refactor: optimize fee calculation

CHANGELOG.md

@@ -49,6 +49,9 @@ As this project is pre 1.0, breaking changes may happen for minor version bumps.
 - feat: Add `Server.loadAccount` to load the `Account` object used for building transactions, supporting `MuxedAccount`.
 - feat: Add support for `MuxedAccount` to `SorobanServer.getAccount`.
 - feat: `FeeBumpTransaction` supports transactions that include Soroban operations.
+- refactor: `TransactionBuilder#TransactionBuilder(Transaction)` has been removed, because the TransactionBuilder constructed from the transaction may be inconsistent with what the user expects.
+- fix: When calling `TransactionBuilder.build()`, the Soroban resource fee will be included in the `fee` of the built transaction.
+- fix: fix the issue where invoking `SorobanServer.prepareTransaction` for transactions that have already set `SorobanData` could result in unexpected high fees.
 
 ## 0.44.0
 ### Update

src/main/java/org/stellar/sdk/SorobanServer.java

@@ -471,8 +471,11 @@ private Transaction assembleTransaction(
           "unsupported transaction: must contain exactly one InvokeHostFunctionOperation, BumpSequenceOperation, or RestoreFootprintOperation");
     }
 
-    // TODO: exclude exists soroban resource fee from tx fee
     long classicFeeNum = transaction.getFee();
+    if (transaction.getSorobanData() != null) {
+      classicFeeNum -= transaction.getSorobanData().getResourceFee().getInt64();
+    }
+
     long minResourceFeeNum =
         Optional.ofNullable(simulateTransactionResponse.getMinResourceFee()).orElse(0L);
     long fee = classicFeeNum + minResourceFeeNum;

src/main/java/org/stellar/sdk/TransactionBuilder.java

@@ -4,7 +4,6 @@
 
 import java.math.BigInteger;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import lombok.NonNull;
@@ -38,31 +37,6 @@ public TransactionBuilder(
     preconditions = TransactionPreconditions.builder().build();
   }
 
-  /**
-   * Construct a new transaction builder from a transaction.
-   *
-   * @param transaction the transaction to rebuild
-   */
-  public TransactionBuilder(Transaction transaction) {
-    AbstractTransaction abstractTransaction =
-        Transaction.fromEnvelopeXdr(transaction.toEnvelopeXdrBase64(), transaction.getNetwork());
-
-    if (!(abstractTransaction instanceof Transaction)) {
-      // This should never happen
-      throw new IllegalArgumentException(
-          "TransactionBuilder can only be used to rebuild a Transaction");
-    }
-    Transaction tx = (Transaction) abstractTransaction;
-
-    this.sourceAccount = new Account(tx.getSourceAccount(), tx.getSequenceNumber() - 1);
-    this.memo = tx.getMemo();
-    this.operations = Arrays.asList(tx.getOperations());
-    this.baseFee = tx.getFee() / tx.getOperations().length;
-    this.network = tx.getNetwork();
-    this.preconditions = tx.getPreconditions();
-    this.sorobanData = tx.getSorobanData();
-  }
-
   public int getOperationsCount() {
     return operations.size();
   }
@@ -204,10 +178,16 @@ public Transaction build() {
     long sequenceNumber = sourceAccount.getIncrementedSequenceNumber();
     Operation[] operations = new Operation[this.operations.size()];
     operations = this.operations.toArray(operations);
+
+    long fee = operations.length * baseFee;
+    if (sorobanData != null) {
+      fee += sorobanData.getResourceFee().getInt64();
+    }
+
     Transaction transaction =
         new Transaction(
             sourceAccount.getAccountId(),
-            operations.length * baseFee,
+            fee,
             sequenceNumber,
             operations,
             memo,

