[LOG4J2-1803] JMH generated benchmark classes not included in jar

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.8
• Fix Version/s: 2.8.1
• Component/s: Core, Performance Benchmarks
• Assignee: Ralph Goers
• Reporter: Remko Popma
• Created: 30/Jan/17 18:37
• Updated: 02/Feb/17 15:44
• Resolved: 02/Feb/17 15:43

Description

Some time after the 2.7 release, the JMH benchmarks stopped working. When trying to execute them, this error occurs:

java.lang.IllegalArgumentException: Benchmark does not match a class
	at org.openjdk.jmh.util.ClassUtils.loadClass(ClassUtils.java:90)
	at org.openjdk.jmh.runner.BaseRunner.runBenchmark(BaseRunner.java:198)
	at org.openjdk.jmh.runner.BaseRunner.runBenchmarks(BaseRunner.java:95)
	at org.openjdk.jmh.runner.ForkedRunner.run(ForkedRunner.java:51)
	at org.openjdk.jmh.runner.ForkedMain.main(ForkedMain.java:68)
Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.perf.jmh.generated.FileAppenderBenchmark_julFile
	at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:195)
	at org.openjdk.jmh.util.ClassUtils.loadClass(ClassUtils.java:72)
	... 4 more

When I build the project, the classes generated by JMH under log4j-perf/target/generated-sources/annotations are not included in the shaded benchmarks.jar or in log4j-perf-2.8.1-SNAPSHOT.jar...

The cause seems to be a change in the master pom:
the maven-compiler-plugin plugin now has the below section which was not there in 2.7.

If I take it out and build only log4j-perf, the benchmarks run without error. (But building all modules fails: some problem in log4j-core...)

  <executions>
    <execution>
      <!-- disable annotation processing for first pass -->
      <id>default-compile</id>
      <goals>
        <goal>compile</goal>
      </goals>
      <phase>compile</phase>
      <configuration>
        <proc>none</proc>
      </configuration>
    </execution>
    <execution>
      <!-- then do a processing-only pass to generate plugins .dat file -->
      <id>process-plugins</id>
      <goals>
        <goal>compile</goal>
      </goals>
      <phase>process-classes</phase>
      <configuration>
        <proc>only</proc>
      </configuration>
    </execution>
  </executions>

From the log4j-dev mailing list:

That maven-compiler-plugin config was originally only included in log4j-core in order to allow the PluginProcessor annotation processor to re-run against log4j-core without needing to split it into its own jar. I'm not sure why it's configured for everything now.

Potentially related: somebody reported on StackOverflow that their custom plugin no longer loads with 2.8.