fix: fix the issue where sending assets using Transaction.append_payment_to_contract_op fails when the sender's account is the same as the asset issuer's account. (#1029)

Author: overcat

CHANGELOG.md

@@ -3,6 +3,9 @@ Release History
 
 ### Pending
 
+#### Update
+- fix: fix the issue where sending assets using `Transaction.append_payment_to_contract_op` fails when the sender's account is the same as the asset issuer's account. ([#1029](https://github.com/StellarCN/py-stellar-base/pull/1029))
+
 ### Version 12.2.0
 
 #### Update

stellar_sdk/transaction_builder.py

@@ -1602,17 +1602,20 @@ def append_payment_to_contract_op(
                 contract_instance_ledger_key,
             ]
             read_write = [
-                stellar_xdr.LedgerKey(
-                    type=stellar_xdr.LedgerEntryType.TRUSTLINE,
-                    trust_line=stellar_xdr.LedgerKeyTrustLine(
-                        account_id=Keypair.from_public_key(
-                            from_address
-                        ).xdr_account_id(),
-                        asset=asset.to_trust_line_asset_xdr_object(),
-                    ),
-                ),
                 balance_ledger_key,
             ]
+            if asset.issuer != from_address:
+                read_write.append(
+                    stellar_xdr.LedgerKey(
+                        type=stellar_xdr.LedgerEntryType.TRUSTLINE,
+                        trust_line=stellar_xdr.LedgerKeyTrustLine(
+                            account_id=Keypair.from_public_key(
+                                from_address
+                            ).xdr_account_id(),
+                            asset=asset.to_trust_line_asset_xdr_object(),
+                        ),
+                    ),
+                )
 
         soroban_data = (
             SorobanDataBuilder()

tests/test_transaction_builder.py

@@ -1291,6 +1291,73 @@ def test_append_payment_to_contract_op_with_different_op_source(self):
 
         server.close()
 
+    @pytest.mark.integration
+    def test_append_payment_to_contract_op_with_asset_issuer_as_sender(self):
+        kp = Keypair.random()
+
+        asset = Asset("CAT", kp.public_key)
+        amount1 = "100.125"
+        amount2 = "120.7891"
+
+        integration_utils.fund_account(kp.public_key)
+        integration_utils.create_asset_contract(asset, kp)
+        destination = integration_utils.get_random_contract_id(kp)
+
+        server = Server(horizon_url=integration_utils.HORIZON_URL)
+        source = server.load_account(kp.public_key)
+        tx1 = (
+            TransactionBuilder(
+                source_account=source,
+                network_passphrase=integration_utils.NETWORK_PASSPHRASE,
+                base_fee=100,
+            )
+            .append_payment_to_contract_op(destination, asset, amount1)
+            .set_timeout(30)
+            .build()
+        )
+        tx1.sign(kp)
+        server.submit_transaction(tx1)
+        assert (
+            integration_utils.get_balance_for_contract(
+                destination, asset, kp.public_key
+            )
+            == 1001250000
+        )
+
+        tx2 = (
+            TransactionBuilder(
+                source_account=source,
+                network_passphrase=integration_utils.NETWORK_PASSPHRASE,
+                base_fee=100,
+            )
+            .append_payment_to_contract_op(destination, asset, amount2)
+            .set_timeout(30)
+            .build()
+        )
+        tx2.sign(kp)
+        server.submit_transaction(tx2)
+        assert (
+            integration_utils.get_balance_for_contract(
+                destination, asset, kp.public_key
+            )
+            == 2209141000
+        )
+
+        tx3 = (
+            TransactionBuilder(
+                source_account=source,
+                network_passphrase=integration_utils.NETWORK_PASSPHRASE,
+                base_fee=100,
+            )
+            .append_restore_asset_balance_entry_op(destination, asset)
+            .set_timeout(30)
+            .build()
+        )
+        tx3.sign(kp)
+        server.submit_transaction(tx3)
+
+        server.close()
+
     def test_append_payment_to_stellar_address_raise(self):
         kp = Keypair.random()
         asset = Asset.native()