fix(mqtt): make the MQTT client-id unique per connection#5755
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jamesarich merged 1 commit intoJun 9, 2026
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The proxy/probe client-id was "MeshtasticAndroidMqttProxy-$myId", where
myId is the node id and is null ("unknown") until the local node record
loads. That is not unique per client: clients sharing a node id — and the
whole "unknown" pool on the public broker — present identical client-ids.
A broker evicts the previous holder (SESSION_TAKEN_OVER) when a duplicate
id connects, producing the reconnect storms behind the top io.ktor
TLS-write crash on 2.7.14.
Append a per-connection random Uuid suffix at each MqttClient/probe
construction (captured for the client's lifetime, so auto-reconnects stay
stable; a replacement client after a flap gets a fresh id). cleanStart is
true, so no durable session is lost.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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What
Append a per-connection random
Uuidsuffix to the MQTT proxy/probe client-id.Why
The client-id was
MeshtasticAndroidMqttProxy-$myId(and…Probe-$myId), wheremyIdis the node id — and isnull→ the literalunknownuntil the local node record loads. That isn't unique per connecting client:MeshtasticAndroidMqttProxy-unknown, so on the public broker they continuously evict one another.When a duplicate client-id connects, the broker evicts the previous holder with
SESSION_TAKEN_OVER(0x8E); the two clients take the session back and forth — a reconnect storm. That storm is the trigger for the topio.ktorTLS-write crash on 2.7.14 (fixed independently in themqtt-clientlibrary — this removes the trigger).A radio only accepts one app connection at a time, so there is never a legitimate case for two clients to share an id — making a unique suffix unambiguously safe.
Change
MQTTRepositoryImpl(proxy) andMqttManagerImpl(probe): append-${Uuid.random()}to the client-id. Generated once perMqttClient/probe construction, so the id is captured for that client's lifetime — auto-reconnects keep the same id (no self-eviction), while a brand-new client after a flap gets a fresh one.cleanStart = true(unchanged default), so there is no durable session to preserve — a per-connection id is fine and avoids a stable broker-trackable identifier.MQTTRepositoryImplTest: assert the client-id prefix instead of exact equality.Testing
spotlessCheck detekt kmpSmokeCompile :core:network:allTests :core:data:allTestsall pass.🤖 Generated with Claude Code