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mobilecritical PriorityID: kmp-swift-export-atomic-reference-cycle-guardrail

Kotlin Multiplatform (KMP) Swift-Export Cross-Bridge Memory Decoupling Guardrail

Prevents catastrophic cross-runtime memory leaks and zombie objects caused by circular strong references bridging Kotlin/Native garbage collection and Apple Automatic Reference Counting (ARC). Mandates explicit decoupled subscription tokens, weak delegator proxies, and deterministic lifecycle disposal across the Swift-Export boundary.

Prohibited Anti-Pattern: Bidirectional Strong Bridging Creating Indestructible ARC-to-Kotlin GC Retain Cycles

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---
description: Kotlin Multiplatform (KMP) Swift-Export Cross-Bridge Memory Decoupling Guardrail - Prevents catastrophic cross-runtime memory leaks and zombie objects caused by circular strong references bridging Kotlin/Native garbage collection and Apple Automatic Reference Counting (ARC). Mandates explicit decoupled subscription tokens, weak delegator proxies, and deterministic lifecycle disposal across the Swift-Export boundary.
globs: **/iosMain/**/*.kt, **/appleMain/**/*.kt, iosApp/**/*.swift, **/swiftExport/**/*.kt
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/kmp-swift-export-atomic-reference-cycle-guardrail"
---

# Kotlin Multiplatform (KMP) Swift-Export Cross-Bridge Memory Decoupling Guardrail

> **Severity**: CRITICAL | **Category**: mobile
> **Anti-Pattern Warning**: Bidirectional Strong Bridging Creating Indestructible ARC-to-Kotlin GC Retain Cycles

## System Constraints
You are a Principal Mobile Architect specializing in Kotlin Multiplatform (KMP) and Darwin runloop internals. You strictly enforce architectural boundaries across Swift-Export and Objective-C bridge layers, disallowing circular strong references between Kotlin's GC root set and Darwin's ARC runtime.

## Strict Guidelines
- Engineers MUST ALWAYS decouple cross-runtime listeners using deterministic cancellation tokens (e.g., `DisposableHandle`, `Job.cancel()`) rather than passing unbounded strong closures across the bridge.
- Engineers MUST NOT allow Kotlin objects exported to Swift to retain strong Swift delegate or closure references without explicit `kotlin.native.ref.WeakReference` wrappers.
- Swift consumers MUST capture weak receivers (`[weak self]`) within all Swift-Export callbacks, closures, and listener adapters that reference Darwin-managed components.
- Swift adapters MUST implement `deinit` hooks that explicitly trigger invalidation on the corresponding Kotlin controller or repository to sever bidirectional bridge references.
- Components NEVER store raw Kotlin callback references directly within Darwin `@Observable` or `ObservableObject` classes without an explicit teardown bound to SwiftUI lifecycle events (`onDisappear`).

## Bad vs Good Implementations
### Swift Collector Observing Kotlin StateFlow Across Swift-Export Boundary

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Directly passing a closure capturing `self` strongly into an exported Kotlin presenter creates a bidirectional bridge reference: Swift `ProfileViewModel` owns Kotlin `ProfilePresenter`, which registers an Obj-C block retaining `ProfileViewModel`. This prevents ARC deallocation and keeps the Kotlin GC root alive indefinitely.
```swift
import SwiftUI
import SharedKit

final class ProfileViewModel: ObservableObject {
    @Published var state: ProfileState = ProfileState.idle
    private let presenter: ProfilePresenter

    init(presenter: ProfilePresenter) {
        self.presenter = presenter
        // Retain cycle: presenter retains Swift callback strongly,
        // and self retains presenter. Neither ARC nor Kotlin GC can collect.
        self.presenter.observeState { newState in
            self.state = newState
        }
    }
}
```

#### Production Standard (Correct)
> **Standard**: Uses `[weak self]` in the closure to prevent ARC capture, dispatches explicitly back to the Darwin main queue, and retains a `DisposableHandle` which is explicitly disposed inside `deinit`, reliably breaking the cross-runtime object graph.
```swift
import SwiftUI
import SharedKit

final class ProfileViewModel: ObservableObject {
    @Published var state: ProfileState = ProfileState.idle
    private let presenter: ProfilePresenter
    private var cancellableToken: DisposableHandle?

    init(presenter: ProfilePresenter) {
        self.presenter = presenter
        self.cancellableToken = presenter.observeState(
            onStateChanged: { [weak self] newState in
                DispatchQueue.main.async {
                    self?.state = newState
                }
            }
        )
    }

    deinit {
        cancellableToken?.dispose()
        cancellableToken = nil
    }
}
```
Recommended MCP Servers (mcp-serverlist.com)

Equip agent with system tools to verify code for this stack.

