Existing docs about writing Shared Libraries are mostly cover an old 'Scripted Pipeline'.

I have a shared library which perfectly works when pipeline is defined in a 'scripted' manner. However, it doesn't work when I use new 'Declarative' pipeline syntax.

Here's the "variable" code which leads to StackOverflowException on Jenkins. Can't figure out why.

// vars/buildStage.groovy
import io.oscript.buildSteps

def call(body){

  def steps = new buildSteps()

  body.resolveStrategy = Closure.DELEGATE_FIRST
  body.delegate = steps
  body()
}

In the scripted pipeline this variable encloses methods of my build. All steps are implemented in buildSteps class, and every method is symply a 'bat $script'

Here's Declarative pipeline fragment

steps {

    buildStage {

    {

       clean() // main method

      }

}

Call to this library causes StackOverflowException on Jenkins.

java.lang.StackOverflowError
at groovy.lang.MetaClassImpl.getMethodWithCachingInternal(MetaClassImpl.java:1318)
at groovy.lang.MetaClassImpl.createPojoCallSite(MetaClassImpl.java:3368)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.createPojoSite(CallSiteArray.java:132)

If you switch back to old syntax, it works.

So, here's the request: Please improve Shared Libraries documentation and tell us how to write Shared Libraries for Declarative Syntax.

My sources are attached.