From 9264136b36ef9e248f28cf65016bd08975938c32 Mon Sep 17 00:00:00 2001
From: tequ <git@tequ.dev>
Date: Fri, 10 Apr 2026 17:41:33 +0900
Subject: [PATCH] fix deleteAMMTrustLine Reads Sponsor Fields After They Are
 Erased

---
 .../ledger/helpers/RippleStateHelpers.cpp     |  6 +-
 src/test/app/Sponsor_test.cpp                 | 57 +++++++++++++++++++
 2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/src/libxrpl/ledger/helpers/RippleStateHelpers.cpp b/src/libxrpl/ledger/helpers/RippleStateHelpers.cpp
index cc01220738..c5730e46d0 100644
--- a/src/libxrpl/ledger/helpers/RippleStateHelpers.cpp
+++ b/src/libxrpl/ledger/helpers/RippleStateHelpers.cpp
@@ -781,6 +781,9 @@ deleteAMMTrustLine(
     if (ammAccountID && (low != *ammAccountID && high != *ammAccountID))
         return terNO_AMM;
 
+    auto const sponsorSle =
+        getLedgerEntryReserveSponsor(view, sleState, !ammLow ? sfLowSponsor : sfHighSponsor);
+
     if (auto const ter = trustDelete(view, sleState, low, high, j); !isTesSuccess(ter))
     {
         JLOG(j.error()) << "deleteAMMTrustLine: failed to delete the trustline.";
@@ -791,10 +794,7 @@ deleteAMMTrustLine(
     if ((sleState->getFlags() & uFlags) == 0u)
         return tecINTERNAL;  // LCOV_EXCL_LINE
 
-    auto const sponsorSle =
-        getLedgerEntryReserveSponsor(view, sleState, !ammLow ? sfLowSponsor : sfHighSponsor);
     adjustOwnerCount(view, !ammLow ? sleLow : sleHigh, sponsorSle, -1, j);
-    removeSponsorFromLedgerEntry(sleState, !ammLow ? sfLowSponsor : sfHighSponsor);
 
     return tesSUCCESS;
 }
diff --git a/src/test/app/Sponsor_test.cpp b/src/test/app/Sponsor_test.cpp
index 3cb5d92040..b48c81660e 100644
--- a/src/test/app/Sponsor_test.cpp
+++ b/src/test/app/Sponsor_test.cpp
@@ -2216,6 +2216,63 @@ public:
                 BEAST_EXPECT(sponsoringOwnerCount(env, sponsor) == 0);
             }
         }
+        {
+            // AMMDelete
+            // - remove sponsored LPToken trustlines
+            Env env(
+                *this,
+                envconfig([](std::unique_ptr<Config> cfg) {
+                    cfg->FEES.reference_fee = XRPAmount(1);
+                    return cfg;
+                }),
+                testable_amendments());
+            env.fund(XRP(20'000), alice, gw, sponsor);
+            env.close();
+            env(trust(alice, USD(10'000)));
+            env.close();
+            env(pay(gw, alice, USD(10'000)));
+            env.close();
+
+            AMM amm(env, gw, XRP(10'000), USD(10'000));
+            for (auto i = 0; i < (maxDeletableAMMTrustLines * 2) + 10; ++i)
+            {
+                Account const a{std::to_string(i)};
+                env.fund(XRP(1'000), a);
+                if (cosigning)
+                {
+                    env(trust(a, STAmount{amm.lptIssue(), 10'000}),
+                        sponsor::as(sponsor, spfSponsorReserve),
+                        sig(sfSponsorSignature, sponsor));
+                    env.close();
+                }
+                else
+                {
+                    env(sponsor::set_reserve(sponsor, 0, 1), sponsor::sponseeAcc(a));
+                    env.close();
+                    env(trust(a, STAmount{amm.lptIssue(), 10'000}),
+                        sponsor::as(sponsor, spfSponsorReserve));
+                    env.close();
+                }
+            }
+
+            BEAST_EXPECT(sponsoringOwnerCount(env, sponsor) == maxDeletableAMMTrustLines * 2 + 10);
+
+            // The trustlines are partially deleted.
+            amm.withdrawAll(gw);
+            BEAST_EXPECT(amm.ammExists());
+
+            // AMMDelete has to be called twice to delete AMM.
+            amm.ammDelete(alice, ter(tecINCOMPLETE));
+            BEAST_EXPECT(amm.ammExists());
+
+            // Deletes remaining trustlines and deletes AMM.
+            amm.ammDelete(alice);
+            BEAST_EXPECT(!amm.ammExists());
+            BEAST_EXPECT(!env.le(keylet::ownerDir(amm.ammAccount())));
+
+            BEAST_EXPECT(
+                !env.le(keylet::account(sponsor))->isFieldPresent(sfSponsoringAccountCount));
+        }
     }
 
     void