Swift Concurrency Guard

Overview

The Concurrency Guard is a SwiftSyntax-based static analyzer that blocks edits introducing concurrency anti-patterns. It runs as a Claude Code PreToolUse hook, preventing regressions before they happen.

Blocker Rules (Exit Code 2)

These rules block edits when violated. Claude receives the error and must fix the code.

CC-CONC-001 — No Task.detached

Why: Unstructured tasks cause priority inversions and are hard to cancel. SSE reconnection loops using Task.detached became unbounded/unowned.

Detect: Task.detached anywhere outside allowlisted paths.

Fix: Replace with structured Task {} owned by a lifecycle object; store handle + cancel.