From d25915ca1dd5d25d8a12909d251b165ff6b404ca Mon Sep 17 00:00:00 2001
From: Denis Angell <dangell@transia.co>
Date: Thu, 8 Jan 2026 08:48:39 -0500
Subject: [PATCH] fix: Reorder Batch Preflight Errors (#6176)

This change fixes https://github.com/XRPLF/rippled/issues/6058.
---
 src/test/app/Batch_test.cpp       | 32 +++++++++++++++++++++++++++++++
 src/xrpld/app/tx/detail/Batch.cpp | 20 +++++++++----------
 2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/src/test/app/Batch_test.cpp b/src/test/app/Batch_test.cpp
index 1dac56d2d9..328cb63dbe 100644
--- a/src/test/app/Batch_test.cpp
+++ b/src/test/app/Batch_test.cpp
@@ -420,6 +420,38 @@ class Batch_test : public beast::unit_test::suite
             env.close();
         }
 
+        // temBAD_FEE: Inner txn with negative fee
+        {
+            auto const seq = env.seq(alice);
+            auto const batchFee = batch::calcBatchFee(env, 0, 2);
+            auto tx1 = batch::inner(pay(alice, bob, XRP(1)), seq + 1);
+            tx1[jss::Fee] = "-1";
+            env(batch::outer(alice, seq, batchFee, tfAllOrNothing),
+                tx1,
+                batch::inner(pay(alice, bob, XRP(2)), seq + 2),
+                ter(temBAD_FEE));
+            env.close();
+        }
+
+        // temBAD_FEE: Inner txn with non-integer fee
+        {
+            auto const seq = env.seq(alice);
+            auto const batchFee = batch::calcBatchFee(env, 0, 2);
+            auto tx1 = batch::inner(pay(alice, bob, XRP(1)), seq + 1);
+            tx1[jss::Fee] = "1.5";
+            try
+            {
+                env(batch::outer(alice, seq, batchFee, tfAllOrNothing),
+                    tx1,
+                    batch::inner(pay(alice, bob, XRP(2)), seq + 2));
+                fail("Expected parse_error for fractional fee");
+            }
+            catch (jtx::parse_error const&)
+            {
+                BEAST_EXPECT(true);
+            }
+        }
+
         // temSEQ_AND_TICKET: Batch: inner txn cannot have both Sequence
         // and TicketSequence.
         {
diff --git a/src/xrpld/app/tx/detail/Batch.cpp b/src/xrpld/app/tx/detail/Batch.cpp
index 8c1c515021..87c6907cc4 100644
--- a/src/xrpld/app/tx/detail/Batch.cpp
+++ b/src/xrpld/app/tx/detail/Batch.cpp
@@ -324,6 +324,16 @@ Batch::preflight(PreflightContext const& ctx)
             }
         }
 
+        // Check that the Fee is native asset (XRP) and zero
+        if (auto const fee = stx.getFieldAmount(sfFee);
+            !fee.native() || fee.xrp() != beast::zero)
+        {
+            JLOG(ctx.j.debug()) << "BatchTrace[" << parentBatchId << "]: "
+                                << "inner txn must have a fee of 0. "
+                                << "txID: " << hash;
+            return temBAD_FEE;
+        }
+
         auto const innerAccount = stx.getAccountID(sfAccount);
         if (auto const preflightResult = ripple::preflight(
                 ctx.app, ctx.rules, parentBatchId, stx, tapBATCH, ctx.j);
@@ -336,16 +346,6 @@ Batch::preflight(PreflightContext const& ctx)
             return temINVALID_INNER_BATCH;
         }
 
-        // Check that the fee is zero
-        if (auto const fee = stx.getFieldAmount(sfFee);
-            !fee.native() || fee.xrp() != beast::zero)
-        {
-            JLOG(ctx.j.debug()) << "BatchTrace[" << parentBatchId << "]: "
-                                << "inner txn must have a fee of 0. "
-                                << "txID: " << hash;
-            return temBAD_FEE;
-        }
-
         // Check that Sequence and TicketSequence are not both present
         if (stx.isFieldPresent(sfTicketSequence) &&
             stx.getFieldU32(sfSequence) != 0)