src/test/java/org/stellar/sdk/SorobanServerTest.java

@@ -1048,8 +1048,8 @@ public void testPrepareTransactionWithSorobanData()
             + "  \"jsonrpc\": \"2.0\",\n"
             + "  \"id\": \"7a469b9d6ed4444893491be530862ce3\",\n"
             + "  \"result\": {\n"
-            + "    \"transactionData\": \"AAAAAAAAAAIAAAAGAAAAAem354u9STQWq5b3Ed1j9tOemvL7xV0NPwhn4gXg0AP8AAAAFAAAAAEAAAAH8dTe2OoI0BnhlDbH0fWvXmvprkBvBAgKIcL9busuuMEAAAABAAAABgAAAAHpt+eLvUk0FquW9xHdY/bTnpry+8VdDT8IZ+IF4NAD/AAAABAAAAABAAAAAgAAAA8AAAAHQ291bnRlcgAAAAASAAAAAAAAAABYt8SiyPKXqo89JHEoH9/M7K/kjlZjMT7BjhKnPsqYoQAAAAEAHifGAAAFlAAAAIgAAAAAAAAAAg==\",\n"
-            + "    \"minResourceFee\": \"58181\",\n"
+            + "    \"transactionData\": \"AAAAAAAAAAEAAAAGAAAAAdeSi3LCcDzP6vfrn/TvTVBKVai5efybRQ6iyEK00c5hAAAAFAAAAAEAAAACAAAAAAAAAABPFZKkWLE8Tlrm5Jx81FUrXpm6EhpW/s8TXPUyf0D5PgAAAAAAAAAAbjEdZhNooxW4Z5oCpgPDCmGnVRwOxutuDO14EQ4kFmoAA3kUAAACGAAAASAAAAAAAAG4Sw==\",\n"
+            + "    \"minResourceFee\": \"12500\",\n"
             + "    \"events\": [\n"
             + "      \"AAAAAQAAAAAAAAAAAAAAAgAAAAAAAAADAAAADwAAAAdmbl9jYWxsAAAAAA0AAAAg6bfni71JNBarlvcR3WP2056a8vvFXQ0/CGfiBeDQA/wAAAAPAAAACWluY3JlbWVudAAAAAAAABAAAAABAAAAAgAAABIAAAAAAAAAAFi3xKLI8peqjz0kcSgf38zsr+SOVmMxPsGOEqc+ypihAAAAAwAAAAo=\",\n"
             + "      \"AAAAAQAAAAAAAAAB6bfni71JNBarlvcR3WP2056a8vvFXQ0/CGfiBeDQA/wAAAACAAAAAAAAAAIAAAAPAAAACWZuX3JldHVybgAAAAAAAA8AAAAJaW5jcmVtZW50AAAAAAAAAwAAABQ=\"\n"
@@ -1126,7 +1126,7 @@ public MockResponse dispatch(@NotNull RecordedRequest recordedRequest)
 
     SorobanTransactionData sorobanData =
         SorobanTransactionData.fromXdrBase64(
-            "AAAAAAAAAAIAAAAGAAAAAem354u9STQWq5b3Ed1j9tOemvL7xV0NPwhn4gXg0AP8AAAAFAAAAAEAAAAH8dTe2OoI0BnhlDbH0fWvXmvprkBvBAgKIcL9busuuMEAAAABAAAABgAAAAHpt+eLvUk0FquW9xHdY/bTnpry+8VdDT8IZ+IF4NAD/AAAABAAAAABAAAAAgAAAA8AAAAHQ291bnRlcgAAAAASAAAAAAAAAABYt8SiyPKXqo89JHEoH9/M7K/kjlZjMT7BjhKnPsqYoQAAAAEAHifGAAAFlAAAAIgAAAAAAAAAAg==");
+            "AAAAAAAAAAEAAAAGAAAAAdeSi3LCcDzP6vfrn/TvTVBKVai5efybRQ6iyEK00c5hAAAAFAAAAAEAAAACAAAAAAAAAABPFZKkWLE8Tlrm5Jx81FUrXpm6EhpW/s8TXPUyf0D5PgAAAAAAAAAAbjEdZhNooxW4Z5oCpgPDCmGnVRwOxutuDO14EQ4kFmoAA3kUAAACGAAAASAAAAAAAAG4Sw==");
     InvokeHostFunctionOperation operation =
         InvokeHostFunctionOperation.builder()
             .hostFunction(
@@ -1140,7 +1140,7 @@ public MockResponse dispatch(@NotNull RecordedRequest recordedRequest)
     Transaction expectedTx =
         new Transaction(
             transaction.getSourceAccount(),
-            transaction.getFee() + 58181L,
+            50000 + 12500, // baseFee + Soroban Fee
             transaction.getSequenceNumber(),
             new Operation[] {operation},
             transaction.getMemo(),

