Lombok annotation processor not added to modules of a Maven multi-module project

[iorjfeiofjseoirf]

What version of OpenRewrite are you using?

• OpenRewrite v8.83.0
• Maven plugin v6.40.0
• rewrite-migrate-java v3.35.0

How are you running OpenRewrite?

via Maven on a multi-module project

What is the smallest, simplest way to reproduce the problem?

This is a multi-module project with a root and two modules. One of the modules uses lombok.
I set the version of rewrite-migrate-java to 3.31.2 because the behaviour changed from 3.31.1 to 3.31.2 and is the same from 3.31.2 to 3.35.0.

pom.xml of root module:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>my-app</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>
  <modules>
    <module>with-lombok</module>
    <module>without-lombok</module>
  </modules>

  <properties>
    <maven.compiler.release>21</maven.compiler.release>
  </properties>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.44</version>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <build>
    <plugins>
      <plugin>
        <groupId>org.openrewrite.maven</groupId>
        <artifactId>rewrite-maven-plugin</artifactId>
        <version>6.40.0</version>
        <configuration>
          <exportDatatables>true</exportDatatables>
          <activeRecipes>
            <recipe>org.openrewrite.java.migrate.EnableLombokAnnotationProcessor</recipe>
          </activeRecipes>
        </configuration>
        <dependencies>
          <dependency>
            <groupId>org.openrewrite.recipe</groupId>
            <artifactId>rewrite-migrate-java</artifactId>
            <version>3.31.2</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

pom.xml of module with-lombok:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.example</groupId>
    <artifactId>my-app</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <artifactId>with-lombok</artifactId>

  <dependencies>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
    </dependency>
  </dependencies>
</project>

pom.xml of module without-lombok:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.example</groupId>
    <artifactId>my-app</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <artifactId>without-lombok</artifactId>

</project>

What did you expect to see?

Up to rewrite-migrate-java version 3.31.1, the Lombok annotation processor was added to the parent pom. My understanding is that the intention of #1031 (added in version 3.31.2) was to add the annotation processor only to those modules where lombok is used.

Therefore, I expect

• the pom.xml of the root module to be unchanged,
• the pom.xml of module without-lombok to be unchanged and
• the annotation processor being added to the pom.xml of module with-lombok:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <parent>
   <groupId>org.example</groupId>
   <artifactId>my-app</artifactId>
   <version>1.0-SNAPSHOT</version>
 </parent>

 <artifactId>with-lombok</artifactId>

 <dependencies>
   <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
   </dependency>
 </dependencies>
 <build>
   <plugins>
     <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-compiler-plugin</artifactId>
       <configuration>
         <annotationProcessorPaths>
           <path>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <version>1.18.44</version>
           </path>
         </annotationProcessorPaths>
       </configuration>
     </plugin>
   </plugins>
 </build>
</project>

What did you see instead?

The Lombok annotation processor is added to none of the pom.xml files.

Additional considerations

• The Lombok annotation processor will be added, when I run rewrite:run directly on the module with-lombok. But I doubt that it is the intended behaviour to run the target on each module individually.
• The tests added with Only add lombok annotation processor to modules that use lombok #1031 do not truly use a multi-module project. The new test doesNotAddLombokToModuleWithoutLombok just uses a set of two (unrelated) modules.
• Is traversing the module hierarchy the missing part?

[timtebeek]

Thanks for the report @iorjfeiofjseoirf ; seems like an unfortunate effect of the combination of the preconditon + the recipe tendency to aim for the parent. Any insights here @Jenson3210 ?

[Jenson3210]

Hmmm... sounds like we should make ModuleHasDependency smart enough to also mark the parent if any of its children has a particular dependency. WDYT?

[timtebeek]

Yeah I'm not sure about that; it might have other effects when used as precondition, and even if we make that change we'd add the annotationProcessor to the parent, and with that potentially all projects (and thus conflict with #1031 ). Maybe a dedicated precondition here makes sense? Open to other options.

[Jenson3210]

Root-caused this to upstream AddAnnotationProcessor in rewrite-maven. The visitor's first gate (lines 268–271 of AddAnnotationProcessor.java) only accepts poms that are in parentPomPaths or orphanPomPaths. A child with an in-reactor parent is in neither — so when the outer ModuleHasDependency(lombok) precondition gates the visitor to the lombok-using child only, the visitor early-returns and nothing is written. The "write to parent's <pluginManagement>" path can't help here either, because the parent is filtered out by the precondition and never reaches the visitor.

Broadening the precondition so the parent also passes does produce a write, but into the parent's <pluginManagement> — which by Maven inheritance propagates the annotation processor configuration to every child, including without-lombok. That's not the scoping behavior #1031 was aiming for.

Tracking upstream as openrewrite/rewrite#7850. Once that lands and rewrite-migrate-java picks up the new rewrite-maven, the current EnableLombokAnnotationProcessor recipe should work without further changes here.

• AddAnnotationProcessor: child with in-reactor parent is silently skipped when only the child passes the precondition rewrite#7850