For some reason I can't comment so I'm going to have to answer instead. One option (I'm not sure it will work) is to modify the file in the package cache. I believe that unless you clear it, unity will pull the files from there each refresh. Another option is to create a script that runs on project reload and overwrites the file with the version you want.

For some reason I can't comment so I'm going to have to answer instead. One option (I'm not sure it will work) is to modify the file in the package cache. I believe that unless you clear it, unity will pull the files from there each refresh. Another option is to create a script that runs on project reload and overwrites the file with the version you want.

Possible ways to receive callbacks

I haven't tested these and I'm not sure if they will work, but I hope they'll be helpful to you.

• EditorApplication.playModeStateChanged
• IPreprocessBuildWithReport
• AssetsModifiedProcessor
• UnityEditor.Build namespace

You mentioned the project reloading, so EditorApplication.projectChanged might be of help to you as well. These links https://answers.unity.com/questions/704066/callback-before-unity-reloads-editor-assemblies.html https://docs.unity3d.com/ScriptReference/Callbacks.DidReloadScripts.html might also provide you with enough information to solve your problem.

As a last resort, you could create your own copy of ShadowCaster2D and use that behaviour instead of the default one