JEP247: javac -release command line argument

[mattnelson]

Since errorprone is using a java 9 version of javac the changes introduced in JEP247[1] imply that the release argument should be used to ensure that correct bootclasspath is configured. Should the compiler[2] arguments be updated to use release instead of source/target as well as the build system recommendations for configuration[3,4]?

[1] http://openjdk.java.net/jeps/247
[2] https://github.com/google/error-prone/blob/v2.0.21/check_api/src/main/java/com/google/errorprone/BaseErrorProneJavaCompiler.java#L152
[3] http://errorprone.info/docs/installation#maven
[4] https://maven.apache.org/plugins/maven-compiler-plugin/compile-mojo.html#release

[tbroyer]

See #784, was released in 2.2.0.

Now --release support still requires using Java 9+, and Error Prone works with Java 8, so it cannot use --release internally. Regarding the documentation, that would mean having different snippets depending on the version of Java being used/targeted.

[mattnelson]

Was able to get further using @tbroyer suggestion of switching to javac plugin and bypassing error prone repackaged javac. Verified that the system supplied javac is used by supplying the release flag with 9 and trying to use items introduced in 10. I would like to skip configuration of source/target as they should no longer be needed, but when I remove them error prone can't be loaded. The error doesn't provide much in trying to determine where in errorprone it is failing. Can I get some guidance on where to look?

error

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project maven-base-pom-test: Compilation failure
[ERROR] error: plug-in not found: ErrorProne
[ERROR]
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project maven-base-pom-test: Compilation failure
error: plug-in not found: ErrorProne
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:213)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:290)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:194)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:564)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)
Caused by: org.apache.maven.plugin.compiler.CompilationFailureException: Compilation failure
error: plug-in not found: ErrorProne
at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute (AbstractCompilerMojo.java:1161)
at org.apache.maven.plugin.compiler.CompilerMojo.execute (CompilerMojo.java:168)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:208)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:154)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:146)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:956)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:290)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:194)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:564)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:356)

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                     <!-- errorprone won't load unless source/target are supplied -->
                    <source>10</source>
                    <target>10</target>
                    <!-- javac uses release arg -->
                    <release>10</release>
                    <showDeprecation>true</showDeprecation>
                    <showWarnings>true</showWarnings>
                    <fork>true</fork>
                    <compilerArgs>
                        <arg>-Xplugin:ErrorProne</arg>
                    </compilerArgs>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>com.google.errorprone</groupId>
                            <artifactId>error_prone_core</artifactId>
                            <version>2.3.1</version>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>com.google.errorprone</groupId>
                        <artifactId>error_prone_core</artifactId>
                        <version>2.3.1</version>
                    </dependency>
                </dependencies>
            </plugin>

[cushon]

Please re-open if you're still seeing this with recent versions of Error Prone and the -Xplugin integration documented at http://errorprone.info/docs/installation.