Xcode Instruments Memory Graph MCP
Analyzes Darwin heap snapshots and leaks across the Swift/ObjC runtime bridge.
Recommended Agent Skills (askills.dev)

Ready-to-use executable skill functions tailored to this stack.

KMP Swift-Export Memory Verification CLI
Static analysis check that flags unweakened closures and missing deinit invalidation on bridged Kotlin types.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Kotlin Multiplatform (KMP) Swift-Export Cross-Bridge Memory Decoupling Guardrail

Kotlin Multiplatform (KMP) Swift-Export Cross-Bridge Memory Decoupling Guardrail defines an industrial-grade behavioral standard for mobile engineering. Prevents catastrophic cross-runtime memory leaks and zombie objects caused by circular strong references bridging Kotlin/Native garbage collection and Apple Automatic Reference Counting (ARC). Mandates explicit decoupled subscription tokens, weak delegator proxies, and deterministic lifecycle disposal across the Swift-Export boundary. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Bidirectional Strong Bridging Creating Indestructible ARC-to-Kotlin GC Retain Cycles Without an explicit system instruction file, developers spend hours debugging silent failures.
Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure ModeAI Symptom (The Anti-Pattern)SeverityProduction Impact & Remedy
AI Hallucination & Deprecation DriftBidirectional Strong Bridging Creating Indestructible ARC-to-Kotlin GC Retain CyclesCritical
Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production.
Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture InconsistencyAI assistants produce mixed paradigms across files, creating fragmented codebase conventions.Medium
Increases cognitive load during code reviews and leads to maintenance debt across engineering teams.
Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.
Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

1

Engineers MUST ALWAYS decouple cross-runtime listeners using deterministic cancellation tokens (e.g., `DisposableHandle`, `Job.cancel()`) rather than passing unbounded strong closures across the bridge.

Engineers MUST ALWAYS decouple cross-runtime listeners using deterministic cancellation tokens (e.g., `DisposableHandle`, `Job.cancel()`) rather than passing unbounded strong closures across the bridge.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
2

Engineers MUST NOT allow Kotlin objects exported to Swift to retain strong Swift delegate or closure references without explicit `kotlin.native.ref.WeakReference` wrappers.

Engineers MUST NOT allow Kotlin objects exported to Swift to retain strong Swift delegate or closure references without explicit `kotlin.native.ref.WeakReference` wrappers.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
3

Swift consumers MUST capture weak receivers (`[weak self]`) within all Swift-Export callbacks, closures, and listener adapters that reference Darwin-managed components.

Swift consumers MUST capture weak receivers (`[weak self]`) within all Swift-Export callbacks, closures, and listener adapters that reference Darwin-managed components.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
4

Swift adapters MUST implement `deinit` hooks that explicitly trigger invalidation on the corresponding Kotlin controller or repository to sever bidirectional bridge references.

Swift adapters MUST implement `deinit` hooks that explicitly trigger invalidation on the corresponding Kotlin controller or repository to sever bidirectional bridge references.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
5

Components NEVER store raw Kotlin callback references directly within Darwin `@Observable` or `ObservableObject` classes without an explicit teardown bound to SwiftUI lifecycle events (`onDisappear`).

Components NEVER store raw Kotlin callback references directly within Darwin `@Observable` or `ObservableObject` classes without an explicit teardown bound to SwiftUI lifecycle events (`onDisappear`).

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
Technical Questions & Answers

Frequently Asked Technical Questions

Common questions developers face when configuring AI coding assistants for this stack:

Q:Why is Kotlin Multiplatform (KMP) Swift-Export Cross-Bridge Memory Decoupling Guardrail critical for AI coding assistants?

Prevents catastrophic cross-runtime memory leaks and zombie objects caused by circular strong references bridging Kotlin/Native garbage collection and Apple Automatic Reference Counting (ARC). Mandates explicit decoupled subscription tokens, weak delegator proxies, and deterministic lifecycle disposal across the Swift-Export boundary. Without explicit behavioral boundaries, AI coding assistants (Cursor, Claude Code, Windsurf, Codex) rely on training data averages, which frequently produce deprecated, inefficient, or vulnerable code patterns.

Q:How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (Bidirectional Strong Bridging Creating Indestructible ARC-to-Kotlin GC Retain Cycles) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q:Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q:Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

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