Javac没有运行注释处理器

Question

Problem

I'm revisiting a maven project that I haven't touched in at least a year. I'm pretty sure it was compiling successfully when I left it (there was still a working jar in the target directory), but now compilation fails because generated classes are missing.

What I tried

• Verified there are indeed no sources in target/generated-sources/annotations ( none present )
• Ensured javac wasn't invoked with -proc:none ( it wasn't )
• Ran mvn clean dependency:unpack-dependencies -Dmdep.useSubDirectoryPerArtifact=true to ensure the expected dependencies are on the classpath and that they contain a valid META-INF/services/javax.annotation.processing.Processor entry ( yes there were multiple, including org.immutables.processor.ProxyProcessor )
• Followed these steps from How to make sure javac is using an annotation processor and troubleshoot when it is not :
  1. Take the javac options from the maven debug log
  2. Remove -nowarn option and add -verbose -XprintRounds -XprintProcessorInfo -Xlint -J-verbose . NOTE: I also had to add the relative path to the main class, or javac would complain there are no sources.
  3. Verify if class of processor is loaded ( not present )
  4. Look for at least one processing round log ( none present )
  5. Make sure annotations are present in the list of the round log ( no round log )
• Added -proc:only option to javac command
• Also added -processor org.immutables.processor.ProxyProcessor to javac command ( processor now loaded , but still no rounds printed and no classes generated)
• Changed the processor option to -processor org.immutables.processor.ProxyProcessorXXX to see if it would make a difference ( it did , it now printed a warning stating that processing was requested with proc:only , but no processors were found)
• Checked to see if that warning appeared if I didn't use the -processor option, which should make javac detect processors from class path ( it didn't show the warning, which suggests it's detecting processors yet the log doesn't show any sign of it)
• Tried above after switching from JDK1.8 to JDK9 (using jenv)
• Installed Zulu 1.7 and tried above after switching to it (using jenv)

Possible factors

• I did an entirely clean install of macOS
• I ran macOS Sierra before, currently High Sierra
• Before I didn't have JDK9 installed
• I switched to using Gradle a long time ago, so I might have forgotten an important detail about maven

Command options

This is the javac command I'm currently using:

javac -d./target/classes -classpath./target/classes:$HOME/.m2/repository/com/google/dagger/dagger/2.4/dagger-2.4.jar:$HOME/.m2/repository/com/google/dagger/dagger-compiler/2.4/dagger-compiler-2.4.jar:$HOME/.m2/repository/com/google/auto/factory/auto-factory/1.0-beta3/auto-factory-1.0-beta3.jar:$HOME/.m2/repository/org/immutables/builder/2.3.9/builder-2.3.9.jar:$HOME/.m2/repository/org/immutables/value/2.3.9/value-2.3.9.jar:<LONG LIST OF DIRECT AND TRANSITIVE DEPENDENCIES HERE> -sourcepath./src/main/java: -s./target/generated-sources/annotations -verbose -XprintRounds -XprintProcessorInfo -Xlint -J-verbose -processor org.immutables.processor.ProxyProcessor -proc:only./src/main/java/com/mycompany/myproject/Main.java

NOTE : for better readability, I put each argument on a new line, replaced absolute paths with $HOME/ and ./ and I omitted most dependencies.

Question

What am I missing here? Any suggestions or pointers would be greatly appreciated.

Answer 1

As far as I can remember maven generates a marker file or marker directory (starting with a dot) for generated sources. But it's also a long time ago...

Answer 2

We had the same issue on a git branch, while the main branch built fine. The root cause turned out to be a.java source with a duplicate definition of a private void function. This duplicate was caused by a merge from the main branch. At first we did not notice it, because the merge did not cause conflicts. The problem occurred with Amazon Corretto 8 and 11 compilers. After removing the duplicate private void function, the java compiler started generating sources as before.

Answer 3

javac appears to completely and silently skip annotation processing for some parse failures.

For me a duplicated annotation caused by a merge mistake caused thousands of failures because my annotation processors didn't run - so the real error got completely lost.

@Data @AllArgsConstructor @NoArgsConstructor @EqualsAndHashCode(callSuper = false)
@EqualsAndHashCode(callSuper = false)