test: Add a test for anchor outputs in the wallet

test/functional/test_framework/script_util.py

@@ -66,6 +66,7 @@ DUMMY_MIN_OP_RETURN_SCRIPT = CScript([OP_RETURN] + ([OP_0] * (MIN_PADDING - 1)))
 assert len(DUMMY_MIN_OP_RETURN_SCRIPT) == MIN_PADDING
 
 PAY_TO_ANCHOR = CScript([OP_1, bytes.fromhex("4e73")])
+ANCHOR_ADDRESS = "bcrt1pfeesnyr2tx"
 
 def key_to_p2pk_script(key):
     key = check_key(key)

test/functional/test_runner.py

@@ -151,6 +151,7 @@ BASE_SCRIPTS = [
     'rpc_orphans.py',
     'wallet_listreceivedby.py',
     'wallet_abandonconflict.py',
+    'wallet_anchor.py',
     'feature_reindex.py',
     'feature_reindex_readonly.py',
     'wallet_labels.py',

test/functional/wallet_anchor.py

@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+# Copyright (c) 2025-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://www.opensource.org/licenses/mit-license.php.
+
+import time
+
+from test_framework.blocktools import MAX_FUTURE_BLOCK_TIME
+from test_framework.descriptors import descsum_create
+from test_framework.messages import (
+    COutPoint,
+    CTxIn,
+    CTxInWitness,
+    CTxOut,
+)
+from test_framework.script_util import (
+    ANCHOR_ADDRESS,
+    PAY_TO_ANCHOR,
+)
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    assert_raises_rpc_error,
+)
+from test_framework.wallet import MiniWallet
+
+class WalletAnchorTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def test_0_value_anchor_listunspent(self):
+        self.log.info("Test that 0-value anchor outputs are detected as UTXOs")
+
+        # Create an anchor output, and spend it
+        sender = MiniWallet(self.nodes[0])
+        anchor_tx = sender.create_self_transfer(fee_rate=0, version=3)["tx"]
+        anchor_tx.vout.append(CTxOut(0, PAY_TO_ANCHOR))
+        anchor_spend = sender.create_self_transfer(version=3)["tx"]
+        anchor_spend.vin.append(CTxIn(COutPoint(anchor_tx.txid_int, 1), b""))
+        anchor_spend.wit.vtxinwit.append(CTxInWitness())
+        submit_res = self.nodes[0].submitpackage([anchor_tx.serialize().hex(), anchor_spend.serialize().hex()])
+        assert_equal(submit_res["package_msg"], "success")
+        anchor_txid = anchor_tx.txid_hex
+        anchor_spend_txid = anchor_spend.txid_hex
+
+        # Mine each tx in separate blocks
+        self.generateblock(self.nodes[0], sender.get_address(), [anchor_tx.serialize().hex()])
+        anchor_tx_height = self.nodes[0].getblockcount()
+        self.generateblock(self.nodes[0], sender.get_address(), [anchor_spend.serialize().hex()])
+
+        # Mock time forward and generate some blocks to avoid rescanning of latest blocks
+        self.nodes[0].setmocktime(int(time.time()) + MAX_FUTURE_BLOCK_TIME + 1)
+        self.generate(self.nodes[0], 10)
+
+        self.nodes[0].createwallet(wallet_name="anchor", disable_private_keys=True)
+        wallet = self.nodes[0].get_wallet_rpc("anchor")
+        import_res = wallet.importdescriptors([{"desc": descsum_create(f"addr({ANCHOR_ADDRESS})"), "timestamp": "now"}])
+        assert_equal(import_res[0]["success"], True)
+
+        # The wallet should have no UTXOs, and not know of the anchor tx or its spend
+        assert_equal(wallet.listunspent(), [])
+        assert_raises_rpc_error(-5, "Invalid or non-wallet transaction id", wallet.gettransaction, anchor_txid)
+        assert_raises_rpc_error(-5, "Invalid or non-wallet transaction id", wallet.gettransaction, anchor_spend_txid)
+
+        # Rescanning the block containing the anchor so that listunspent will list the output
+        wallet.rescanblockchain(0, anchor_tx_height)
+        utxos = wallet.listunspent()
+        assert_equal(len(utxos), 1)
+        assert_equal(utxos[0]["txid"], anchor_txid)
+        assert_equal(utxos[0]["address"], ANCHOR_ADDRESS)
+        assert_equal(utxos[0]["amount"], 0)
+        wallet.gettransaction(anchor_txid)
+        assert_raises_rpc_error(-5, "Invalid or non-wallet transaction id", wallet.gettransaction, anchor_spend_txid)
+
+        # Rescan the rest of the blockchain to see the anchor was spent
+        wallet.rescanblockchain()
+        assert_equal(wallet.listunspent(), [])
+        wallet.gettransaction(anchor_spend_txid)
+
+    def test_cannot_sign_anchors(self):
+        self.log.info("Test that the wallet cannot spend anchor outputs")
+        for disable_privkeys in [False, True]:
+            self.nodes[0].createwallet(wallet_name=f"anchor_spend_{disable_privkeys}", disable_private_keys=disable_privkeys)
+            wallet = self.nodes[0].get_wallet_rpc(f"anchor_spend_{disable_privkeys}")
+            import_res = wallet.importdescriptors([
+                {"desc": descsum_create(f"addr({ANCHOR_ADDRESS})"), "timestamp": "now"},
+                {"desc": descsum_create(f"raw({PAY_TO_ANCHOR.hex()})"), "timestamp": "now"}
+            ])
+            assert_equal(import_res[0]["success"], disable_privkeys)
+            assert_equal(import_res[1]["success"], disable_privkeys)
+
+        anchor_txid = self.default_wallet.sendtoaddress(ANCHOR_ADDRESS, 1)
+        self.generate(self.nodes[0], 1)
+
+        wallet = self.nodes[0].get_wallet_rpc("anchor_spend_True")
+        utxos = wallet.listunspent()
+        assert_equal(len(utxos), 1)
+        assert_equal(utxos[0]["txid"], anchor_txid)
+        assert_equal(utxos[0]["address"], ANCHOR_ADDRESS)
+        assert_equal(utxos[0]["amount"], 1)
+
+        assert_raises_rpc_error(-4, "Missing solving data for estimating transaction size", wallet.send, [{self.default_wallet.getnewaddress(): 0.9999}])
+        assert_raises_rpc_error(-4, "Error: Private keys are disabled for this wallet", wallet.sendtoaddress, self.default_wallet.getnewaddress(), 0.9999)
+        assert_raises_rpc_error(-4, "Unable to determine the size of the transaction, the wallet contains unsolvable descriptors", wallet.sendall, recipients=[self.default_wallet.getnewaddress()], inputs=utxos)
+        assert_raises_rpc_error(-4, "Unable to determine the size of the transaction, the wallet contains unsolvable descriptors", wallet.sendall, recipients=[self.default_wallet.getnewaddress()])
+
+    def run_test(self):
+        self.default_wallet = self.nodes[0].get_wallet_rpc(self.default_wallet_name)
+        self.test_0_value_anchor_listunspent()
+        self.test_cannot_sign_anchors()
+
+if __name__ == '__main__':
+    WalletAnchorTest(__file__).main()