Is it possible to enable -Werror for JavaCompile in gradle?

Question

I have an Android project set up in Gradle using the com.android.application plugin. I want javac lint warnings to trigger errors instead of just warnings.

The following works just fine for warnings:

tasks.withType(JavaCompile).all {
    options.compilerArgs.add("-Xlint:all")
}

However, adding -Werror to it:

tasks.withType(JavaCompile).all {
    options.compilerArgs.add("-Xlint:all")
    options.compilerArgs.add("-Werror")
}

causes the build to completely fail (not in the right way):

FAILURE: Build failed with an exception.

What went wrong: Execution failed for task ':app:compileDebugJava'.
java.lang.NullPointerException

Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Calling gradle with --stacktrace shows:

Exception is: org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:compileDebugJava'.
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
    at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:64)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:42)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
    at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
    at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:305)
    at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.executeTask(AbstractTaskPlanExecutor.java:79)
    at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:63)
    at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:51)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:23)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:88)
    at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:29)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:62)
    at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23)
    at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:68)
    at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:62)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:55)
    at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:149)
    at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:106)
    at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:86)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:80)
    at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:33)
    at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:24)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:36)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:26)
    at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:51)
    at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:171)
    at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:237)
    at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:210)
    at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:35)
    at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24)
    at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:206)
    at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:169)
    at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
    at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
    at org.gradle.launcher.Main.doAction(Main.java:33)
    at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
    at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:54)
    at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:35)
    at org.gradle.launcher.GradleMain.main(GradleMain.java:23) 
    Caused by: java.lang.RuntimeException: java.lang.NullPointerException
    at com.sun.tools.javac.main.Main.compile(Main.java:469)
    at com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:132)
    at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:42)
    at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:35)
    at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.delegateAndHandleErrors(NormalizingJavaCompiler.java:97)
    at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:50)
    at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:36)
    at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:34)
    at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:25)
    at org.gradle.api.tasks.compile.JavaCompile.performCompilation(JavaCompile.java:158)
    at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:138)
    at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:92)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:63)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$IncrementalTaskAction.doExecute(AnnotationProcessingTaskFactory.java:235)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:211)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$IncrementalTaskAction.execute(AnnotationProcessingTaskFactory.java:222)
    at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:200)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
    ... 44 more
    Caused by: java.lang.NullPointerException
    at dagger.internal.codegen.Util.getAnnotation(Util.java:192)
    at dagger.internal.codegen.GraphAnalysisProcessor.process(GraphAnalysisProcessor.java:105)
    at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:793)
    at com.sun.tools.javac.processing.JavacProcessingEnvironment.access$200(JavacProcessingEnvironment.java:97)
    at com.sun.tools.javac.processing.JavacProcessingEnvironment$DiscoveredProcessors$ProcessorStateIterator.runContributingProcs(JavacProcessingEnvironment.java:644)
    at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1027)
    at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1185)
    at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1108)
    at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:824)
    at com.sun.tools.javac.main.Main.compile(Main.java:439)     ... 62 more

Is adding -Werror not supported?

Answer 1

For googlers:

If you want fail on kotlin warnings, add to the root build.gradle.kts:

allprojects {
    project.tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
        kotlinOptions {
            jvmTarget = JavaVersion.VERSION_11.toString()
            allWarningsAsErrors = true
        }
    }
}

Answer 2

javac lint

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.0.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
    gradle.projectsEvaluated {
        tasks.withType(JavaCompile) {
            options.compilerArgs << "-Xlint:all" << "-Werror"
        }
    }
}

result would be next

....
:app:compileDebugJava                 
D:\Android\stack-overflow\ui\app\src\main\java\com\tivogi\ui\activity\MainActivity.java:22: warning: [deprecation] getLastNonConfigurationInstance() in Activity has been deprecated
        getLastNonConfigurationInstance();
        ^                             
error: warnings found and -Werror specified
1 error                               
1 warning                             
:app:compileDebugJava FAILED          

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:compileDebugJava'.
> Compilation failed; see the compiler error output for details.

* Try:        
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED  

Total time: 2.421 secs

Android Lint

From Android Lint support at Gradle Plugin User Guide

android {
    lintOptions {
        ...
        // if true, treat all warnings as errors
        warningsAsErrors true
        ...
    }
}