Combining C++ Coverage Results from Parallel stages in a Jenkins Pipeline

Question

I have the following Jenkinsfile:

pipeline{
   stages
   {
      stage ("Compile Everything") {/**/} // Code coverage flags turned on
                                          // Stashes compiled test binaries. 
      stage ("Parallel Tests"){
         parallel{
            stage ("Run Tests A-L") {/**/} // These stages unstash and run groups of tests,
            stage ("Run Tests L-Z") {/**/} // causing coverage files to be created.
                                           // I analyze those coverage files via
                                           // gcovr and stash the results as xml.
         }
      }

      stage ("Combine and Publish Coverage") {/**/} // Here I can unstash all of the xml
                                                    // code coverage files, but don't know
                                                    // how to combine them.
   }
}

In that final stage, "Combine and Publish Coverage" is it possible to combine all of the xml files created by gcovr?

Has anyone solved the problem of testing in parallel and combining coverage results in another way entirely?

Answer 1

The following solution isn't as elegant as I'd like, but the best I can come up with.

Use lcov instead of gcovr to initially generate the coverage reports. This creates .info files which lcov is capable of combining down to a single .info file.

Unstash all .info files from previous stages, then use lcov -a to combine them into a single .info file. (Reference)

Next, use the lcov-to-cobertura converter to convert this .info file into an xml file which can be reported to SonarQube.