Groovy 4 Breaking Change for Grab Annotations

There has been a breaking change in Groovy 4 for users using @Grab to import certain libraries. This page describes the error that occurs, the symptoms, and the solutions you can implement. 

Summary of the problem

We have noticed that some users encounter the error below after upgrading to Scriptrunner version 8.0.0 or newer. This error is caused by using the @Grab annotation to import libraries into a script where that library has transitive dependencies that are not compatible with Groovy 4. All ScriptRunner versions from 8.0.0 onwards use Groovy 4. If a library imported with @Grab has transitive dependencies incompatible with Groovy 4, it will cause script compilation to break.

This is not a ScriptRunner-specific bug. It impacts anyone using Groovy 4 on any platform.

Error

 
No such property: importPackages for class: org.codehaus.groovy.ast.ModuleNode

Symptoms

If you have triggered a script that contains a @Grab call that pulls in a problematic library, it will cause all features in ScriptRunner that use user-created scripts to stop working and produce the above error. This is because once the script has been triggered the incompatible library is added to the classpath, which all ScriptRunner features use.

Solution

There are three main solution paths you can take and these are described below. 

Solution 1: Update the @Grab call not to import transitive dependencies

An example @Grab call that can cause this error on Groovy 4 is shown below:

 
@Grab('com.github.groovy-wslite:groovy-wslite:1.1.2')

To prevent the @Grab call from pulling in transitive dependencies, you would amend the above to:

 
@Grab('com.github.groovy-wslite:groovy-wslite:1.1.2;transitive=false')

This will not take effect until you run the Clear the Groovy class loader cache built-in script, which removes the broken dependencies from the class loader.

Solution 2: Update the version of the library you are  importing with @Grab to a version that is compatible with Groovy 4

The quickest way to determine if the @Grab imported library works in Groovy 4 is to try it on Groovy 4. If you have Groovy installed locally on your machine, you can use the groovyconsole as described in the Apache Groovy documentation.

If you have a test server running ScriptRunner 8.0.0 or newer, you can try it in the Script console, but remember, if you trigger the error, you must clear the class loader cache again to fix it. Do not do this in production because it will stop all ScriptRunner features from working.

Solution 3: Use a library that is already part of ScriptRunner to do what your @Grab library is doing

This solution involves removing @Grab calls and using existing libraries provided with ScriptRunner.

@Grab makes external calls to download libraries. If a library is already available on the classpath, you can avoid these external calls and use a standard import statement instead.

Several users import libraries with @Grab that allow them to make REST calls. ScriptRunner includes the org.codehaus.groovy.modules.http-builder library, which is documented here. This library can most likely do whatever you need to do concerning making external REST calls. This library has classes like  groovyx.net.http.HTTPBuilder and groovyx.net.http.RESTClient. Both classes can be accessed with a simple import, with no @Grab calls required.

For example, if you want to make a GET REST call with a REST client, you can do this:

groovy
import groovyx.net.http.RESTClient

def client = new RESTClient('https://jsonplaceholder.typicode.com')
def resp = client.get( path: '/todos/1' )

resp['data']