourceConfig    ResourceConfig
+	ProtocolVersion   uint32
 }
 
 type PreflightParameters struct {
@@ -103,6 +104,7 @@ type PreflightParameters struct {
 	BucketListSize    uint64
 	ResourceConfig    ResourceConfig
 	EnableDebug       bool
+	ProtocolVersion   uint32
 }
 
 type XDRDiff struct {
@@ -174,7 +176,7 @@ func getLedgerInfo(params PreflightParameters) (C.ledger_info_t, error) {
 	li := C.ledger_info_t{
 		network_passphrase: C.CString(params.NetworkPassphrase),
 		sequence_number:    C.uint32_t(simulationLedgerSeq),
-		protocol_version:   20,
+		protocol_version:   C.uint32_t(params.ProtocolVersion),
 		timestamp:          C.uint64_t(time.Now().Unix()),
 		// Current base reserve is 0.5XLM (in stroops)
 		base_reserve: 5_000_000,

cmd/soroban-rpc/internal/preflight/preflight_test.go

@@ -361,6 +361,7 @@ func getPreflightParameters(t testing.TB, dbConfig *preflightParametersDBConfig)
 		NetworkPassphrase: "foo",
 		LedgerEntryReadTx: ledgerEntryReadTx,
 		BucketListSize:    200,
+		ProtocolVersion:   20,
 	}
 	return params
 }