Should the broker startup fail when a bridge is configured without topics, or is it acceptable to start the broker and simply ignore the invalid bridge configuration?

[DenvE]

In this function, no error is returned to the caller.

async fn setup_bridges(
config: &BrokerConfig,
router: &Arc,
) -> Option<Arc>

only returns:

Some(Arc) when bridges are configured
None when config.bridges is empty

There is no Result<T, E>, so errors cannot propagate upwards but are logged :

2026-07-09T14:13:45.937676Z INFO mqtt5::broker::server: Initializing 1 bridge(s)
2026-07-09T14:13:45.937699Z INFO mqtt5::broker::server: Adding bridge 'bridge'
2026-07-09T14:13:45.937716Z INFO mqtt5::broker::bridge::manager: Loop prevention initialized from bridge config ttl_secs=60 cache_size=10000
2026-07-09T14:13:45.937741Z ERROR mqtt5::broker::server: Failed to add bridge 'bridge': Configuration error: Configuration error: Bridge must have at least one topic mapping
2026-07-09T14:13:45.937837Z INFO mqtt5::broker::server: Starting MQTT broker

[fabracht]

Done

[DenvE]

for completeness see #106