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Splice: Add splicein command #8856

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9559026
splice: Add splicein test
ddustin Jan 20, 2026
b0fb6fe
splice: Add documentation for splicein
ddustin Jan 20, 2026
b75c33c
Add splicein command
ddustin Jan 20, 2026
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67 changes: 67 additions & 0 deletions contrib/msggen/msggen/schema.json
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Expand Up @@ -33917,6 +33917,73 @@
}
]
},
"splicein.json": {
"$schema": "../rpc-schema-draft.json",
"type": "object",
"additionalProperties": false,
"added": "v26.04",
"rpc": "splicein",
"title": "Command to splice funds into a channel",
"warning": "experimental-splicing only",
"description": [
"`splicein` is the command to move funds into a channel."
],
"request": {
"required": [
"channel",
"amount"
],
"properties": {
"channel": {
"type": "string",
"description": [
"channel identifier or channel query. Format is the same as is used in `dev-splice`."
]
},
"amount": {
"type": "string",
"description": [
"Amount in satoshis taken from the internal wallet and add to the channel. Format is the same as is used in `dev-splice`."
]
}
}
},
"response": {
"required": [],
"properties": {
"psbt": {
"type": "string",
"description": [
"The final psbt"
]
},
"tx": {
"type": "string",
"description": [
"The final transaction in hex"
]
},
"txid": {
"type": "string",
"description": [
"The txid of the final transaction"
]
}
}
},
"usage": [
"`splicein` is the command to add funds to a channel. It takes `amount` funds from your onchain wallet and places them into `channel`."
],
"author": [
"Dusty [@dusty_daemon](mailto:@dustydaemon) is mainly responsible."
],
"see_also": [
"lightning-dev-splice(7)"
],
"resources": [
"Main web site: [https://github.com/ElementsProject/lightning](https://github.com/ElementsProject/lightning)"
]
},
"sql-template.json": {
"$schema": "../rpc-schema-draft.json",
"type": "object",
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8 changes: 8 additions & 0 deletions contrib/pyln-client/pyln/client/lightning.py
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Expand Up @@ -1226,6 +1226,14 @@ def splice(self, script_or_json, dryrun=None, force_feerate=None, debug_log=None
}
return self.call("dev-splice", payload)

def splicein(self, channel, amount):
""" Execute a splice """
payload = {
"channel": channel,
"amount": amount,
}
return self.call("splicein", payload)

def stfu_channels(self, channel_ids):
""" STFU multiple channels """
payload = {
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1 change: 1 addition & 0 deletions doc/Makefile
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Expand Up @@ -135,6 +135,7 @@ MARKDOWNPAGES := doc/addgossip.7 \
doc/signmessage.7 \
doc/signmessagewithkey.7 \
doc/signpsbt.7 \
doc/splicein.7 \
doc/splice_init.7 \
doc/splice_signed.7 \
doc/splice_update.7 \
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1 change: 1 addition & 0 deletions doc/index.rst
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Expand Up @@ -154,6 +154,7 @@ Core Lightning Documentation
splice_init <splice_init.7.md>
splice_signed <splice_signed.7.md>
splice_update <splice_update.7.md>
splicein <splicein.7.md>
sql <sql.7.md>
staticbackup <staticbackup.7.md>
stop <stop.7.md>
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67 changes: 67 additions & 0 deletions doc/schemas/splicein.json
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@@ -0,0 +1,67 @@
{
"$schema": "../rpc-schema-draft.json",
"type": "object",
"additionalProperties": false,
"added": "v26.04",
"rpc": "splicein",
"title": "Command to splice funds into a channel",
"warning": "experimental-splicing only",
"description": [
"`splicein` is the command to move funds into a channel."
],
"request": {
"required": [
"channel",
"amount"
],
"properties": {
"channel": {
"type": "string",
"description": [
"channel identifier or channel query. Format is the same as is used in `dev-splice`."
]
},
"amount": {
"type": "string",
"description": [
"Amount in satoshis taken from the internal wallet and add to the channel. Format is the same as is used in `dev-splice`."
]
}
}
},
"response": {
"required": [],
"properties": {
"psbt": {
"type": "string",
"description": [
"The final psbt"
]
},
"tx": {
"type": "string",
"description": [
"The final transaction in hex"
]
},
"txid": {
"type": "string",
"description": [
"The txid of the final transaction"
]
}
}
},
"usage": [
"`splicein` is the command to add funds to a channel. It takes `amount` funds from your onchain wallet and places them into `channel`."
],
"author": [
"Dusty [@dusty_daemon](mailto:@dustydaemon) is mainly responsible."
],
"see_also": [
"lightning-dev-splice(7)"
],
"resources": [
"Main web site: [https://github.com/ElementsProject/lightning](https://github.com/ElementsProject/lightning)"
]
}
46 changes: 46 additions & 0 deletions plugins/spender/splice.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1462,10 +1462,56 @@ json_splice(struct command *cmd, const char *buf, const jsmntok_t *params)
return send_outreq(req);
}

