Perform fee padding in a larger bit width of integers

cmd/crates/soroban-rpc/src/txn.rs

@@ -315,13 +315,17 @@ pub fn assemble(
 
     // update the fees of the actual transaction to meet the minimum resource fees.
     let classic_transaction_fees = crate::DEFAULT_TRANSACTION_FEES;
-    // Pad the fees up by 15% for a bit of wiggle room.
-    tx.fee = (tx.fee.max(
-        classic_transaction_fees
-            + u32::try_from(simulation.min_resource_fee)
-                .map_err(|_| Error::LargeFee(simulation.min_resource_fee))?,
-    ) * 115)
-        / 100;
+
+    // Pad the fees up by 15% for a bit of wiggle room
+    let padded_fee = u64::from(
+        tx.fee.max(
+            classic_transaction_fees
+                + u32::try_from(simulation.min_resource_fee)
+                    .map_err(|_| Error::LargeFee(simulation.min_resource_fee))?,
+        ),
+    ) / 100
+        * 115;
+    tx.fee = u32::try_from(padded_fee).map_err(|_| Error::LargeFee(padded_fee))?;
 
     tx.operations = vec![op].try_into()?;
     tx.ext = TransactionExt::V1(transaction_data);