# StateError: Bad state: Cannot add event while adding another event

- **ID:** `flutter/state-error-bloc-event-handler`
- **Domain:** flutter
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 88%

## Root Cause

Attempting to call bloc.add() from within an event handler of the same Bloc instance, causing a reentrant call.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| flutter 3.16 | active | — | — |
| flutter 3.22 | active | — | — |
| bloc 8.0.0 | active | — | — |
| flutter_bloc 8.1.0 | active | — | — |

## Workarounds

1. **Use a separate isolate or schedule the new event outside the current handler using Future.microtask(() => bloc.add(Event())). This ensures the current event processing completes before the new event is added.** (90% success)
   ```
   Use a separate isolate or schedule the new event outside the current handler using Future.microtask(() => bloc.add(Event())). This ensures the current event processing completes before the new event is added.
   ```
2. **Restructure the Bloc logic to combine both operations into a single event or use async gaps like await Future.delayed(Duration.zero) before calling bloc.add().** (85% success)
   ```
   Restructure the Bloc logic to combine both operations into a single event or use async gaps like await Future.delayed(Duration.zero) before calling bloc.add().
   ```

## Dead Ends

- **Adding a short delay with Future.delayed before bloc.add()** — Delay does not prevent the reentrant call from the same synchronous context; the error still occurs if the logic is in the same event handler chain. (85% fail)
- **Wrapping bloc.add() in a try-catch block** — The StateError is thrown synchronously and cannot be caught inside the event handler because Bloc internally throws it before the catch block is reached. (75% fail)