df-tests: patch for state == AWAITING_UNILATERAL problem

Found on CI where DEVELOPER=0 EXPERIMENTAL_DUAL_FUND=1,
as we turn off automatic reconnects when DEVELOPER=1

This test has been modified to make the error happen every time, and
then fixed.

lightningd-2: 2021-05-07T20:12:03.790Z DEBUG   0266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c03518-chan#1: Peer has reconnected, state AWAITING_UNILATERAL
lightningd-2: 2021-05-07T20:12:03.812Z **BROKEN** lightningd: FATAL SIGNAL 6 (version e8b3f78)
lightningd-2: 2021-05-07T20:12:03.812Z **BROKEN** lightningd: backtrace: common/daemon.c:44 (send_backtrace) 0x56384ee072e9
lightningd-2: 2021-05-07T20:12:03.813Z **BROKEN** lightningd: backtrace: common/daemon.c:52 (crashdump) 0x56384ee0733b

----------------------------- Captured stderr call -----------------------------
lightningd: lightningd/peer_control.c:1100: peer_connected_hook_final: Assertion `channel->state == DUALOPEND_OPEN_INIT || channel->state == DUALOPEND_AWAITING_LOCKIN' failed.
lightningd: FATAL SIGNAL 6 (version e8b3f78)
0x56384ee072a1 send_backtrace
	common/daemon.c:39
0x56384ee0733b crashdump
	common/daemon.c:52
0x7f88486a020f ???
	???:0
0x7f88486a018b ???
	???:0
0x7f884867f858 ???
	???:0
0x7f884867f728 ???
	???:0
0x7f8848690f35 ???
	???:0
0x56384eddc94e peer_connected_hook_final
	lightningd/peer_control.c:1100
0x56384edea2ed plugin_hook_call_
	lightningd/plugin_hook.c:275
0x56384eddfeb8 plugin_hook_call_peer_connected
	lightningd/peer_control.c:1156
0x56384eddfeb8 peer_connected
	lightningd/peer_control.c:1209
0x56384edc30cd connectd_msg
	lightningd/connect_control.c:332
0x56384edebe6f sd_msg_read
	lightningd/subd.c:509
0x56384edebfb1 read_fds
	lightningd/subd.c:310
0x56384ee483b0 next_plan
	ccan/ccan/io/io.c:59
0x56384ee4885b do_plan
	ccan/ccan/io/io.c:407
0x56384ee488f8 io_ready
	ccan/ccan/io/io.c:417
0x56384ee4a23c io_loop
	ccan/ccan/io/poll.c:445
0x56384edcabda io_loop_with_timers
	lightningd/io_loop_with_timers.c:24
0x56384edce826 main
	lightningd/lightningd.c:1111
0x7f88486810b2 ???
	???:0
0x56384edb52ad ???
	???:0
0xffffffffffffffff ???
	???:0

lightningd/peer_control.c

@@ -1093,12 +1093,11 @@ static void peer_connected_hook_final(struct peer_connected_hook_payload *payloa
 	if (feature_negotiated(ld->our_features,
 			       peer->their_features,
 			       OPT_DUAL_FUND)) {
-		/* if we have a channel, we're actually restarting
-		 * dualopend. we only get here if there's an error  */
 		if (channel) {
 			assert(!channel->owner);
 			assert(channel->state == DUALOPEND_OPEN_INIT
-			       || channel->state == DUALOPEND_AWAITING_LOCKIN);
+			       || channel->state == DUALOPEND_AWAITING_LOCKIN
+			       || channel->state == AWAITING_UNILATERAL);
 			channel->peer->addr = addr;
 			channel->peer->connected_incoming = payload->incoming;
 			peer_restart_dualopend(peer, payload->pps, channel, error);

tests/test_plugin.py

@@ -9,7 +9,8 @@
     DEVELOPER, only_one, sync_blockheight, TIMEOUT, wait_for, TEST_NETWORK,
     DEPRECATED_APIS, expected_peer_features, expected_node_features,
     expected_channel_features, account_balance,
-    check_coin_moves, first_channel_id, check_coin_moves_idx, EXPERIMENTAL_FEATURES
+    check_coin_moves, first_channel_id, check_coin_moves_idx,
+    EXPERIMENTAL_FEATURES, EXPERIMENTAL_DUAL_FUND
 )
 
 import ast
@@ -846,6 +847,9 @@ def test_channel_state_changed_unilateral(node_factory, bitcoind):
     # such errors a soft because LND.
     opts = {"plugin": os.path.join(os.getcwd(), "tests/plugins/misc_notifications.py"),
             "allow_warning": True}
+    if EXPERIMENTAL_DUAL_FUND:
+        opts['may_reconnect'] = True
+
     l1, l2 = node_factory.line_graph(2, opts=opts)
 
     l1_id = l1.rpc.getinfo()["id"]
@@ -901,6 +905,9 @@ def wait_for_event(node):
     wait_for(lambda: len(l1.rpc.listpeers()['peers']) == 1)
     # check 'closer' on l2 while the peer is not yet forgotten
     assert(l2.rpc.listpeers()['peers'][0]['channels'][0]['closer'] == 'local')
+    if EXPERIMENTAL_DUAL_FUND:
+        l1.daemon.wait_for_log(r'Peer has reconnected, state')
+        l2.daemon.wait_for_log(r'Peer has reconnected, state')
 
     # settle the channel closure
     bitcoind.generate_block(100)