CelesteAnalyzer 1.0.0

CelesteAnalyzer

A Roslyn analyzer which helps you avoid common mistakes made when developing Celeste mods.

Features

CL0001: Lambda passed to ILCursor.EmitDelegate

Passing lambdas to ILCursor.EmitDelegate, like this:

cursor.EmitDelegate((int f) => f * 2);

Emits inefficient IL code similar to this:

ldc.i4 1                                                                                                                             
ldc.i4 38750844                                                                                                                      
call T MonoMod.Utils.DynamicReferenceManager::GetValueTUnsafe<System.Delegate>(System.Int32,System.Int32)                                           
call TResult MonoMod.Cil.FastDelegateInvokers::InvokeTypeVal1<System.Int32,System.Int32>(T0,MonoMod.Cil.FastDelegateInvokers/TypeVal1`2<TResult,T0>)

This analyzer will warn you about this, and recommend to switch to a static method reference (though there's currently no code fixer for this):

cursor.EmitDelegate(Manipulator);

// somewhere in your class
private static int Manipulator(int f) => f * 2;

This translates to a simple call instruction

CL0002: Instance method passed to EmitDelegate

Avoid passing instance methods to ILCursor.EmitDelegate, as it can result in capturing an instance of your class in unexpected ways. The analyzer will warn about this.

CL0003: Orig not called in hook

Warns about not calling the orig method received as the 1st parameter to a On. hook in any code path, as this breaks mod compatibility.

CL0004: Hooks should be static

Warns about non-static methods used as targets for On hooks or manipulators for IL hooks. Provides a code fixer to make them static.