Pumpkin-MC/Pumpkin · error

unexpected event

Error message

unexpected event

What it means

This panic fires in `FromIntoEvent::data_from_event` when an `Event` passed to `EntityRemoveEvent`'s converter carries any variant other than `Event::EntityRemoveEvent`. The trait bridges the WIT-generated `Event` enum to a specific event's typed `Data`, and the match arm expects the host/plugin dispatch layer to always pair the event type with its matching variant. Receiving a mismatched variant means the event dispatch plumbing violated that pairing invariant, so the library aborts rather than silently coerce wrong data.

Solutions

1. Verify the host and the pumpkin-plugin-api crate use matching versions so `EventType::EntityRemoveEvent` maps to `Event::EntityRemoveEvent`
2. Check the event dispatch/registration code routes only `EventType::EntityRemoveEvent` to `EntityRemoveEvent`'s converter
3. If writing a dispatcher, filter events by `EVENT_TYPE` before calling `data_from_event`
4. Replace the panic with a logged error or `Result` return to fail gracefully instead of aborting the plugin host

Example fix

// before
fn data_from_event(event: Event) -> Self::Data {
    match event {
        Event::EntityRemoveEvent(data) => data,
        _ => panic!("unexpected event"),
    }
}
// after
fn data_from_event(event: Event) -> Result<Self::Data, Event> {
    match event {
        Event::EntityRemoveEvent(data) => Ok(data),
        other => Err(other),
    }
}

if event.event_type() != EventType::EntityRemoveEvent {
    return; // skip: not an EntityRemoveEvent, do not feed to data_from_event
}

fn as_entity_remove(event: &Event) -> Option<&EntityRemoveEventData> {
    match event {
        Event::EntityRemoveEvent(data) => Some(data),
        _ => None,
    }
}

let data = std::panic::catch_unwind(|| EntityRemoveEvent::data_from_event(event))
    .unwrap_or_else(|_| { log::error!("event type mismatch for EntityRemoveEvent"); return; });

When it happens

Trigger: The only call path is `data_from_event` invoked (indirectly via `FromIntoEvent` helpers) with an `Event` whose variant is not `Event::EntityRemoveEvent` — i.e. the dispatch layer routed an event of a different type to the `EntityRemoveEvent` handler, typically when `EVENT_TYPE` tagging and the `Event` enum variant disagree (version skew between host and plugin API, or a hand-written dispatch that ignores `EventType`).

Common situations: Plugin compiled against one pumpkin-plugin-api version while the host emits an older/newer `Event` enum ordering; a custom event bus that forwards raw `Event` values without checking `EventType`; a refactored dispatcher that registers `EntityRemoveEvent` under the wrong `EventType` key.

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/68505a1233811b1f. Report an issue: GitHub.

Appendix: source

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

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

use super::super::FromIntoEvent;

/// An event that occurs when an entity is removed from the world.
pub struct EntityRemoveEvent;
impl FromIntoEvent for EntityRemoveEvent {
    const EVENT_TYPE: EventType = EventType::EntityRemoveEvent;
    type Data = EntityRemoveEventData;

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

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

View on GitHub (pinned to 8d4639e25a)