CoreCLR Migration Scanner

Unity is removing Mono in 6.8.

Unity calls the move to CoreCLR the most significant change to its C# layer in over a decade. Every commercial project has to audit for it, there is a hard deadline, and the official migration guidance is a forum thread. This is that audit, as a tool you run in the editor and in CI.

WHAT IT DOES

Scans every C# file and reflects over every compiled assembly in your project against a 22-rule corpus covering the five categories that break: serialization, threading, assembly loading, reflection and P/Invoke. Each finding tells you why CoreCLR breaks it and what to do about it - the part you cannot get from a grep.

THE COMPILED-ASSEMBLY HALF IS THE REASON TO BUY IT

A text search finds what you wrote. Your real exposure is usually in the plugins you bought, shipped as DLLs, whose vendors may be long gone. There is no source to search, so a source-only audit reports a clean project and you find out at runtime.

This detects platform-invoke methods in compiled assemblies using the CLR's own MethodAttributes.PinvokeImpl metadata flag. That is certainty rather than pattern matching, and it works whether or not the source exists anywhere on earth. Those findings are tagged [compiled assembly].

TRACK THE BURNDOWN

Save a baseline, and every later scan shows the delta against it. "-3 since baseline" is the number a producer reports upward. A cancelled scan is marked cancelled everywhere, because a partial scan finds fewer problems than a complete one and would otherwise read as progress.

CONTINUOUS INTEGRATION

Run it headless with -executeMethod CSAF.CoreCLRScanner.BatchMode.Run. It writes JSON and Markdown, fails the build on a breaking-count budget, and refuses to report a pass on an incomplete scan. Commit the JSON - the diff between two reports is the burndown.

WHAT IT DELIBERATELY DOES NOT DO

Unity ships Project Auditor free and bundled from 6.4 onward, covering domain-reload static state and, since 2.0.0, obsolete API. This does not reimplement either. Run both; they do not overlap. The included readme states the scope limits in full, including the known false negatives - a line-oriented rule carries no type information, and the assembly half reads metadata rather than method bodies.

VERIFIED

Unity 6000.5.7f1. Batch-mode compile with -warnaserror: 0 errors, 0 warnings. 52/52 EditMode tests green, run against a fresh install of the shipped package.

THIRD-PARTY NOTICES

This package contains no third-party assets: no fonts, images, audio, libraries or copied code. Each rule links to the vendor's own documentation (Microsoft Learn, Unity Discussions) for reference only, and those pages are not included. See Third-Party Notices.txt in the package for the full list.