src/test/java/org/stellar/sdk/TransactionBuilderTest.java

@@ -4,12 +4,10 @@
 
 import java.io.IOException;
 import java.math.BigInteger;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import org.junit.Test;
 import org.stellar.sdk.exception.FormatException;
-import org.stellar.sdk.operations.BumpSequenceOperation;
 import org.stellar.sdk.operations.CreateAccountOperation;
 import org.stellar.sdk.operations.InvokeHostFunctionOperation;
 import org.stellar.sdk.xdr.*;
@@ -930,58 +928,6 @@ public void testNoNetworkSet() throws FormatException {
     }
   }
 
-  @Test
-  public void testBuilderFromTx() {
-    KeyPair source =
-        KeyPair.fromSecretSeed("SCH27VUZZ6UAKB67BDNF6FA42YMBMQCBKXWGMFD5TZ6S5ZZCZFLRXKHS");
-
-    Account account = new Account(source.getAccountId(), 2908908335136768L);
-    BumpSequenceOperation operation0 = BumpSequenceOperation.builder().bumpTo(1L).build();
-    BumpSequenceOperation operation1 = BumpSequenceOperation.builder().bumpTo(2L).build();
-    LedgerKey ledgerKey =
-        LedgerKey.builder()
-            .discriminant(LedgerEntryType.ACCOUNT)
-            .account(
-                LedgerKey.LedgerKeyAccount.builder()
-                    .accountID(
-                        KeyPair.fromAccountId(
-                                "GB7TAYRUZGE6TVT7NHP5SMIZRNQA6PLM423EYISAOAP3MKYIQMVYP2JO")
-                            .getXdrAccountId())
-                    .build())
-            .build();
-    SorobanTransactionData sorobanData =
-        SorobanTransactionData.builder()
-            .resources(
-                SorobanResources.builder()
-                    .footprint(
-                        LedgerFootprint.builder()
-                            .readOnly(new LedgerKey[] {ledgerKey})
-                            .readWrite(new LedgerKey[] {})
-                            .build())
-                    .readBytes(new Uint32(new XdrUnsignedInteger(699)))
-                    .writeBytes(new Uint32(new XdrUnsignedInteger(0)))
-                    .instructions(new Uint32(new XdrUnsignedInteger(34567)))
-                    .build())
-            .resourceFee(new Int64(100L))
-            .ext(ExtensionPoint.builder().discriminant(0).build())
-            .build();
-
-    Transaction transaction =
-        new Transaction(
-            account.getAccountId(),
-            980,
-            account.getIncrementedSequenceNumber(),
-            new org.stellar.sdk.operations.Operation[] {operation0, operation1},
-            new MemoText("hello"),
-            new TransactionPreconditions(
-                null, null, BigInteger.ZERO, 0, new ArrayList<>(), new TimeBounds(100, 200)),
-            sorobanData, // For testing purposes, it is impossible to occur in a real environment.
-            Network.PUBLIC);
-
-    TransactionBuilder builder = new TransactionBuilder(transaction);
-    assertEquals(transaction, builder.build());
-  }
-
   @Test
   public void voidBuilderSorobanDataXdrString() {
     KeyPair source =