bug-fix

What problem does it solve? Fixing bugs without understanding the root cause leads to symptom-masking patches, regressions, and repeated failures. This Skill enforces a disciplined bug-fixing workflow: reproduce or gather evidence first, locate the root cause using a four-part structure (symptom, cause analysis, fix plan, affected files), verify with compilation and tests, then commit following repository conventions. ## Core Features & Use Cases - Root-Cause-First Workflow: Structures diagnosis as symptom → cause → fix plan → affected files, forbidding symptom masking like swallowed exceptions or loosened validation. - Evidence-Based Diagnosis: Supports runtime reproduction via logs (trace_id), database state checks (production read-only), static forensics for non-reproducible defects, and full-scope enumeration when evidence comes from samples or screenshots. - Mandatory Verification and Commit: Runs project build and test commands after changes, classifies failures as newly introduced vs pre-existing, and produces conventional Chinese commit messages with explicit git add. - Use Case: A user reports a 500 error with a trace_id on an order API. The Skill pulls logs, traces the call chain, identifies the null-state root cause, applies a minimal fix, runs the module's unit tests, and commits with a structured fix message. ## Quick Start Use the bug-fix skill to diagnose and fix this bug: the order submission endpoint returns a 500 error with trace_id abc123 when the cart is empty.