Detect when a build is started

Unity Engine
1

Is there a way to detect when a build is started?
I have some code that subscribes to
EditorSceneManager.newSceneCreated
With a

[InitializeOnLoad]

It seems like the Building Process creates a few empty scenes, which then executes my delegate.
I tried using

#if UNITY_EDITOR

But off course that doesn’t work because building still happens inside the editor.
Also looked into

UnityEditor.Compilation

but couldn’t find a solution.

2

would any of these be accessible,
https://github.com/Unity-Technologies/UnityCsReference/search?q=build+started&unscoped_q=build+started

3

The AssemblyBuilder looked promesing but as i understode the use of it is to add scripts to the assembly that are outside the asset folder. So you have to create an AssemblyBuilder, give it a path and an array of scripts.
Will look further into EditorCompilation class, but my main question for that one is how to get a reference to it?

4

Just found this one. Sounds like it would do the trick. Not behind my pc atm, will test later and post an answer if it works or not.

5

doesnt seem to do anything if hit build, does trigger on script recompile when edit something, like this one
https://github.com/m3rt32/UnityElevatorCompiler

6

Thanks for checking.

7

ok found it:

UnityEditor.BuildPipeline.isBuildingPlayer