Sonar configuration in multimodule maven project using tycho for unit tests and jacoco for coverage - maven

Question

We're using maven to run a sonar analysis and it works well except for the code coverage results with jacoco. We have an eclipse project that uses tycho-surefire-plugin for testing. I've not overriden the argLines properties so solutions involving that line may not be appropiate.
Facts :
Maven structure structure:
parent
master
module 1
module ...
module n
Testing structure:
client.admin (eclipse-plugin packaging)
client.admin.test.fragment (eclipse-test-plugin packaging)
Properties that are correctly set and identified
sonar.junit.reportsPath
sonar.jacoco.reportPath,
sonar.jacoco.itReportPath
sonar.core.codeCoveragePlugin
sonar.language
The main problem is with the following properties
sonar.test
sonar.sources
sonar.java.binaries
As seen in the Testing structure in the client.admin.test.fragment tests are contained in the /src folder and the sources are located in the project client.admin in the /src folder too.
When we run the analysis we get the following error :
[WARN] Coverage information was not collected. Perhaps you forget to include
debug information into compiled classes?
I believe this has to do with the properties sonar.java.binaries that goes looking for the sources in target/classes of the fragment project (client.admin.project) that are in fact located in the host project (client.admin). In the fragment project we've configured sonar.tests and sonar.sources properties so that they call the /src folder of the corresponding projects.
In the sonar Analysis Parameters page there says that only sonar.sources is a maven valid property, sonar.tests and sonar.java.binaries cannot apparently be configured in maven. How then could I attach the binaries to the project. I've tried copying the folder target/classes from the host project but I got the same message. Is there any workaround in maven ?
Edit 1
There is one jacoco.exec file that is generated for the whole project that can be found at the parent folder. This was done configuring the jacoco.destFile and sonar.jacoco.reportPath properties
Jacoco plugin in main pom :
<!-- Jacoco Plugin -->
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<executions>
<execution>
<id>prepare-agent</id>
<goals>
<goal>prepare-agent</goal>
</goals>
<configuration>
<destFile>${sonar.jacoco.reportPath}</destFile>
<append>true</append>
</configuration>
</execution>
<execution>
<id>default-report</id>
<goals>
<goal>report</goal>
</goals>
<configuration>
<dataFile>${sonar.jacoco.reportPath}</dataFile>
<outputDirectory>${jacoco.reports.outputDirectory}</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
Maven Plugin Versions:
sonar: 2.4
jacoco: 0.7.1.201405082137
Properties
<sonar.language>java</sonar.language>
<sonar.core.codeCoveragePlugin>jacoco</sonar.core.codeCoveragePlugin>
<sonar.junit.reportsPath>${project.build.directory}/surefire-reports/</sonar.junit.reportsPath>
<sonar.jacoco.reportPath>${basedir}/../../../main/**.master/target/jacoco.exec</sonar.jacoco.reportPath>
<jacoco.reports.outputDirectory>${basedir}/../../../main/**.master/target/site/jacoco</jacoco.reports.outputDirectory>
<sonar.sources>src</sonar.sources>
In the test projects (eclipse-test-plugin) we changed added the property sonar.sources to go find the sources from the src folder of the project that we're testing for example in client.admin.test.fragment we go search the src from the client.admin
The following properties were commented in code because they're not supported in maven according to documentation and to the debug output.
<!--<sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>-->
<!--<sonar.tests></sonar.tests>-->
<!--<sonar.java.binaries></sonar.java.binaries>-->

Answer 1

First, you must tell the JaCoCo agent to report all coverage data into one common file. Second, you tell the Sonar JaCoCo plugin to read the coverage data from the aggregated file.
To do so, set the properties "jacoco.destFile" and "sonar.jacoco.reportPath" in your parent pom.xml to the same absolute path, e.g.:
<properties>
<jacoco.destFile>/home/jenkins/jobs/my.project/workspace/parent/target/jacoco.exec</jacoco.destFile>
<sonar.jacoco.reportPath>/home/jenkins/jobs/my.project/workspace/parent/target/jacoco.exec</sonar.jacoco.reportPath>
</properties>
Note that these properties will be inherited to all child poms, so you can't use Maven expressions like ${project.build.directory} because this would evaluate to a different directory for each pom.
You could create a small helper Mojo which automatically resolves an absolute path on the current build machine and then injects the properties into the Maven model.