[Contract] — Feature: Add `cancel_event` entrypoint (creator-only)

[Olowodarey]

Background

The Event struct already has cancel() method, is_cancelled: bool field,
and several downstream functions (e.g. create_match, join_event) guard
against cancelled events. The error code EventError::EventCancelled is also
defined.

Goal

Add cancel_event(env, caller, event_id) that marks an event as cancelled
(only the event creator may do this, only before finalization).

Tasks

1. Add EventError::AlreadyFinalized (if not already present) and
2. Add pub fn cancel_event(env: &Env, caller: Address, event_id: u64) -> Result<(), EventError> in src/event.rs:
3. Wire into lib.rs:
4. Add tests in a new tests/cancel_event_tests.rs:

Acceptance Criteria

• Only the event creator can cancel; cancellation is irreversible.
• Cancelled events block joins, match creation, and predictions.
• A contract event ("event", "cancelled") is emitted on success.

Files

contracts/creator-event-manager/src/event.rs,
contracts/creator-event-manager/src/lib.rs,
contracts/creator-event-manager/tests/cancel_event_tests.rs,

[David-Adegboyega]

@David-Adegboyega has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @David-Adegboyega to this issue.

[Babigdk]

@Babigdk has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I’d like to work on this issue.

I will implement a "cancel_event" entrypoint in "src/event.rs" that allows only the event creator to cancel an event before finalization. The function will enforce proper authorization checks, ensure cancellation is irreversible, and block all downstream actions such as joins, match creation, and predictions for cancelled events.

I will also add the required error handling (including "EventError::AlreadyFinalized" where applicable), wire the function into "lib.rs", emit a ""event", "cancelled"" contract event on success, and create comprehensive tests in "tests/cancel_event_tests.rs" to validate access control, state transitions, and system-wide blocking behavior.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Babigdk to this issue.

[Awointa]

@Awointa has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I’m interested in this issue. I have experience implementing access-controlled entrypoints and state transitions in Soroban contracts.

I can add cancel_event with proper creator-only authorization, enforce pre-finalization checks, wire it into lib.rs, emit the cancellation event, and add tests covering authorization, irreversibility, and downstream blocking behavior.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Awointa to this issue.

[drips-wave]

Congratulations, @Awointa! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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