Pumpkin-MC/Pumpkin · error

unexpected event

Error message

unexpected event

What it means

This panic fires in `data_from_event`, the `Event` trait implementation for `FurnaceSmeltEvent`. It matches only `Event::FurnaceSmeltEvent(data)`; any other `Event` variant means the dispatcher sent a wrong-type payload to the smelting handler. The library considers this a broken dispatch invariant and panics with "unexpected event".

Solutions

1. Register the handler for `EventType::FurnaceSmeltEvent` so dispatch only sends that variant.
2. Use `FurnaceSmeltEvent::data_into_event(data)` when constructing events for manual calls.
3. Synchronize versions and clean-rebuild the workspace to fix `Event` enum mismatch.
4. Check the variant first: `if let Event::FurnaceSmeltEvent(data) = event { ... }`.
5. Replace the panic with a logged error or typed failure for graceful handling.

Example fix

// before
match event {
    Event::FurnaceSmeltEvent(data) => data,
    _ => panic!("unexpected event"),
}
// after
match event {
    Event::FurnaceSmeltEvent(data) => data,
    _ => log::error!("FurnaceSmeltEvent handler received unexpected variant"),
    _ => return None,
}

// Before dispatch
assert_eq!(event.event_type(), EventType::FurnaceSmeltEvent, "wrong event routed to FurnaceSmelt handler");

fn as_furnace_smelt(event: &Event) -> Option<&FurnaceSmeltEventData> {
    match event {
        Event::FurnaceSmeltEvent(data) => Some(data),
        _ => None,
    }
}

let result = std::panic::catch_unwind(AssertUnwindSafe(|| handler.data_from_event(event)));
if result.is_err() {
    log::error!("FurnaceSmeltEvent handler received an unexpected event variant");
}

When it happens

Trigger: Dispatching a non-`FurnaceSmeltEvent` variant (e.g. `FurnaceBurnEvent`) to this handler's `data_from_event`, or registering the handler under a mismatched `EventType`.

Common situations: Handler registration tables that conflate furnace events, hand-written routing, or enum drift after upgrading pumpkin-plugin-api so the match arm no longer receives the expected variant.

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/5d0777a45abbab8a. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-plugin-api/src/events/inventory/furnace_smelt.rs:13

use super::super::FromIntoEvent;
use crate::wit::pumpkin::plugin::event::{Event, EventType, FurnaceSmeltEventData};

/// Event triggered when an item is smelted in a furnace.
pub struct FurnaceSmeltEvent;
impl FromIntoEvent for FurnaceSmeltEvent {
    const EVENT_TYPE: EventType = EventType::FurnaceSmeltEvent;
    type Data = FurnaceSmeltEventData;

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

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

View on GitHub (pinned to 8d4639e25a)