lightningd/opening_control: deprecate old fundchannel_complete args.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Deprecated: JSON-RPC: `fundchannel_complete` txid and txout parameters (use psbt)

doc/lightning-fundchannel_complete.7.md

@@ -4,7 +4,7 @@ lightning-fundchannel\_complete -- Command for completing channel establishment
 SYNOPSIS
 --------
 
-**fundchannel\_complete** *id* *txid* *txout*
+**fundchannel\_complete** *id* *psbt*
 
 DESCRIPTION
 -----------
@@ -14,9 +14,8 @@ complete an initiated channel establishment with a connected peer.
 
 *id* is the node id of the remote peer.
 
-*txid* is the hex string of the funding transaction id.
-
-*txout* is the integer outpoint of the funding output for this channel.
+*psbt* is the transaction to use for funding (does not need to be
+signed but must be otherwise complete).
 
 Note that the funding transaction MUST NOT be broadcast until after
 channel establishment has been successfully completed, as the commitment
@@ -37,6 +36,7 @@ with `code` being one of the following:
 - -1: Catchall nonspecific error.
 - 305: Peer is not connected.
 - 306: Unknown peer id.
+- 309: PSBT does not have a unique, correct output to fund the channel.
 
 AUTHOR
 ------

lightningd/opening_control.c

@@ -965,7 +965,7 @@ static struct command_result *json_fundchannel_complete(struct command *cmd,
 	bool old_api;
 
 	/* params is NULL for initial parameter desc generation! */
-	if (params /* FIXME: && deprecated_apis */) {
+	if (params && deprecated_apis) {
 		/* We used to have a three-arg version. */
 		if (params->type == JSMN_ARRAY)
 			old_api = (params->size == 3);

plugins/spender/multifundchannel.c

@@ -683,10 +683,7 @@ fundchannel_complete_dest(struct multifundchannel_destination *dest)
 				    &fundchannel_complete_err,
 				    dest);
 	json_add_node_id(req->js, "id", &dest->id);
-	json_add_string(req->js, "txid",
-			type_to_string(tmpctx, struct bitcoin_txid,
-				       mfc->txid));
-	json_add_num(req->js, "txout", dest->outnum);
+	json_add_psbt(req->js, "psbt", mfc->psbt);
 
 	send_outreq(cmd->plugin, req);
 }