Polyfill

Latest release	0.9.26
Download	GitHub · Thunderstore
Requires	MelonLoader 0.7.3
Help	Discord · Report a bug

🛟 Need help or found a bug? support.doodesch.de/polyfill

Your old mods stopped working after a Schedule I update? Polyfill gets a lot of them running again.

⚠ Early beta

Still got a mod that will not run? Open the console, type polyfillexport, and send me the file it creates: support.doodesch.de/polyfill

The game gets an update. Mods made before it stop working. Polyfill patches the game so they run again.

It patches the game, not your mods. Your own files are never changed, and polyfillrestore takes the patch back out.

It cannot save every mod. The console tells you which ones.

Tested on

T.H.M - The Hitman Mod 5.0.2	runs
OverTheCounter Dispensary 2.0.10	runs; 29 of 40 names repaired, and two doors it looks up by name stay missing

Requirements

MelonLoader	0.7.3+ - the mod loader
Anything else	Nothing

Install

Mod manager: install and it places both files for you.

By hand:

1. Polyfill.Boot.dll into Plugins/
2. Polyfill.dll into Mods/ (optional - it only adds the console commands)

The plugin does the work and has to be a plugin, because it runs before any mod is read from disk. A copy of it in Mods/ is ignored by MelonLoader.

Console

Needs the developer console enabled in the game’s settings.

polyfill                 what it found in your mods at startup
polyfilllist             every mod, with its verdict
polyfillshow <mod>       everything one mod asks for that is missing
polyfillunfixed <mod>    only what cannot be pointed at anything
polyfillexport           write one file with everything, ready to send
polyfillprobe <type>     ask the runtime whether a name resolves
polyfillrestore          undo every repair, takes effect on the next launch
polyfillregen            have MelonLoader build the game's generated assemblies again

After a game update Polyfill notices that MelonLoader rebuilt those assemblies and starts from the new ones. polyfillregen is for the case where it says it cannot find an untouched copy of something: it asks MelonLoader to build the whole set again, which takes a few minutes on the next launch.

The full report is written to UserData/Polyfill/last-run.txt, and the untouched copy of anything it changed sits next to it as <name>.dll.polyfill-orig.

Settings

MelonPreferences.cfg, category Polyfill:

• Enabled - off means nothing is read and nothing is changed
• DryRun - work out what is missing, write the report, leave the game alone

What it cannot fix

• Behaviour behind an unchanged signature. A method that kept its name and now does something else.
• Reordered enum values used as plain numbers. The compiler erased the type; a 12 is not distinguishable from an array index. It is reported, never rewritten - guessing wrong here writes into your save.
• A type that moved AND was renamed. .NET type forwarding matches on the name, so it cannot follow ScheduleOne.Weather.X to ScheduleOne.Core.Weather.X.
• Removed with no successor. A forwarder needs something to point at.
• Scene and prefab paths. transform.Find("UI/HUD/...") compiles forever and returns null. No rule can find these: they are strings, so nothing reports them and the mod simply does nothing. A named repair for one mod is possible where the old effect is unambiguous - GraphicsMOD’s lighting toggle is one - but that is a hand-written fix per mod, never a rule that keeps paths working.

Everything in that list shows up as a line in the report rather than as a crash.

Planned

• A compatibility index. Right now finding out that a mod is still broken depends on somebody running polyfillexport and sending the file. A small opt-in service would collect the same thing automatically and publish which mods run on which game version, so the gaps are visible without anyone doing anything. Design and the open questions: Workspace/docs/Polyfill/COMPAT-INDEX.md.

Building

dotnet build Boot/Polyfill.Boot.csproj -c Release
dotnet build Report/Polyfill.csproj -c Release

Both need the Schedule I workspace libraries; point WorkspaceLibPath at them.

Credits

Schedule I by TVGS. Built on MelonLoader and Mono.Cecil.

License

MIT - see LICENSE.md.