[GROOVY-7896] Grape `@Grab` annotation calls zero-arg methods when installing jar with extension module

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Invalid
• Affects Version/s: 2.4.7
• Component/s: Grape
• Assignee: Unassigned
• Reporter: Ted Naleid
• Created: 31/Jul/16 20:56
• Updated: 02/Aug/16 23:13
• Resolved: 02/Aug/16 02:41

Description

When using @Grab annotation and loading a jar file that extends classes via extension modules, it appears that it is silently calling zero-arg methods on the extension class.

I've created a test project that shows this issue: https://github.com/tednaleid/groovybug-ext

Here's the detail. If I have a class that extends String and also has a zero-arg initialize() method that's meant to be called by the user:

com/naleid/groovybug/StringExtensions.java

package com.naleid.groovybug;

public abstract class StringExtensions {

    private static String append = null;

    private StringExtensions() { }

    public static void initialize() {
        System.out.println("initialized");
        if (append != null) {
            throw new RuntimeException("Already initialized");
        }
        append = "foo";
    }

    public static String appendFoo(String self) {
        return self + append;
    }
}

and this in resources so it's registered:

META-INF/services/org.codehaus.groovy.runtime.ExtensionModule

moduleName=string-ext
moduleVersion=
extensionClasses=com.naleid.groovybug.StringExtensions

If I create a jar out of it, install it in my .m2 directory (linked gradle script does this with ./gradlew install and then run this script:

demoBug.groovy

@Grab('groovybug:groovybug-ext:1.0')

import com.naleid.groovybug.StringExtensions

assert "bar ".appendFoo() == "bar null"

StringExtensions.initialize()

assert "bar ".appendFoo() == "bar foo"

println "success!"

it fails with

Caught: Assertion failed:

assert "bar ".appendFoo() == "bar null"
              |           |
              bar foo     false

Assertion failed:

assert "bar ".appendFoo() == "bar null"
              |           |
              bar foo     false

	at demoBug.run(demoBug.groovy:12)

If I remove the @Grab annotation and instead refer to the jar file via the classpath, it works fine:

groovy -classpath ~/.m2/repository/groovybug/groovybug-ext/1.0/groovybug-ext-1.0.jar demoWorking.groovy
initialized
success!

The linked project demos the issue. Where I hit it in "real life" was using @Grab on a Ratpack application that has a RxRatpack.initialize() method. This method was already called and it was confusing to have this ratpack script fail:

ratpackTest.groovy

@Grab('io.ratpack:ratpack-rx:1.3.3')

import ratpack.rx.RxRatpack
RxRatpack.initialize()

The initialize() blows up if it has already been called.

java.lang.IllegalStateException: Cannot install RxJava integration because another execution hook (class rx.plugins.RxJavaObservableExecutionHookDefault) is already installed
	at ratpack.rx.RxRatpack.initialize(RxRatpack.java:102)
	at ratpack.rx.RxRatpack$initialize.call(Unknown Source)
	at ConsoleScript0.run(ConsoleScript0:5)