[Unity3D] #DEVELOPMENT_BUILD not working in PreBuild Script IPreprocessBuildWithReport

I was trying to get some logic to work in a PreBuild script whether the build is a development build or not using the define symbol #DEVELOPMENT_BUILD. It works in regular scripts, but apparently it doesn’t work for PreBuild scripts because the symbol won’t be defined until the build actually starts. So the #DEVELOPMENT_BUILD never actually hits even though you have “Development Build” checked in the Build Settings.

To check whether or not your build is a development build use:

var isDev = (report.summary.options & BuildOptions.Development) != 0;

In the PreBuild script it would look like this:

public void OnPreprocessBuild(BuildReport report)
{
   var isDev = (report.summary.options & BuildOptions.Development) != 0;

   if (isDev) {
    // Is development build
   } else {
    // Normal build
   }
}

Source: https://qiita.com/Clpsplug/items/c34e8f596e54444623ba