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splicescript: Turn on bitcoin addresses in splice script #8991

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6aa09d2
splicescript: Add test for splice out to btc addr
ddustin Mar 25, 2026
33b6782
splicescript: Fix rare memleak of aborting an abort
ddustin Mar 25, 2026
c9b4ac4
splicescript: Fix bugs in bitcoin addr handling
ddustin Mar 25, 2026
574e859
splicescript: Turn on bitcoin addresses in splice script
ddustin Mar 25, 2026
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159 changes: 90 additions & 69 deletions plugins/spender/splice.c
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,16 @@ static struct command_result *unreserve_get_result(struct command *cmd,
return make_error(cmd, abort_pkg, "unreserve_get_result");
}

static struct command_result *free_abort_pkg_and_forward(struct command *cmd,
const char *methodname,
const char *buf,
const jsmntok_t *result,
struct abort_pkg *abort_pkg)
{
tal_free(abort_pkg);
return forward_error(cmd, methodname, buf, result, NULL);
}

static struct command_result *abort_get_result(struct command *cmd,
const char *methodname,
const char *buf,
Expand All @@ -163,7 +173,8 @@ static struct command_result *abort_get_result(struct command *cmd,
return make_error(cmd, abort_pkg, "abort_get_result");

req = jsonrpc_request_start(cmd, "unreserveinputs",
unreserve_get_result, forward_error,
unreserve_get_result,
free_abort_pkg_and_forward,
abort_pkg);

json_add_psbt(req->js, "psbt", splice_cmd->psbt);
Expand Down Expand Up @@ -193,7 +204,9 @@ static struct command_result *do_fail(struct command *cmd,
abort_pkg->code = code;

req = jsonrpc_request_start(cmd, "abort_channels",
abort_get_result, forward_error, abort_pkg);
abort_get_result,
free_abort_pkg_and_forward,
abort_pkg);

added = 0;
json_array_start(req->js, "channel_ids");
Expand Down Expand Up @@ -1620,6 +1633,77 @@ static struct command_result *handle_fee_and_ppm(struct command *cmd,
return NULL;
}

/* Fund out to bitcoin addresses */
static struct command_result *handle_bitcoin_addrs(struct command *cmd,
struct splice_cmd *splice_cmd)
{
struct splice_script_result *action;
struct splice_cmd_action_state *state;
struct wally_psbt_output *output;
char *bitcoin_address;
u64 serial_id;
u8 *scriptpubkey;

for (size_t i = 0; i < tal_count(splice_cmd->actions); i++) {
action = splice_cmd->actions[i];
state = splice_cmd->states[i];
if (!action->bitcoin_address)
continue;
if (state->state != SPLICE_CMD_NONE)
continue;

if (!amount_sat_is_zero(action->out_sat))
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Cannot fund from bitcoin"
" address");
if (!decode_scriptpubkey_from_addr(cmd, chainparams,
action->bitcoin_address,
&scriptpubkey))
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Bitcoin address"
" unrecognized");

/* Reencode scriptpubkey to addr for verification */
bitcoin_address = encode_scriptpubkey_to_addr(tmpctx,
chainparams,
scriptpubkey,
tal_bytelen(scriptpubkey));
if (!bitcoin_address)
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Bitcoin scriptpubkey failed"
" reencoding for address");

if (0 != strcmp(bitcoin_address, action->bitcoin_address))
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
tal_fmt(tmpctx,
"Bitcoin scriptpubkey"
" failed validation for"
" address. Reencoded"
" address is %s while"
" address from script is"
" %s",
bitcoin_address ?: "NULL",
action->bitcoin_address));

output = psbt_append_output(splice_cmd->psbt,
scriptpubkey,
action->in_sat);

serial_id = psbt_new_output_serial(splice_cmd->psbt,
TX_INITIATOR);
psbt_output_set_serial_id(splice_cmd->psbt, output,
serial_id);

state->state = SPLICE_CMD_DONE;
}

return NULL;
}

static struct command_result *continue_splice(struct command *cmd,
struct splice_cmd *splice_cmd)
{
Expand Down Expand Up @@ -1661,6 +1745,10 @@ static struct command_result *continue_splice(struct command *cmd,
splice_cmd->fee_calculated = true;
}

result = handle_bitcoin_addrs(cmd, splice_cmd);
if (result)
return result;

/* Only after fee calcualtion can we add wallet actions taking funds */
for (size_t i = 0; i < tal_count(splice_cmd->actions); i++) {
action = splice_cmd->actions[i];
Expand Down Expand Up @@ -1762,18 +1850,13 @@ static struct command_result *execute_splice(struct command *cmd,
struct splice_cmd *splice_cmd)
{
struct splice_script_result *action;
struct splice_cmd_action_state *state;
struct wally_psbt_output *output;
u64 serial_id;
int pays_fee;
u8 *scriptpubkey;

/* Basic validation */
pays_fee = 0;
for (size_t i = 0; i < tal_count(splice_cmd->actions); i++) {
int dest_count = 0;
action = splice_cmd->actions[i];
state = splice_cmd->states[i];

if (action->out_ppm && !action->onchain_wallet)
return do_fail(cmd, splice_cmd, JSONRPC2_INVALID_PARAMS,
Expand Down Expand Up @@ -1824,8 +1907,6 @@ static struct command_result *execute_splice(struct command *cmd,

for (size_t i = 0; i < tal_count(splice_cmd->actions); i++) {
action = splice_cmd->actions[i];
state = splice_cmd->states[i];
char *bitcoin_address;

