objc-block-retain-cycles

What problem does it solve?

This Skill provides a systematic approach to diagnose and fix Objective-C block retain cycles, the leading cause of memory leaks, app crashes, and "sending message to deallocated instance" errors. It prevents silent memory accumulation and ensures app stability.

Core Features & Use Cases

• Systematic Diagnosis: Mandatory first steps using Instruments (Allocations, Memory Debugger) to confirm, trace, and understand retain cycles.
• Weak-Strong Pattern Enforcement: Detailed guidance on correctly applying the __weak typeof(self) weakSelf = self; and if (strongSelf) pattern to break cycles.
• Hidden Capture Detection: Identifies subtle self captures within macros (e.g., NSAssert, NSLog) and ensures proper guarding in nested blocks.
• Use Case: When a UIViewController isn't deallocating after being dismissed, use this skill to systematically check for self references in any blocks assigned to properties or network operations, then apply the weak-strong pattern to break the cycle.

Quick Start

To diagnose a suspected block retain cycle, first use Instruments' Allocations template to confirm memory isn't returning to baseline after dismissing a screen.