android.libraryVariants not found

I’ve a custom gradle task that performs some operations on .aar files. It resides in a custom plugin which is applied in a android library project build.gradle file.

The problem is when I try to build the project, gradle throws the following error. Basically it’s complaining about the android.libraryVariants object in the custom task. To cross check if android.XXX properties are available in my custom plugin, I replaced android.libraryVariants with android.applicationVariants and things start working fine.

I’m not quite sure what exactly might be wrong here considering my rudimentary gradle knowledge.

Code is inside a groovy file.

import org.gradle.api.internal.tasks.options.Option
import org.gradle.api.tasks.Input
import org.gradle.api.DefaultTask
import org.gradle.api.publish.maven.MavenPublication
import org.gradle.api.tasks.TaskAction

class BuildAndUpload extends DefaultTask {
    public BuildAndUpload() {
        if(getProject().getPlugins().hasPlugin("com.android.library")) {
            getProject().getPluginManager().apply("maven-publish")
            getProject().android.libraryVariants.all { variant ->
                variant.outputs.all {
                    outputFileName = "${_groupID}-${_artifactID}-${android.defaultConfig.versionName}.aar"
                }
            }
		}
	}
}

class MyGradlePlguins implements Plugin<Project> {
    @Override
    void apply(Project project) {
        BuildAndUpload buildAndUpload = project.getTasks().create("BuildAndUpload", BuildAndUpload.class);
    }
}

The gradle plugin is being developed in Intellij idea and the gradle version is:

distributionUrl=https://services.gradle.org/distributions/gradle-3.5-rc-2-all.zip

Build.gradle of gradle plugin project:

apply plugin: ‘groovy’
apply plugin: ‘java’
apply plugin: ‘maven’

//def _remoteRepoUrl = “http://192.168.8.104:8080/repo
def _remoteRepoUrl = “C:\Users\Umer\localMavenRepo\repo”

sourceCompatibility = 1.8

repositories {
mavenCentral()
}

uploadArchives {
repositories {
mavenDeployer {
repository(url: uri(_remoteRepoUrl))
}
}
}

dependencies {
compile gradleApi()
compile localGroovy()
compile ‘org.codehaus.groovy:groovy-all:2.4.10’
compile ‘com.google.code.gson:gson:2.8.4’
compile (‘io.reactivex.rxjava2:rxjava:2.1.17’) {
exclude group: ‘com.android.support’, module: ‘multidex’
exclude group: ‘xerces’, module: ‘xercesImpl’
}
testCompile group: ‘junit’, name: ‘junit’, version: ‘4.12’
}

Gradle version and build.gradle of the android library project:

buildscript {

repositories {
    google()
    jcenter()
   
}
dependencies {
    classpath 'com.android.tools.build:gradle:3.2.1'
    classpath 'com.xyz:gradlePlugins:0.1.5-SNAPSHOT'
}

}

allprojects {
repositories {
google()
jcenter()
}
}

task clean(type: Delete) {
delete rootProject.buildDir
}

Error Message:

Could not get unknown property 'android' for object of type com.android.build.gradle.internal.api.LibraryVariantOutputImpl.

Error Stacktrace:

org.gradle.api.ProjectConfigurationException: A problem occurred configuring project ':app'.
	at org.gradle.configuration.project.LifecycleProjectEvaluator.addConfigurationFailure(LifecycleProjectEvaluator.java:94)
	at org.gradle.configuration.project.LifecycleProjectEvaluator.notifyAfterEvaluate(LifecycleProjectEvaluator.java:89)
	at org.gradle.configuration.project.LifecycleProjectEvaluator.doConfigure(LifecycleProjectEvaluator.java:70)
	at org.gradle.configuration.project.LifecycleProjectEvaluator.access$100(LifecycleProjectEvaluator.java:34)
	at org.gradle.configuration.project.LifecycleProjectEvaluator$ConfigureProject.run(LifecycleProjectEvaluator.java:110)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
	at org.gradle.configuration.project.LifecycleProjectEvaluator.evaluate(LifecycleProjectEvaluator.java:50)
	at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:667)
	at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:136)
	at org.gradle.execution.TaskPathProjectEvaluator.configure(TaskPathProjectEvaluator.java:35)
	at org.gradle.execution.TaskPathProjectEvaluator.configureHierarchy(TaskPathProjectEvaluator.java:62)
	at org.gradle.configuration.DefaultBuildConfigurer.configure(DefaultBuildConfigurer.java:38)
	at org.gradle.initialization.DefaultGradleLauncher$ConfigureBuild.run(DefaultGradleLauncher.java:261)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
	at org.gradle.initialization.DefaultGradleLauncher.configureBuild(DefaultGradleLauncher.java:173)
	at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:132)
	at org.gradle.initialization.DefaultGradleLauncher.getConfiguredBuild(DefaultGradleLauncher.java:110)
	at org.gradle.internal.invocation.GradleBuildController$2.call(GradleBuildController.java:87)
	at org.gradle.internal.invocation.GradleBuildController$2.call(GradleBuildController.java:84)
	at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:152)
	at org.gradle.internal.invocation.GradleBuildController.doBuild(GradleBuildController.java:100)
	at org.gradle.internal.invocation.GradleBuildController.configure(GradleBuildController.java:84)
	at org.gradle.tooling.internal.provider.runner.ClientProvidedBuildActionRunner.run(ClientProvidedBuildActionRunner.java:64)
	at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
	at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
	at org.gradle.tooling.internal.provider.ValidatingBuildActionRunner.run(ValidatingBuildActionRunner.java:32)
	at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner$1.run(RunAsBuildOperationBuildActionRunner.java:43)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
	at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner.run(RunAsBuildOperationBuildActionRunner.java:40)
	at org.gradle.tooling.internal.provider.SubscribableBuildActionRunner.run(SubscribableBuildActionRunner.java:51)
	at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:49)
	at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:32)
	at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:39)
	at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:25)
	at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:80)
	at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:53)
	at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:57)
	at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:32)
	at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:36)
	at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:25)
	at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:43)
	at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:29)
	at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:64)
	at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:29)
	at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:59)
	at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:44)
	at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:45)
	at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:30)
	at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:67)
	at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:37)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:26)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:34)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:74)
	at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:72)
	at org.gradle.util.Swapper.swap(Swapper.java:38)
	at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:72)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:55)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:62)
	at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:82)
	at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
	at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
	at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:50)
	at org.gradle.launcher.daemon.server.DaemonStateCoordinator$1.run(DaemonStateCoordinator.java:295)
	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
	at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
	at java.lang.Thread.run(Thread.java:745)
Caused by: groovy.lang.MissingPropertyException: Could not get unknown property 'android' for object of type com.android.build.gradle.internal.api.LibraryVariantOutputImpl.
	at org.gradle.internal.metaobject.AbstractDynamicObject.getMissingProperty(AbstractDynamicObject.java:86)
	at org.gradle.internal.metaobject.ConfigureDelegate.getProperty(ConfigureDelegate.java:130)
	at org.codehaus.groovy.runtime.InvokerHelper.getProperty(InvokerHelper.java:174)
	at groovy.lang.Closure.getProperty(Closure.java:291)
	at org.codehaus.groovy.runtime.callsite.PogoGetPropertySite.getProperty(PogoGetPropertySite.java:50)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:307)
	at com.xyz.gradlePlugins.plugins.BuildAndUpload$_closure1$_closure2.doCall(BuildAndUpload.groovy:38)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
	at groovy.lang.Closure.call(Closure.java:414)
	at groovy.lang.Closure.call(Closure.java:430)
	at org.gradle.api.internal.ClosureBackedAction.execute(ClosureBackedAction.java:71)
	at org.gradle.util.ConfigureUtil.configureTarget(ConfigureUtil.java:160)
	at org.gradle.util.ConfigureUtil.configure(ConfigureUtil.java:106)
	at org.gradle.util.ConfigureUtil$1.execute(ConfigureUtil.java:123)
	at org.gradle.api.internal.DefaultDomainObjectCollection.all(DefaultDomainObjectCollection.java:136)
	at org.gradle.api.internal.DefaultDomainObjectCollection.all(DefaultDomainObjectCollection.java:154)
	at org.gradle.api.DomainObjectCollection$all$2.call(Unknown Source)
	at com.xyz.gradlePlugins.plugins.BuildAndUpload$_closure1.doCall(BuildAndUpload.groovy:37)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
	at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1022)
	at groovy.lang.Closure.call(Closure.java:414)
	at groovy.lang.Closure.call(Closure.java:430)
	at org.gradle.api.internal.ClosureBackedAction.execute(ClosureBackedAction.java:71)
	at org.gradle.util.ConfigureUtil.configureTarget(ConfigureUtil.java:160)
	at org.gradle.util.ConfigureUtil.configure(ConfigureUtil.java:106)
	at org.gradle.util.ConfigureUtil$1.execute(ConfigureUtil.java:123)
	at org.gradle.internal.ImmutableActionSet$SingletonSet.execute(ImmutableActionSet.java:155)
	at org.gradle.internal.MutableActionSet.execute(MutableActionSet.java:35)
	at org.gradle.api.internal.DefaultDomainObjectCollection.doAdd(DefaultDomainObjectCollection.java:204)
	at org.gradle.api.internal.DefaultDomainObjectCollection.add(DefaultDomainObjectCollection.java:198)
	at com.android.build.gradle.LibraryExtension.addVariant(LibraryExtension.java:93)
	at com.android.build.gradle.internal.ApiObjectFactory.create(ApiObjectFactory.java:132)
	at com.android.build.gradle.BasePlugin.lambda$createAndroidTasks$6(BasePlugin.java:789)
	at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:81)
	at com.android.build.gradle.BasePlugin.createAndroidTasks(BasePlugin.java:775)
	at com.android.build.gradle.BasePlugin.lambda$null$4(BasePlugin.java:670)
	at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:81)
	at com.android.build.gradle.BasePlugin.lambda$createTasks$5(BasePlugin.java:666)
	at org.gradle.internal.event.BroadcastDispatch$ActionInvocationHandler.dispatch(BroadcastDispatch.java:91)
	at org.gradle.internal.event.BroadcastDispatch$ActionInvocationHandler.dispatch(BroadcastDispatch.java:80)
	at org.gradle.internal.event.AbstractBroadcastDispatch.dispatch(AbstractBroadcastDispatch.java:42)
	at org.gradle.internal.event.BroadcastDispatch$SingletonDispatch.dispatch(BroadcastDispatch.java:230)
	at org.gradle.internal.event.BroadcastDispatch$SingletonDispatch.dispatch(BroadcastDispatch.java:149)
	at org.gradle.internal.event.AbstractBroadcastDispatch.dispatch(AbstractBroadcastDispatch.java:58)
	at org.gradle.internal.event.BroadcastDispatch$CompositeDispatch.dispatch(BroadcastDispatch.java:324)
	at org.gradle.internal.event.BroadcastDispatch$CompositeDispatch.dispatch(BroadcastDispatch.java:234)
	at org.gradle.internal.event.ListenerBroadcast.dispatch(ListenerBroadcast.java:140)
	at org.gradle.internal.event.ListenerBroadcast.dispatch(ListenerBroadcast.java:37)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
	at com.sun.proxy.$Proxy31.afterEvaluate(Unknown Source)
	at org.gradle.configuration.project.LifecycleProjectEvaluator.notifyAfterEvaluate(LifecycleProjectEvaluator.java:76)
	... 85 more