static struct command_result *
json_splicein(struct command *cmd, const char *buf, const jsmntok_t *params)
{
struct out_req *req;
const char *channel, *amount;
struct splice_cmd *splice_cmd;
char *script;

if (!param(cmd, buf, params,
p_req("channel", param_string, &channel),
p_req("amount", param_string, &amount),
NULL))
return command_param_failed();

script = tal_fmt(NULL,
"wallet -> %s + fee; %s -> %s",
amount, channel, amount);

splice_cmd = tal(cmd, struct splice_cmd);

splice_cmd->cmd = cmd;
splice_cmd->script = tal_steal(splice_cmd, script);
splice_cmd->psbt = create_psbt(splice_cmd, 0, 0, 0);
splice_cmd->dryrun = false;
splice_cmd->wetrun = false;
splice_cmd->feerate_per_kw = 0;
splice_cmd->force_feerate = false;
splice_cmd->wallet_inputs_to_signed = 0;
splice_cmd->fee_calculated = false;
splice_cmd->initial_funds = AMOUNT_SAT(0);
splice_cmd->emergency_sat = AMOUNT_SAT(0);
splice_cmd->debug_log = NULL;
splice_cmd->debug_counter = 0;
memset(&splice_cmd->final_txid, 0, sizeof(splice_cmd->final_txid));

req = jsonrpc_request_start(cmd, "listpeerchannels",
listpeerchannels_get_result,
splice_error, splice_cmd);

return send_outreq(req);
}

const struct plugin_command splice_commands[] = {
{
"dev-splice",
json_splice
},
{
"splicein",
json_splicein
},
};
const size_t num_splice_commands = ARRAY_SIZE(splice_commands);
39 changes: 39 additions & 0 deletions tests/test_splice.py
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Expand Up @@ -195,3 +195,42 @@ def test_script_splice_in(node_factory, bitcoind, chainparams):
l1.wait_for_channel_onchain(l2.info['id'])
account_info = only_one([acct for acct in l1.rpc.bkpr_listbalances()['accounts'] if acct['account'] == account_id])
assert not account_info['account_closed']


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

coin_mvt_plugin = Path(__file__).parent / "plugins" / "coin_movements.py"
l1, l2 = node_factory.line_graph(2, fundamount=fundamt, wait_for_announce=True,
opts={'experimental-splicing': None,
'plugin': coin_mvt_plugin})

# Splice in 100k sats into first channel
spliceamt = 100000

l1.rpc.splicein("*:?", f"{spliceamt}")
p1 = only_one(l1.rpc.listpeerchannels(peer_id=l2.info['id'])['channels'])
p2 = only_one(l2.rpc.listpeerchannels(l1.info['id'])['channels'])
assert p1['inflight'][0]['splice_amount'] == spliceamt
assert p1['inflight'][0]['total_funding_msat'] == (fundamt + spliceamt) * 1000
assert p1['inflight'][0]['our_funding_msat'] == fundamt * 1000
assert p2['inflight'][0]['splice_amount'] == 0
assert p2['inflight'][0]['total_funding_msat'] == (fundamt + spliceamt) * 1000
assert p2['inflight'][0]['our_funding_msat'] == 0
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 p1['to_us_msat'] == (fundamt + spliceamt) * 1000
assert p1['total_msat'] == (fundamt + spliceamt) * 1000
assert p2['to_us_msat'] == 0
assert p2['total_msat'] == (fundamt + spliceamt) * 1000
assert 'inflight' not in p1
assert 'inflight' not in p2

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