Serialization Migration Guard

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Unity serialization migrations fail silently. Everything looks fine until someone opens a scene or prefab later and values are gone. Unity Serialization Migration Guard is like a smoke alarm for refactors: it forces you to prove your rename is safe before you delete anything.

If a single broken migration costs you 4 to 8 hours of debugging and manual cleanup, this pays for itself the first time you use it.

Is this tool for you?

• You renamed a serialized field and do not fully trust that every asset updated
• You are adding [FormerlySerializedAs] and want to catch anything you missed
• You want a real coverage report, not guesswork
• You need a repeatable migration workflow for teams and CI

How it works

1. Audit your rename mappings and get clear risk warnings before you touch assets
2. Coverage Scan searches text-serialized YAML for legacy field tokens and produces a ranked report
3. Reserialize only the right assets, with a preview first and optional backups
4. Cleanup Proof tells you when it is safe to remove legacy mappings and old paths

What you get

• Git diff import that suggests rename mappings from unified diffs (preview, append, or replace)
• Audit warnings that matter, including missing types, ambiguous type names, missing target fields, non-serializable target fields, and missing [FormerlySerializedAs]
• Coverage reporting with counts per field and per asset, plus unreadable asset tracking
• Guided reserialize with preview, progress, cancellation, and optional backups (asset + .meta)
• Exports to JSON and CSV for audit, coverage, and cleanup reports
• Batchmode + CI gates with commands and exit codes so you can fail builds when risk remains

Supported asset scope

• Scenes (.unity)
• Prefabs (.prefab)
• ScriptableObject assets (.asset), including parent assets with embedded ScriptableObjects

Requirements and notes

• Coverage scan and cleanup proof require Project Settings -> Editor -> Asset Serialization Mode = Force Text
• Coverage is token based. If multiple fields share the same token name, results can be ambiguous
• Unsupported asset types are skipped and shown as skipped inputs