reservation: return FUNDING_STILL_SYNCING_BITCOIN if we might be missing funds.

This is useful, and also makes us pass the testsuite.

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

wallet/reservation.c

@@ -310,19 +310,22 @@ static struct command_result *json_fundpsbt(struct command *cmd,
 		}
 
 		/* If they said "all", we expect to run out of utxos. */
-		if (all) {
+		if (all && tal_count(utxos))
-			/* If we have none at all though, fail */
-			if (!tal_count(utxos))
-				return command_fail(cmd, FUND_CANNOT_AFFORD,
-						    "No available UTXOs");
 			break;
-		}
+
+		/* Since it's possible the lack of utxos is because we haven't
+		 * finished syncing yet, report a sync timing error first */
+		if (!topology_synced(cmd->ld->topology))
+			return command_fail(cmd,
+					    FUNDING_STILL_SYNCING_BITCOIN,
+					    "Cannot afford: still syncing with bitcoin network...");
 
 		return command_fail(cmd, FUND_CANNOT_AFFORD,
 				    "Could not afford %s using all %zu available UTXOs: %s short",
-				    type_to_string(tmpctx,
+				    all ? "all"
-						   struct amount_sat,
+				    : type_to_string(tmpctx,
-						   amount),
+						     struct amount_sat,
+						     amount),
 				    tal_count(utxos),
 				    all ? "all"
 				    : type_to_string(tmpctx,
@@ -334,11 +337,16 @@ static struct command_result *json_fundpsbt(struct command *cmd,
 		/* Anything above 0 is "excess" */
 		if (!inputs_sufficient(input, AMOUNT_SAT(0),
 				       *feerate_per_kw, *weight,
-				       &diff))
+				       &diff)) {
+			if (!topology_synced(cmd->ld->topology))
+				return command_fail(cmd,
+						    FUNDING_STILL_SYNCING_BITCOIN,
+						    "Cannot afford: still syncing with bitcoin network...");
 			return command_fail(cmd, FUND_CANNOT_AFFORD,
 					    "All %zu inputs could not afford"
 					    " fees",
 					    tal_count(utxos));
+		}
 	}
 
 	return finish_psbt(cmd, utxos, *feerate_per_kw, *weight, diff, *reserve,