Setting number of segments will disable notifications

[milenkovicm]

with latest moka 0.9.6 setting segments will disable notifications.

simple example to reproduce:

moka = { version = "0.9", features = [ "sync" ] }

use moka::sync::Cache;
use std::time::Duration;

#[tokio::main]
async fn main() {

    let notification_configuration = moka::notification::Configuration::builder()
        .delivery_mode(moka::notification::DeliveryMode::Queued)
        .build();

    let listener = move |key, _value, _cause|  {
        println!("--> {}", key)
    };

    let cache = Cache::builder()
        .time_to_idle(Duration::from_secs(3))
        .eviction_listener_with_conf(listener, notification_configuration)
        .name("tracked_sessions")
        .segments(1) 
        .build();


    cache.insert("key".to_string(), "value 0".to_string());
    cache.insert("key".to_string(), "value 1".to_string());
    cache.insert("key".to_string(), "value 2".to_string());
    tokio::time::sleep(Duration::from_secs(3)).await;
    cache.insert("key".to_string(), "value 3".to_string());
    tokio::time::sleep(Duration::from_secs(10)).await;    
}

Will print nothing, but removing .segments(1) will properly print/show four notifications.

at it looks, number of segments does not make difference.

[tatsuya6502]

Thank you for reporting the bug. This seems a simple mistake; calling segment method will reset the eviction listener, etc.

https://github.com/moka-rs/moka/blob/v0.9.6/src/sync/builder.rs#L117-L119

        CacheBuilder {
            name: self.name,
            max_capacity: self.max_capacity,
            initial_capacity: self.initial_capacity,
            num_segments: Some(num_segments),
            weigher: None,
            eviction_listener: None,  // <=
            eviction_listener_conf: None,

As a workaround, please call segment at the very beginning of the method chain:

let cache = Cache::builder()
        .segments(1)   // Move up to here.
        .time_to_idle(Duration::from_secs(3))
        .eviction_listener_with_conf(listener, notification_configuration)
        .name("tracked_sessions")
        .build();

[tatsuya6502]

Closing. This bug has been addressed by #215 for upcoming v0.9.7 release.