# WaitGroup Misuse

- ID: go-waitgroup-misuse
- Severity: HIGH
- CWE: Race Condition (CWE-362)
- Languages: Go

## Description

Improper use of sync.WaitGroup can cause race conditions, panics, or deadlocks.
Common issues include calling Add() inside goroutines and Done() count mismatches.

## Detection Message

Improper WaitGroup usage can cause:
- Race conditions (Add inside goroutine)
- Panics (negative counter from Done miscount)
- Deadlocks (Wait before Add completes)


## Remediation

1. Always Add() BEFORE starting goroutine:
```go
wg.Add(1)
go func() {
    defer wg.Done()
    // work
}()
```

2. Always use defer wg.Done() to ensure it runs:
```go
go func() {
    defer wg.Done()  // Runs even if panic occurs
    work()
}()
```

3. Consider using errgroup for better error handling:
```go
g, ctx := errgroup.WithContext(ctx)
g.Go(func() error {
    return work()
})
err := g.Wait()
```

## Documentation

[object Object]

## Related Rules

- **Concurrent Slice Access** [HIGH]: 
- **Direct Map Access on Thread-Safe Struct** [HIGH]: 
- **Potential Race Condition** [MEDIUM]: 
- **Race Condition in Concurrent Operations** [HIGH]: 
- **Potential Race Condition** [MEDIUM]: