Publishing broken by commit a7fb709 : Cannot get property 'group' on null object

[simon-greatrix]

Shadow Version

8.1.1

Gradle Version

8.2.1

Expected Behavior

Publish should not fail with a NullPointerException

Actual Behavior

> Task :generatePomFileForShadowPublication FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':generatePomFileForShadowPublication'.
> Could not apply withXml() to generated POM
   > Cannot get property 'group' on null object

With --stacktrace option:

Caused by: org.gradle.api.InvalidUserCodeException: Could not apply withXml() to generated POM
        at org.gradle.api.internal.UserCodeAction.execute(UserCodeAction.java:41)
        at org.gradle.internal.ImmutableActionSet$SingletonSet.execute(ImmutableActionSet.java:225)
        at org.gradle.internal.MutableActionSet.execute(MutableActionSet.java:41)
        at org.gradle.internal.xml.XmlTransformer$XmlProviderImpl.apply(XmlTransformer.java:187)
        at org.gradle.internal.xml.XmlTransformer.doTransform(XmlTransformer.java:158)
        at org.gradle.internal.xml.XmlTransformer.doTransform(XmlTransformer.java:146)
        at org.gradle.internal.xml.XmlTransformer.transform(XmlTransformer.java:109)
        at org.gradle.internal.xml.XmlTransformer$1.execute(XmlTransformer.java:86)
        at org.gradle.internal.xml.XmlTransformer$1.execute(XmlTransformer.java:83)
        at org.gradle.internal.IoActions$TextFileWriterIoAction.execute(IoActions.java:146)
        ... 124 more
Caused by: java.lang.NullPointerException: Cannot get property 'group' on null object
        at com.github.jengelman.gradle.plugins.shadow.ShadowExtension$_component_closure3$_closure5$_closure6.doCall(ShadowExtension.groovy:37)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

Analysis

Commit a7fb709 - see a7fb709 introduced this issue.

The old code:

                project.configurations.shadow.allDependencies.each {
                    if ((it instanceof ProjectDependency) || ! (it instanceof SelfResolvingDependency)) {
                        def dependencyNode = dependenciesNode.appendNode('dependency')
                        dependencyNode.appendNode('groupId', it.group)
                        dependencyNode.appendNode('artifactId', it.name)
                        dependencyNode.appendNode('version', it.version)
                        dependencyNode.appendNode('scope', 'runtime')
                    }

In this old (working) code, the dependency node is only added when the IF statement matches.

The new code:

        final def allDependencies = project.provider {
            project.configurations.shadow.allDependencies.collect {
                if ((it instanceof ProjectDependency) || ! (it instanceof SelfResolvingDependency)) {
                    new Dep(it.group, it.name, it.version)
                }
            }
        }
...
...
...
                allDependencies.get().each {
                    def dependencyNode = dependenciesNode.appendNode('dependency')
                    dependencyNode.appendNode('groupId', it.group)
                    dependencyNode.appendNode('artifactId', it.name)
                    dependencyNode.appendNode('version', it.version)
                    dependencyNode.appendNode('scope', 'runtime')
                }

This new code introduces the bug. I had two SelfResolvingDependency instances in my configuration and these did not match the 'IF" condition and hence the closure returned a null.

When the each call loops over allDependencies the null causes an exception.

[simon-greatrix]

I am a Java programmer, not a Groovy programmer, but I believe the required fix is to simply change the collect to findResults in the creation of allDependencies.

[jimshowalter]

Ran into the exact same problem when trying to upgrade from 7.x to 8.x.

[jimshowalter]

Here's a reproducible test case (it probably could be shrunk some more, but the key point is it demonstrates the problem).

Unzip it.

cd into the project.

Execute ./gradlew generatePomFileForMavenJavaPublication

Fails with the error.

Fails with any 8.x version of shadow.

In gradle.properties, change shadowVersion to 7.1.2.

Execute ./gradlew wrapper --gradle-version=7.6.3

Re-execute ./gradlew generatePomFileForMavenJavaPublication

Works.

problem.zip

[jimshowalter]

Is there anything we can do in our Gradle configuration to work around this bug?

[Goooler]

Can you try out 9.0.0-beta4?