---

name: rxswift-memory-check description: Quick RxSwift memory leak detection for iOS. Finds missing dispose bags, retain cycles, and strong self references. Use when debugging memory issues, checking Observable subscriptions, or investigating retain cycles in RxSwift code. allowed-tools: Read, Grep, Glob

RxSwift Memory Leak Detector

Fast, focused check for RxSwift memory management issues in iOS code.

When to Activate

• "memory leak", "retain cycle", "dispose bag"
• "RxSwift memory issues", "check subscriptions"
• "[weak self]", "memory management"
• Debugging memory problems or crashes

Quick Check Process

Step 1: Find RxSwift Subscriptions

Use Grep to locate all Observable subscriptions:

• Pattern: \.subscribe\(
• Check surrounding code for proper disposal

Step 2: Verify Each Subscription

For every .subscribe(:

1. ✅ Has .disposed(by: disposeBag)
2. ✅ Uses [weak self] or [unowned self] in closures
3. ✅ DisposeBag is a property, not local variable

Step 3: Check Common Patterns

🔴 Pattern 1: Missing Disposal

CopyviewModel.data
    .subscribe(onNext: { data in })
    // MISSING: .disposed(by: disposeBag)

🔴 Pattern 2: Retain Cycle

CopyviewModel.data
    .subscribe(onNext: { data in
        self.updateUI(data)  // Strong self!
    })

🔴 Pattern 3: Local DisposeBag

Copyfunc loadData() {
    let disposeBag = DisposeBag()  // Local variable!
    // Cancels immediately when function ends
}

Step 4: Generate Report

Focused report with:

• Critical issues by severity
• File locations and line numbers
• Current vs. fixed code
• Impact assessment
• Recommended fixes

Search Patterns

Find subscriptions without disposal

CopyPattern: \.subscribe\(
Context: Check next 5 lines for .disposed

Find strong self references

CopyPattern: subscribe.*\{[^[]*self\.
Context: -A 3 -B 1

Find local DisposeBag declarations

CopyPattern: let disposeBag = DisposeBag\(\)

Output Format

Copy# RxSwift Memory Check Report

## Critical Issues: X

### 1. Missing Disposal - MEMORY LEAK
**File**: `PaymentViewModel.swift:45`
**Risk**: Memory accumulation, eventual crash

**Current**:
```swift
// Missing disposal

Fix:

Copy.disposed(by: disposeBag)

Impact: [Explanation]

---

Summary

🔴 Critical: X (memory leaks/retain cycles) ⚠️ Warnings: X (could use weak self)

Files Status

✅ Clean files ⚠️ Files with warnings 🔴 Files with critical issues

Copy
## DisposeBag Best Practices

✅ **Correct**: Property-level DisposeBag
```swift
class ViewModel {
    private let disposeBag = DisposeBag()
}

❌ Wrong: Local DisposeBag

Copyfunc loadData() {
    let disposeBag = DisposeBag()  // Cancels immediately!
}

When to Use weak vs unowned

• Default: Always use [weak self] (safer)
• Rare: Use [unowned self] only if 100% sure self outlives subscription

Quick Fix Guide

1. Add Missing Disposal: .disposed(by: disposeBag)
2. Add Weak Self: [weak self] in closure
3. Move DisposeBag: To property level

Testing the Fix

Suggest verification:

1. Run Instruments with Leaks template
2. Navigate to/from screens multiple times
3. Check Debug Memory Graph for cycles
4. Verify view controllers deallocate

Reference

Detailed Examples: See examples.md for extensive code samples and scenarios.