Pumpkin-MC/Pumpkin · error

unexpected event

Error message

unexpected event

What it means

This panic fires inside `data_from_event` for EntityDismountEvent when the incoming `Event` is not `Event::EntityDismountEvent`. The function exists to unwrap the generic `Event` enum into the concrete `EntityDismountEventData`; the catch-all arm treats any other variant as an impossible state, because the dispatcher contract guarantees only matching variants are delivered. Hitting it means event routing delivered a mismatched payload.

Solutions

1. Verify the event is routed/dispatched as `Event::EntityDismountEvent` before reaching `data_from_event`
2. In manual dispatch code, match on the variant yourself or check `event_type()` equals `EventType::EntityDismountEvent` first
3. Align plugin-api versions across server and plugin so the `Event` enum layout is identical
4. Soften the catch-all to return a `Result`/log instead of panicking if robustness matters more than strictness

Example fix

// before
match event {
    Event::EntityDeathEvent(d) => <EntityDismountEvent as Event>::data_from_event(Event::EntityDeathEvent(d)),
    _ => unreachable!(),
}
// after
match event {
    Event::EntityDismountEvent(d) => <EntityDismountEvent as Event>::data_from_event(Event::EntityDismountEvent(d)),
    _ => unreachable!(),
}

if !matches!(event, Event::EntityDismountEvent(_)) { return; }
<crate::events::entity::entity_dismount::EntityDismountEvent as Event>::data_from_event(event);

fn as_entity_dismount(event: &Event) -> Option<&EntityDismountEventData> {
    match event { Event::EntityDismountEvent(d) => Some(d), _ => None }
}

// guard before unwrapping:
if let Event::EntityDismountEvent(data) = event {
    // use data
} else {
    log::error!("misrouted event: expected EntityDismountEvent");
}

When it happens

Trigger: Invoking the `Event` trait's `data_from_event` with any variant other than `Event::EntityDismountEvent` — manual dispatch with the wrong variant, a dispatcher that pairs `EventType::EntityDismountEvent` with the wrong data, or test harness code feeding arbitrary events through the wrong implementation.

Common situations: Copy-pasted dispatch code in tests using a neighboring event variant; custom event-bus code that stores `Event` values and forwards them without checking `EVENT_TYPE`; version skew between plugin-api crates where variant names drifted.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• unexpected event
• unexpected event
• unexpected event
• unexpected event
• unexpected event

AI-assisted analysis of Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/b922c533501f5daf. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-plugin-api/src/events/entity/entity_dismount.rs:14

use crate::wit::pumpkin::plugin::event::{EntityDismountEventData, Event, EventType};

use super::super::FromIntoEvent;

/// Event triggered when an entity dismounts another entity.
pub struct EntityDismountEvent;
impl FromIntoEvent for EntityDismountEvent {
    const EVENT_TYPE: EventType = EventType::EntityDismountEvent;
    type Data = EntityDismountEventData;

    fn data_from_event(event: Event) -> Self::Data {
        match event {
            Event::EntityDismountEvent(data) => data,
            _ => panic!("unexpected event"),
        }
    }

    fn data_into_event(data: Self::Data) -> Event {
        Event::EntityDismountEvent(data)
    }
}

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