Accept zero address as to when posting transactions

safe_transaction_service/history/serializers.py

@@ -147,6 +147,7 @@ def save(self, **kwargs):
 
 
 class SafeMultisigTransactionSerializer(SafeMultisigTxSerializerV1):
+    to = EthereumAddressField(allow_zero_address=True, allow_sentinel_address=True)
     contract_transaction_hash = Sha3HashField()
     sender = EthereumAddressField()
     # TODO Make signature mandatory

safe_transaction_service/history/tests/test_views.py

@@ -1407,6 +1407,54 @@ def test_post_multisig_transactions(self):
         )
         self.assertEqual(response.status_code, status.HTTP_422_UNPROCESSABLE_ENTITY)
 
+    def test_post_multisig_transaction_with_zero_to(self):
+        safe_owner_1 = Account.create()
+        safe = self.deploy_test_safe(owners=[safe_owner_1.address])
+        safe_address = safe.address
+
+        response = self.client.get(
+            reverse("v1:history:multisig-transactions", args=(safe_address,)),
+            format="json",
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.data["count"], 0)
+
+        data = {
+            "to": NULL_ADDRESS,
+            "value": 100000000000000000,
+            "data": None,
+            "operation": 0,
+            "nonce": 0,
+            "safeTxGas": 0,
+            "baseGas": 0,
+            "gasPrice": 0,
+            "gasToken": "0x0000000000000000000000000000000000000000",
+            "refundReceiver": "0x0000000000000000000000000000000000000000",
+            # "contractTransactionHash": "0x1c2c77b29086701ccdda7836c399112a9b715c6a153f6c8f75c84da4297f60d3",
+            "sender": safe_owner_1.address,
+        }
+        safe_tx = safe.build_multisig_tx(
+            data["to"],
+            data["value"],
+            data["data"],
+            data["operation"],
+            data["safeTxGas"],
+            data["baseGas"],
+            data["gasPrice"],
+            data["gasToken"],
+            data["refundReceiver"],
+            safe_nonce=data["nonce"],
+        )
+        data["contractTransactionHash"] = safe_tx.safe_tx_hash.hex()
+        response = self.client.post(
+            reverse("v1:history:multisig-transactions", args=(safe_address,)),
+            format="json",
+            data=data,
+        )
+        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+        multisig_transaction_db = MultisigTransaction.objects.first()
+        self.assertFalse(multisig_transaction_db.trusted)
+
     def test_post_multisig_transaction_with_1271_signature(self):
         account = Account.create()
         safe_owner = self.deploy_test_safe(owners=[account.address])