How to use @Library in an imported groovy script in Jenkins declarative pipeline?

Question

What I have is a following:

1. global shared library created as described here. Nothing special, one script in vars folder called deleteFile.gr

Answer 1

For this use case, it will make more sense to use the library step to dynamically load it at runtime.

In your firstPipe.groovy you could do something like:

final myOneLib = library('myOneLib')

def execute(String zCmakeListsPath){
  stage('some kind of stage 2') {
    echo "Hello from stage 1 with " + zCmakeListsPath
    echo "var attempt ${env.mySrcDir}"

  }
  stage('second stage'){
    echo "and one from stage 2"
    echo "param was " + zCmakeListsPath
    echo "var attempt ${env.myBuildDir}"
    //call function from global lib
    myOneLib.deleteFile 'for 3rd party global library now'
  }
}

return this

See the Loading libraries dynamically section of the Extending with Shared Libraries documentation.