Fix MQTT v5 overlapping subscription behaviour.

Clients now receive message from all matching subscriptions rather than the first one encountered, which ensures the maximum QoS requirement is met.
eclipse · May 29, 2019 · 142d07f · 142d07f
1 parent de695af
commit 142d07f
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/ChangeLog.txt b/ChangeLog.txt
@@ -25,6 +25,9 @@ Broker:
 - Fix incorrect shared subscription topic '$shared'.
 - Fix zero length client ids being rejected for MQTT v5 clients with clean
  start set to true.
+- Fix MQTT v5 overlapping subscription behaviour. Clients now receive message
+ from all matching subscriptions rather than the first one encountered, which
+ ensures the maximum QoS requirement is met.
 
 Client library:
 - Fix typo causing build error on Windows when building without TLS support.

diff --git a/src/database.c b/src/database.c
@@ -364,7 +364,8 @@ int db__message_insert(struct mosquitto_db *db, struct mosquitto *context, uint1
  * multiple times for overlapping subscriptions, although this is only the
  * case for SUBSCRIPTION with multiple subs in so is a minor concern.
  */
- if(db->config->allow_duplicate_messages == false
+ if(context->protocol != mosq_p_mqtt5
+ && db->config->allow_duplicate_messages == false
  && dir == mosq_md_out && retain == false && stored->dest_ids){
 
  for(i=0; i<stored->dest_id_count; i++){