From 14eddb95bae30dd9d95de6a3c0008a17a896b6d8 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Wed, 26 May 2021 10:49:38 +0930
Subject: [PATCH] fundchannel, multifundchannel: reserve inputs for two weeks,
 not 12 hours.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: Plugins: `fundchannel` and `multifundchannel` will now reserve funding they use for 2 weeks instead of 12 hours.
---
 plugins/spender/multifundchannel.c | 14 ++++++++++++--
 tests/test_connection.py           | 11 ++++++-----
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/plugins/spender/multifundchannel.c b/plugins/spender/multifundchannel.c
index 3ce71b8bd1b6..72fbe4e8cacf 100644
--- a/plugins/spender/multifundchannel.c
+++ b/plugins/spender/multifundchannel.c
@@ -205,6 +205,7 @@ mfc_cleanup_psbt(struct command *cmd,
 	}
 
 	json_add_psbt(req->js, "psbt", take(pruned_psbt));
+	json_add_u32(req->js, "reserve", 2016);
 	send_outreq(cmd->plugin, req);
 }
 
@@ -651,6 +652,9 @@ after_signpsbt(struct command *cmd,
 				    &mfc_forward_error,
 				    mfc);
 	json_add_psbt(req->js, "psbt", mfc->psbt);
+	/* We already reserved inputs by 2 weeks, we don't need
+	 * another 72 blocks. */
+	json_add_u32(req->js, "reserve", 0);
 	return send_outreq(mfc->cmd->plugin, req);
 }
 
@@ -1405,8 +1409,14 @@ perform_fundpsbt(struct multifundchannel_command *mfc)
 		json_add_u32(req->js, "minconf", mfc->minconf);
 	}
 
-	/* The entire point is to reserve the inputs.  */
-	json_add_bool(req->js, "reserve", true);
+	/* The entire point is to reserve the inputs. */
+	/*  BOLT #2:
+	 * The sender:
+	 *...
+	 *     - SHOULD ensure the funding transaction confirms in the next 2016
+	 *       blocks.
+	 */
+	json_add_u32(req->js, "reserve", 2016);
 	/* How much do we need to reserve?  */
 	if (has_all(mfc))
 		json_add_string(req->js, "satoshi", "all");
diff --git a/tests/test_connection.py b/tests/test_connection.py
index a67de1899537..a44103d2933b 100644
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -260,11 +260,12 @@ def test_channel_abandon(node_factory, bitcoind):
     opening_utxo = only_one([o for o in l1.rpc.listfunds()['outputs'] if o['reserved']])
     psbt = l1.rpc.utxopsbt(0, "253perkw", 0, [opening_utxo['txid'] + ':' + str(opening_utxo['output'])], reserve=False, reservedok=True)['psbt']
 
-    # Unreserve until it's considered unreserved.
-    count = 0
-    while only_one(l1.rpc.unreserveinputs(psbt)['reservations'])['reserved']:
-        count += 1
-    assert count == 1
+    # We expect a reservation for 2016 blocks; unreserve it.
+    reservations = only_one(l1.rpc.unreserveinputs(psbt, reserve=2015)['reservations'])
+    assert reservations['reserved']
+    assert reservations['reserved_to_block'] == bitcoind.rpc.getblockchaininfo()['blocks'] + 1
+
+    assert only_one(l1.rpc.unreserveinputs(psbt, reserve=1)['reservations'])['reserved'] is False
 
     # Now it's unreserved, we can doublespend it (as long as we exceed
     # previous fee to RBF!).