`gradlew` compiling successfully without checking for symbols on the classpath - gradle

Question

I am using a gradle project to build a Jenkins shared library. I have a build.gradle with following content:
// Apply the groovy plugin to add support for groovy
apply plugin: 'groovy'
sourceSets {
main {
groovy {
srcDirs = ['src', 'vars']
}
}
test {
groovy {
srcDirs = ['test']
}
}
}
// In this section you declare where to find the dependencies of your project
repositories {
// Use 'jcenter' for resolving your dependencies.
jcenter()
// You can declare any Maven/Ivy/file repository here.
maven {
url "https://repo.jenkins-ci.org/releases/"
}
}
// In this section you declare the dependencies for your production and test code
dependencies {
compile 'org.codehaus.groovy:groovy-all:2.5.6'
compile 'org.apache.ivy:ivy:2.4.0'
testCompile 'junit:junit:4.12'
}
Inside my vars/ directory I have the following source code in it:
def call(Map params) {
2 pipeline {
3 agent none
4
5 stages {
6 stage('Build') {
7 agent { label 'maven'}
8 steps {
9 logError 'Hello world'
10 }
11 }
12 }
13 }
14 }
When I run ./gradlew build or ./gradlew compileGroovy the compilation goes through fine. It looks it is only doing syntax validation and does not care about linking the symbols such as pipeline or agent etc. Am I understanding it correctly?

Answer 1

Okay I think I figured it out. This is happening because groovyc (in this case gradlew compileGroovy is producing a byte code that does not translate high level language to its bytecode equivalent. Instead each line is replaced by a method dispatch. So line 2 in the code above will get replaced with
getMetaClass().invokeMethod(this, 'pipeline', closure)
This causes compile time check on pipeline symbol to be promoted to a runtime error.