SonarQube: Coverage incomplete on multimodule gradle project with JaCoCo

Question

I am building a SonarQube 6.2 server which is already analyzing my Java 8/Gradle 3.3 projects. When adding JaCoCo to a multimodule gradle project, I realized that SonarQube

Answer 1

When you perform build JaCoCo Gradle Plugin will produce modA/build/jacoco/test.exec and modB/build/jacoco/test.exe that contain information about execution of tests in modA and modB respectively. SonarQube performs analysis of modules separately, so during analysis of modA for the file TestedViaModB it sees only modA/build/jacoco/test.exec.

Most common trick to cross boundaries - is to collect all coverage information into single location. This can be done with JaCoCo Gralde Plugin

• either by changing location - see destinationFile and destPath ( since information is appended to exec file, don't forget to remove this single location prior to build, otherwise it will be accumulating information from different builds and not just from different modules ),

• either by merging all files into single one - see JacocoMerge task. And then specify this single location to SonarQube as sonar.jacoco.reportPath.

Another trick: SonarQube 6.2 with Java Plugin 4.4 supports property sonar.jacoco.reportPaths allowing to specify multiple locations.

Answer 2

If you are interested in the solution with sonar.jacoco.reportPaths (see answer of Godin), have looke at this gradle code:

tasks.getByName('sonarqube') {
    doFirst {
        // lazy initialize the property to collect all coverage files
        def jacocoFilesFromSubprojects = subprojects.findAll {it.plugins.hasPlugin('jacoco')}
                .collect {it.tasks.withType(Test)}.flatten().collect {it.jacoco.destinationFile}

        sonarqube.properties {
            property "sonar.jacoco.reportPaths", jacocoFilesFromSubprojects.join(',')
        }
    }
}

This will collect all coverage binary files and set them as comma-separated list to the sonar property. Considers all test tasks of sub projects where jacoco is applied and their jacoco destination file configured.