refactor-migrate

name	refactor-migrate
description	Migrate dependencies, frameworks, or runtime versions with minimal breakage. Use this skill when upgrading libraries, switching frameworks, replacing deprecated APIs, bumping language/runtime versions, or says things like '升级依赖', '迁移到新版本', '替换废弃 API', 'upgrade to v4', 'migrate from X to Y', 'replace deprecated calls', 'bump Node/Python/Go version', 'framework migration', or 'dependency upgrade'. Also trigger when handling breaking changes from a version bump.
metadata	{"author":"QuentinHsu","version":"2026.04.05"}

Refactor Migrate

Upgrade dependencies, replace deprecated APIs, and adapt to new framework or runtime versions — applicable to any language or project.

Detailed rules live in:

• rules/dependency-upgrade.md
• rules/api-replacement.md
• rules/compatibility.md

Core Principle

A migration changes external interfaces (library calls, runtime behavior) while keeping the application's observable business behavior intact. Every step must be verifiable independently.

When To Use

Use this skill when the task involves:

• upgrading a library or framework to a new major/minor version
• replacing deprecated APIs with their recommended successors
• bumping language or runtime version (Node, Python, Go, Java, etc.)
• switching from one library to a competing alternative (e.g., Moment → date-fns, Request → fetch)
• adapting code to breaking changes introduced by an upstream update
• removing polyfills or compatibility shims that are no longer needed after a version bump

Working Mode

1. Inventory. List current versions of the targets being migrated. Identify the target versions. Read changelogs and migration guides.
2. Assess impact. Search the codebase for all usage sites of the APIs, configs, or features that change. Quantify scope (file count, call count).
3. Plan migration order. Dependencies have dependencies — upgrade leaf dependencies first, then work inward. Identify which changes can be done independently.
4. Apply dependency upgrade rules. Update version specifiers, lock files, and configuration. See rules/dependency-upgrade.md.
5. Apply API replacement rules. Replace deprecated or removed calls with new equivalents. See rules/api-replacement.md.
6. Apply compatibility rules. Handle behavioral changes, type changes, and edge cases across versions. See rules/compatibility.md.
7. Verify. Build, lint, and run existing tests. Flag any test failures caused by the migration.

Boundaries

• Do not change business logic during migration. Separate feature work from migration work.
• Do not upgrade unrelated dependencies in the same pass — scope to what the user asked.
• Do not remove a dependency without confirming zero remaining usage.
• Do not downgrade type safety or error handling to satisfy a new API.
• Prefer incremental migration (codemods, adapter layers) over big-bang rewrites when the change surface is large.

Default Output Expectations

• Show before/after for each API replacement.
• Note behavioral differences between old and new versions when they exist.
• Warn when a breaking change has no direct equivalent and a workaround is needed.
• When the migration is large, produce a step-by-step plan before writing code.