invoice: Make msatoshi field nullable.

Note that the database itself has the field nullable (sqlite3
does not even have non-nullable columns) but our in-memory
structures did not.

lightningd/invoice.c

@@ -81,7 +81,8 @@ static void tell_waiter(struct command *cmd, const struct invoice *paid)
 	json_object_start(response, NULL);
 	json_add_string(response, "label", paid->label);
 	json_add_hex(response, "rhash", &paid->rhash, sizeof(paid->rhash));
-	json_add_u64(response, "msatoshi", paid->msatoshi);
+	if (paid->msatoshi)
+		json_add_u64(response, "msatoshi", *paid->msatoshi);
 	json_add_bool(response, "complete", paid->state == PAID);
 	if (paid->state == PAID)
 		json_add_u64(response, "pay_index", paid->pay_index);
@@ -196,8 +197,9 @@ static void json_invoice(struct command *cmd,
 
 	sha256(&invoice->rhash, invoice->r.r, sizeof(invoice->r.r));
 
-	if (!json_tok_u64(buffer, msatoshi, &invoice->msatoshi)
-	    || invoice->msatoshi == 0) {
+	invoice->msatoshi = tal(invoice, u64);
+	if (!json_tok_u64(buffer, msatoshi, invoice->msatoshi)
+	    || *invoice->msatoshi == 0) {
 		command_fail(cmd, "'%.*s' is not a valid positive number",
 			     msatoshi->end - msatoshi->start,
 			     buffer + msatoshi->start);
@@ -229,7 +231,7 @@ static void json_invoice(struct command *cmd,
 	wallet_invoice_save(cmd->ld->wallet, invoice);
 
 	/* Construct bolt11 string. */
-	b11 = new_bolt11(cmd, &invoice->msatoshi);
+	b11 = new_bolt11(cmd, invoice->msatoshi);
 	b11->chain = get_chainparams(cmd->ld);
 	b11->timestamp = time_now().ts.tv_sec;
 	b11->payment_hash = invoice->rhash;
@@ -257,7 +259,7 @@ static void json_invoice(struct command *cmd,
 	payment.payment_hash = invoice->rhash;
 	payment.destination = NULL;
 	payment.status = PAYMENT_PENDING;
-	payment.msatoshi = invoice->msatoshi;
+	payment.msatoshi = *invoice->msatoshi;
 	payment.timestamp = b11->timestamp;
 
 	if (!wallet_payment_add(cmd->ld->wallet, &payment)) {
@@ -300,7 +302,8 @@ static void json_add_invoices(struct json_result *response,
 		json_object_start(response, NULL);
 		json_add_string(response, "label", i->label);
 		json_add_hex(response, "rhash", &i->rhash, sizeof(i->rhash));
-		json_add_u64(response, "msatoshi", i->msatoshi);
+		if (i->msatoshi)
+			json_add_u64(response, "msatoshi", *i->msatoshi);
 		json_add_bool(response, "complete", i->state == PAID);
 		json_add_u64(response, "expiry_time", i->expiry_time);
 		json_object_end(response);
@@ -366,7 +369,8 @@ static void json_delinvoice(struct command *cmd,
 	json_object_start(response, NULL);
 	json_add_string(response, "label", i->label);
 	json_add_hex(response, "rhash", &i->rhash, sizeof(i->rhash));
-	json_add_u64(response, "msatoshi", i->msatoshi);
+	if (i->msatoshi)
+		json_add_u64(response, "msatoshi", *i->msatoshi);
 	json_object_end(response);
 
 	error = delete_invoice(cmd, cmd->ld->wallet, invs, i);

lightningd/invoice.h

@@ -21,7 +21,7 @@ struct invoice {
 	u64 id;
 	enum invoice_status state;
 	const char *label;
-	u64 msatoshi;
+	u64 *msatoshi;
 	struct preimage r;
 	u64 expiry_time;
 	struct sha256 rhash;

lightningd/peer_htlcs.c

@@ -269,10 +269,10 @@ static void handle_localpay(struct htlc_in *hin,
 	 *
 	 * 1. type: PERM|16 (`incorrect_payment_amount`)
 	 */
-	if (hin->msatoshi < invoice->msatoshi) {
+	if (invoice->msatoshi != NULL && hin->msatoshi < *invoice->msatoshi) {
 		failcode = WIRE_INCORRECT_PAYMENT_AMOUNT;
 		goto fail;
-	} else if (hin->msatoshi > invoice->msatoshi * 2) {
+	} else if (invoice->msatoshi != NULL && hin->msatoshi > *invoice->msatoshi * 2) {
 		failcode = WIRE_INCORRECT_PAYMENT_AMOUNT;
 		goto fail;
 	}

wallet/wallet.c

@@ -1236,7 +1236,11 @@ void wallet_invoice_save(struct wallet *wallet, struct invoice *inv)
 		sqlite3_bind_blob(stmt, 1, &inv->rhash, sizeof(inv->rhash), SQLITE_TRANSIENT);
 		sqlite3_bind_blob(stmt, 2, &inv->r, sizeof(inv->r), SQLITE_TRANSIENT);
 		sqlite3_bind_int(stmt, 3, inv->state);
-		sqlite3_bind_int64(stmt, 4, inv->msatoshi);
+		if (inv->msatoshi) {
+			sqlite3_bind_int64(stmt, 4, *inv->msatoshi);
+		} else {
+			sqlite3_bind_null(stmt, 4);
+		}
 		sqlite3_bind_text(stmt, 5, inv->label, strlen(inv->label), SQLITE_TRANSIENT);
 		sqlite3_bind_int64(stmt, 6, inv->expiry_time);
 		if (inv->state == PAID) {
@@ -1287,7 +1291,14 @@ static bool wallet_stmt2invoice(sqlite3_stmt *stmt, struct invoice *inv)
 	memcpy(&inv->rhash, sqlite3_column_blob(stmt, 3), sqlite3_column_bytes(stmt, 3));
 
 	inv->label = tal_strndup(inv, sqlite3_column_blob(stmt, 4), sqlite3_column_bytes(stmt, 4));
-	inv->msatoshi = sqlite3_column_int64(stmt, 5);
+
+	if (sqlite3_column_type(stmt, 5) != SQLITE_NULL) {
+		inv->msatoshi = tal(inv, u64);
+		*inv->msatoshi = sqlite3_column_int64(stmt, 5);
+	} else {
+		inv->msatoshi = NULL;
+	}
+
 	inv->expiry_time = sqlite3_column_int64(stmt, 6);
 	/* Correctly 0 if pay_index is NULL. */
 	inv->pay_index = sqlite3_column_int64(stmt, 7);