Fix QoS 0 messages not being delivered when max_queued_bytes was configured.

Closes #2123. Thanks to quackgizmo.

ChangeLog.txt

@@ -5,6 +5,8 @@ Broker:
 - Fix `tls_version` behaviour not matching documentation. It was setting the
   exact TLS version to use, not the minimium TLS version to use. Closes #2110.
 - Fix messages to `$` prefixed topics being rejected. Closes #2111.
+- Fix QoS 0 messages not being delivered when max_queued_bytes was configured.
+  Closes #2123.
 
 
 2.0.8 - 2021-02-25

lib/mosquitto_internal.h

@@ -190,8 +190,8 @@ struct mosquitto_msg_data{
 #ifdef WITH_BROKER
 	struct mosquitto_client_msg *inflight;
 	struct mosquitto_client_msg *queued;
-	unsigned long msg_bytes;
-	unsigned long msg_bytes12;
+	long msg_bytes;
+	long msg_bytes12;
 	int msg_count;
 	int msg_count12;
 #else

src/database.c

@@ -53,7 +53,7 @@ bool db__ready_for_flight(struct mosquitto_msg_data *msgs, int qos)
 		if(db.config->max_queued_messages == 0 && db.config->max_inflight_bytes == 0){
 			return true;
 		}
-		valid_bytes = msgs->msg_bytes - db.config->max_inflight_bytes < db.config->max_queued_bytes;
+		valid_bytes = ((msgs->msg_bytes - (ssize_t)db.config->max_inflight_bytes) < (ssize_t)db.config->max_queued_bytes);
 		valid_count = msgs->msg_count - msgs->inflight_maximum < db.config->max_queued_messages;
 
 		if(db.config->max_queued_messages == 0){
@@ -90,8 +90,8 @@ bool db__ready_for_queue(struct mosquitto *context, int qos, struct mosquitto_ms
 {
 	int source_count;
 	int adjust_count;
-	size_t source_bytes;
-	size_t adjust_bytes = db.config->max_inflight_bytes;
+	long source_bytes;
+	ssize_t adjust_bytes = (ssize_t)db.config->max_inflight_bytes;
 	bool valid_bytes;
 	bool valid_count;
 

test/broker/02-subpub-qos0-queued-bytes.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+from mosq_test_helper import *
+
+def write_config(filename, port):
+    with open(filename, 'w') as f:
+        f.write("listener %d\n" % (port))
+        f.write("allow_anonymous true\n")
+        f.write("max_inflight_messages 20\n")
+        f.write("max_inflight_bytes 1000000\n")
+        f.write("max_queued_messages 20\n")
+        f.write("max_queued_bytes 1000000\n")
+
+def do_test(proto_ver):
+    rc = 1
+    keepalive = 60
+    connect_packet = mosq_test.gen_connect("subpub-qos0-bytes", keepalive=keepalive, proto_ver=proto_ver)
+    connack_packet = mosq_test.gen_connack(rc=0, proto_ver=proto_ver)
+
+    connect_packet_helper = mosq_test.gen_connect("qos0-bytes-helper", keepalive=keepalive, proto_ver=proto_ver)
+
+    mid = 1
+    subscribe_packet = mosq_test.gen_subscribe(mid, "subpub/qos0/queued/bytes", 1, proto_ver=proto_ver)
+    suback_packet = mosq_test.gen_suback(mid, 1, proto_ver=proto_ver)
+
+    publish_packet0 = mosq_test.gen_publish("subpub/qos0/queued/bytes", qos=0, payload="message", proto_ver=proto_ver)
+
+
+    port = mosq_test.get_port()
+    conf_file = os.path.basename(__file__).replace('.py', '.conf')
+    write_config(conf_file, port)
+    broker = mosq_test.start_broker(filename=os.path.basename(__file__), use_conf=True, port=port)
+
+    try:
+        sock = mosq_test.do_client_connect(connect_packet, connack_packet, timeout=4, port=port, connack_error="connack 1")
+
+        mosq_test.do_send_receive(sock, subscribe_packet, suback_packet, "suback")
+
+        helper = mosq_test.do_client_connect(connect_packet_helper, connack_packet, timeout=4, port=port, connack_error="connack helper")
+
+        helper.send(publish_packet0)
+        mosq_test.expect_packet(sock, "publish0", publish_packet0)
+        rc = 0
+
+        sock.close()
+    except mosq_test.TestError:
+        pass
+    finally:
+        os.remove(conf_file)
+        broker.terminate()
+        broker.wait()
+        (stdo, stde) = broker.communicate()
+        if rc:
+            print(stde.decode('utf-8'))
+            print("proto_ver=%d" % (proto_ver))
+            exit(rc)
+
+
+do_test(proto_ver=4)
+do_test(proto_ver=5)
+exit(0)

test/broker/Makefile

@@ -45,6 +45,7 @@ test : test-compile 01 02 03 04 05 06 07 08 09 10 11 12 13 14
 	./02-subhier-crash.py
 	./02-subpub-qos0-long-topic.py
 	./02-subpub-qos0-oversize-payload.py
+	./02-subpub-qos0-queued-bytes.py
 	./02-subpub-qos0-retain-as-publish.py
 	./02-subpub-qos0-send-retain.py
 	./02-subpub-qos0-subscription-id.py

test/broker/test.py

@@ -28,6 +28,7 @@ tests = [
     (1, './02-subhier-crash.py'),
     (1, './02-subpub-qos0-long-topic.py'),
     (1, './02-subpub-qos0-oversize-payload.py'),
+    (1, './02-subpub-qos0-queued-bytes.py'),
     (1, './02-subpub-qos0-retain-as-publish.py'),
     (1, './02-subpub-qos0-send-retain.py'),
     (1, './02-subpub-qos0-subscription-id.py'),