UNT0031 Asset operations in LoadAttribute method

Asset operations such as asset loading should be avoided in methods decorated with InitializeOnLoadMethod / DidReloadScripts or static constructors in types decorated with InitializeOnLoad. Those methods are called before asset importing is completed and therefore the asset loading can fail resulting in a null object.

Examples of patterns that are flagged by this analyzer

using UnityEditor;

class Loader
{
    [InitializeOnLoadMethod]
    public void Foo() {
        object[] assets = AssetDatabase.LoadAllAssetsAtPath(""foo"");
    }
}

Solution

To do initialization after a domain reload which requires asset operations use the AssetPostprocessor.OnPostProcessAllAssets callback. This callback supports all asset operations and has a parameter signaling if there was a domain reload.