dualfund: error on out of order sigs

We weren't blocking if the tx-sigs arrived before the commitment sigs.

This was causing problems in the openchannel (spender plugin)

spenderp: FATAL SIGNAL 11 (version v23.08.1-404-g62ff475-modded)
0x559836dc98ba send_backtrace
	common/daemon.c:33
0x559836dc9951 crashdump
	common/daemon.c:75
0x7f37f42c351f ???
	./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
0x7f37f441ac92 ???
	../sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S:83
0x559836db7760 bitcoin_txid_eq
	./bitcoin/tx.h:29
0x559836db7760 collect_sigs
	plugins/spender/openchannel.c:509
0x559836db81de check_sigs_ready
	plugins/spender/openchannel.c:531
0x559836db84dd json_peer_sigs
	plugins/spender/openchannel.c:611
0x559836dbcad7 ld_command_handle
	plugins/libplugin.c:1611
0x559836dbcd9d ld_read_json_one
	plugins/libplugin.c:1721
0x559836dbce29 ld_read_json
	plugins/libplugin.c:1741
0x559836ef3bff next_plan
	ccan/ccan/io/io.c:59
0x559836ef40da do_plan
	ccan/ccan/io/io.c:407
0x559836ef4177 io_ready
	ccan/ccan/io/io.c:417
0x559836ef5b14 io_loop
	ccan/ccan/io/poll.c:453
0x559836dbd48d plugin_main
	plugins/libplugin.c:1948
0x559836db22bf main
	plugins/spender/main.c:35
0x7f37f42aad8f __libc_start_call_main
	../sysdeps/nptl/libc_start_call_main.h:58
0x7f37f42aae3f __libc_start_main_impl
	../csu/libc-start.c:392
0x559836da3774 ???
	???:0
0xffffffffffffffff ???
	???:0
2023-10-31T15:15:57.458Z INFO    plugin-spenderp: Killing plugin: exited during normal operation
2023-10-31T15:15:57.458Z **BROKEN** plugin-spenderp: Plugin marked as important, shutting down lightningd!
2023-10-31T15:15:57.458Z DEBUG   lightningd: io_break: lightningd_exit
2023-10-31T15:15:57.458Z DEBUG   lightningd: io_loop_with_timers: main
2023-10-31T15:15:57.458Z DEBUG   connectd: REPLY WIRE_CONNECTD_START_SHUTDOWN_REPLY with 0 fds
2023-10-31T15:15:57.458Z DEBUG   lightningd: io_break: connectd_start_shutdown_reply
2023-10-31T15:15:57.458Z DEBUG   021ccce7bc396996c8f3b7bfeb1e30c6600269517026a74adfe2217b7187879797-dualopend-chan#1: Status closed, but not exited. Killing
2023-10-31T15:15:57.458Z DEBUG   lightningd: Command returned result after jcon close
2023-10-31T15:15:57.458Z INFO    021ccce7bc396996c8f3b7bfeb1e30c6600269517026a74adfe2217b7187879797-chan#1: Unsaved peer failed. Deleting channel.
2023-10-31T15:15:57.464Z DEBUG   lightningd: io_break: destroy_plugin
2023-10-31T15:15:57.464Z DEBUG   connectd: Shutting down
2023-10-31T15:15:57.464Z DEBUG   gossipd: Shutting down
2023-10-31T15:15:57.464Z DEBUG   hsmd: Shutting down

Reported-By: @t-bast

openingd/dualopend.c

@@ -1252,6 +1252,7 @@ static char *do_commit_signed_received(const tal_t *ctx,
 					     tx_state->psbt));
 	}
 
+	tx_state->has_commitments = true;
 	return NULL;
 }
 
@@ -1345,6 +1346,11 @@ static void handle_tx_sigs(struct state *state, const u8 *msg)
 					     struct bitcoin_txid,
 					     &tx_state->funding.txid));
 
+	if (!tx_state->has_commitments)
+		open_err_fatal(state,
+			      "tx_signatures sent before commitment sigs %s",
+			      tal_hex(msg, msg));
+
 	/* We put the PSBT + sigs all together */
 	for (size_t i = 0, j = 0; i < tx_state->psbt->num_inputs; i++) {
 		struct wally_psbt_input *in =

tests/test_opening.py

@@ -217,7 +217,6 @@ def test_v2_open_sigs_reconnect_1(node_factory, bitcoind):
 
 
 @unittest.skipIf(TEST_NETWORK != 'regtest', 'elementsd doesnt yet support PSBT features we need')
-@pytest.mark.xfail
 @pytest.mark.openchannel('v2')
 def test_v2_open_sigs_out_of_order(node_factory, bitcoind):
     """ Test what happens if the tx-sigs get sent "before" commitment signed """