Skip jacoco instrumentation for mvn modules with package type ear

[mfriedenhagen]

In a multi module maven project ear modules are never compiled (similar to pom packaged modules) and the /target/classes directory is never created.

Jacoco correctly skipps modules with pom packaging but it tries to instrument ear modules, which leads to the following error

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.jacoco:jacoco-maven-plugin:0.6.3.201306030806:report (post-test) on project mct-vermittler-vertriebsmanagement-ear: Execution post-test of goal org.jacoco:jacoco-maven-plugin:0.6.3.201306030806:report failed: basedir /var/data/jenkins/workspace/mvp.mct.vermittler-vertriebsmanagement.git.nightly/mct-vermittler-vertriebsmanagement-ear/target/classes does not exist
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:225)
at ...

Caused by: java.lang.IllegalStateException: basedir /var/data/jenkins/workspace/my-project-dir/my-module-ear/target/classes does not exist
at org.codehaus.plexus.util.DirectoryScanner.scan(DirectoryScanner.java:550)
at org.codehaus.plexus.util.FileUtils.getFileAndDirectoryNames(FileUtils.java:1717)
at org.codehaus.plexus.util.FileUtils.getFileNames(FileUtils.java:1645)

[mfriedenhagen]

Hello there, I now included a sample project, however could not reproduce the error. @jlupi: do you execute any tests in your EAR? The default lifecycle for EARs (http://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html#Lifecycle_Reference) does not execute surefire:test at all :-)

[jlupi]

@mfriedenhagen no, of course I do not run any tests inside the ear module, and there are no java classes inside :) . It is just a sub-module of a maven multi module project. From what I observed jacoco instruments every submodule until you explicitly set the skip property.

The maven lifecycle is my point. Mvn does not execute the compile goal for ear packaged modules because there is nothing to compile. That's why it should be skipped by default ;-)

[mfriedenhagen]

@jlupi: this is not always of course :-).

• You might have had defined a deployment of your ear in phase pre-integration-test and run the failsafe:integration-test from within the ear module.
• Here I use XPATH syntax to reference POM structures, e.g. //project/build/plugins would be <project><build><plugins>
• I suspect In the parent pom of your Probably you did not use //project/build/pluginManagement/plugins but the //project/build/plugins section to configure surefire and so forced testing even on a packaging which would not do this normally. Same is true for POMs btw 😁.
• As an immediate remedy/workaround for your current problem, setting the //project/properties/jacoco.skip to true in your EAR module should be enough.

Other solutions:

1. Version and configure jacoco-maven-plugin, maven-surefire-plugin and maven-failsafe-plugin in //project/build/pluginManagement/plugins of your parent pom (also useful for e.g. maven-javadoc-plugin). Now in those modules of your multi module project where you have source code, you just state (without version or configuration) beneath //project/build/plugins/ which plugins to really execute. Drawback: you have to repeat the last step for every JAR and WAR.
2. Version and configure jacoco-maven-plugin, maven-surefire-plugin and maven-failsafe-plugin in //project/profiles/profile/build/plugins of your parent pom and switch on this specific profile by checking for src/main/java for activation. Worked great in our corporate master pom, which all java projects have as uppermost parent (about 1000 projects). As an example see https://github.com/1and1/foss-parent/blob/master/pom.xml#L1085 where this is used to only run checkstyle, pmd and findbugs when src/main/javaexists. Drawback: some people consider profiles to be evil.
3. Probably the cleanest solution: redefine the jar lifecycle by supplying your parent pom an extension jar, see https://github.com/mfriedenhagen/foss-jar-maven-plugin/blob/master/src/main/resources/META-INF/plexus/components.xml for an example how to configure your lifecycle. Create a JAR holding only the components.xml file and use the JAR via //project/build/extensions/extension. Now your parent pom stays clean and all your packaging run the goals you like 😁

While #170 does skip the execution for POMs and EARs, you may easily define other packagings without classes easily. So the best solution would be to check for the existence of target/classes, this would make the fix more independent.

[mfriedenhagen]

@jlupi: I am only able to reproduce your issue by adding a jar project without any classes.

[jlupi]

@mfriedenhagen I do use //project/build/pluginManagement/plugins in the parent pom. Anyway, checking for the existence of target/classes will work for me. For now I'll just skip the module. Thanks.

[mfriedenhagen]

@jlupi: I still do not see, why the report goal runs at all in your EAR. In 0.6.4 there is already a check for the existence of the datafile (

jacoco/jacoco-maven-plugin/src/org/jacoco/maven/AbstractReportMojo.java

Line 155 in 0ad97bb

if (!getDataFile().exists()) {

), which should prevent the report mojo from running. Somehow in your EAR-project the datafile (normally target/jacoco.exec) seems to be created.

[Godin]

@mfriedenhagen I think that reasonable to ask @jlupi for reproducer (small example project) instead of wasting time on guesses ;)

[mfriedenhagen]

@Godin, @marchof: I would like to merge this PR so I can work on #171 and #119.

[marchof]

@mfriedenhagen Looks good to me.