lightningd: handle fail_htlc_in with no known outgoing channel.

Turn it into temporary node failure: this only happens if we restart
with a failed htlc in, but it's clearer and more robust to handle it
generically.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/peer_htlcs.c

@@ -109,8 +109,16 @@ static void fail_in_htlc(struct htlc_in *hin,
 		hin->failonion = dup_onionreply(hin, failonion);
 
 	/* We need this set, since we send it to channeld. */
-	if (hin->failcode & UPDATE)
-		hin->failoutchannel = *out_channelid;
+	if (hin->failcode & UPDATE) {
+		/* We don't save the outgoing channel which failed; probably
+		 * not worth it for this corner case.  So we can't set
+		 * hin->failoutchannel to tell channeld what update to send,
+		 * thus we turn those into a WIRE_TEMPORARY_NODE_FAILURE. */
+		if (!out_channelid)
+			hin->failcode = WIRE_TEMPORARY_NODE_FAILURE;
+		else
+			hin->failoutchannel = *out_channelid;
+	}
 
 	/* We update state now to signal it's in progress, for persistence. */
 	htlc_in_update_state(hin->key.channel, hin, SENT_REMOVE_HTLC);
@@ -2167,6 +2175,7 @@ static const struct json_command dev_ignore_htlcs = {
 	"Set ignoring incoming HTLCs for peer {id} to {ignore}", false,
 	"Set/unset ignoring of all incoming HTLCs.  For testing only."
 };
+
 AUTODATA(json_command, &dev_ignore_htlcs);
 #endif /* DEVELOPER */
 

wallet/wallet.c

@@ -1904,13 +1904,6 @@ static bool wallet_stmt2htlc_out(struct wallet *wallet,
 
 static void fixup_hin(struct wallet *wallet, struct htlc_in *hin)
 {
-	/* We don't save the outgoing channel which failed; probably not worth
-	 * it for this corner case.  So we can't set hin->failoutchannel to
-	 * tell channeld what update to send, thus we turn those into a
-	 * WIRE_TEMPORARY_NODE_FAILURE. */
-	if (hin->failcode & UPDATE)
-		hin->failcode = WIRE_TEMPORARY_NODE_FAILURE;
-
 	/* We didn't used to save failcore, failonion... */
 #ifdef COMPAT_V061
 	/* We care about HTLCs being removed only, not those being added. */