/* `out_ppm` is the percent to take out of the action.
* If it is set to '*' we get a value of UINT32_MAX.
Expand All @@ -1842,61 +1923,11 @@ static struct command_result *execute_splice(struct command *cmd,
" feerate");
splice_cmd->feerate_per_kw = action->feerate_per_kw;
}

/* Fund out to bitcoin address */
if (action->bitcoin_address) {
if (!amount_sat_is_zero(action->in_sat))
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Cannot fund from bitcoin"
" address");
if (!decode_scriptpubkey_from_addr(cmd, chainparams,
action->bitcoin_address,
&scriptpubkey))
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Bitcoin address"
" unrecognized");

/* Reencode scriptpubkey to addr for verification */
bitcoin_address = encode_scriptpubkey_to_addr(tmpctx,
chainparams,
scriptpubkey,
tal_bytelen(scriptpubkey));
if (!bitcoin_address)
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Bitcoin scriptpubkey failed"
" reencoding for address");

if (!strcmp(bitcoin_address, action->bitcoin_address))
return do_fail(cmd, splice_cmd,
JSONRPC2_INVALID_PARAMS,
"Bitcoin scriptpubkey failed"
" validation for address");

output = psbt_append_output(splice_cmd->psbt,
scriptpubkey,
action->in_sat);

/* DTODO: support dynamic address payouts (percent) */

serial_id = psbt_new_output_serial(splice_cmd->psbt,
TX_INITIATOR);
psbt_output_set_serial_id(splice_cmd->psbt, output,
serial_id);

state->state = SPLICE_CMD_DONE;

add_to_debug_log(splice_cmd,
"execute_splice-load_btcaddress");
}
}

/* Set needed funds to the wallet contributions. */
for (size_t i = 0; i < tal_count(splice_cmd->actions); i++) {
action = splice_cmd->actions[i];
state = splice_cmd->states[i];
if (action->onchain_wallet
&& !amount_sat_is_zero(action->out_sat)) {
splice_cmd->needed_funds = action->out_sat;
Expand Down Expand Up @@ -2042,16 +2073,6 @@ validate_splice_cmd(struct splice_cmd *splice_cmd)
" fee");
paying_fee_count++;
}
if (action->bitcoin_address && action->in_ppm)

@Andezion Andezion Jul 22, 2026

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Nice! No remaining guard exists, but none is needed

return command_fail(splice_cmd->cmd,
JSONRPC2_INVALID_PARAMS,
"Dynamic bitcoin address amounts"
" not supported for now");
if (action->bitcoin_address)
return command_fail(splice_cmd->cmd,
JSONRPC2_INVALID_PARAMS,
"Paying out to bitcoin addresses"
" not supported for now.");
}

return NULL;
Expand Down
33 changes: 32 additions & 1 deletion tests/test_splice.py
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Original file line number Diff line number Diff line change
Expand Up @@ -653,7 +653,38 @@ def test_easy_splice_out(node_factory, bitcoind, chainparams):
assert initial_wallet_balance + Millisatoshi(spliceamt * 1000) == end_wallet_balance


@pytest.mark.xfail(strict=True)

@Andezion Andezion Jul 22, 2026

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The xfail(strict=True) removal from test_splice_out_address is correct, but the test only covers a fixed absolute amount to the address - the percent-based path enabled by point 4 (in_ppm -> address) is now reachable code but has zero test coverage?

@pytest.mark.openchannel('v1')
@pytest.mark.openchannel('v2')
@unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
def test_splice_out_address(node_factory, bitcoind, chainparams):
fundamt = 1000000

l1, l2 = node_factory.line_graph(2, fundamount=fundamt, wait_for_announce=True,
opts={'experimental-splicing': None})

initial_wallet_balance = Millisatoshi(bkpr_account_balance(l1, 'wallet'))

addr = l1.rpc.newaddr()['p2tr']

# Splice out 100k from first channel, putting result less fees into onchain wallet via addres
spliceamt = 100000
l1.rpc.splice(f"*:? -> {spliceamt}+fee; {spliceamt} -> {addr}")

bitcoind.generate_block(6, wait_for_mempool=1)
l2.daemon.wait_for_log(r'lightningd, splice_locked clearing inflights')

p1 = only_one(l1.rpc.listpeerchannels(peer_id=l2.info['id'])['channels'])
p2 = only_one(l2.rpc.listpeerchannels(l1.info['id'])['channels'])
assert 'inflight' not in p1
assert 'inflight' not in p2

wait_for(lambda: len(l1.rpc.listfunds()['outputs']) == 2)
wait_for(lambda: len(l1.rpc.listfunds()['channels']) == 1)

end_wallet_balance = Millisatoshi(bkpr_account_balance(l1, 'wallet'))
assert initial_wallet_balance + Millisatoshi(spliceamt * 1000) == end_wallet_balance


@pytest.mark.openchannel('v1')
@pytest.mark.openchannel('v2')
@unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
Expand Down
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