title: TravisCI / Coverity: Warning - No files were emitted
body: <p>I have a medium size github repository for which I configured Travis-CI/Coverity tools. About a month ago my setup had worked just fine: Travis compiled and built my application, and then performed the Coverity scan and I could see the results on my Coverity page.</p>
  <p>However, lately, the Coverity analysis stopped working. I looked through the Travis log files and compared to the old logs when the builds were successful and that's what I found:</p>
  <p>At the end of the log, the failed version contains the next warning:</p>
  <blockquote>
  <p>[WARNING] No files were emitted. This may be due to a problem with your configuration or because no files were actually compiled by your build command.</p>
  <p>Please make sure you have configured the compilers actually used in the compilation.</p>
  <p>For more details, please look at: /home/travis/build/name/repo-name/build/cov-int/build-log.txt</p>
  <p>Extracting SCM data for 0 files...</p>
  <p>...</p>
  </blockquote>
  <p>So, <strong>the Travis builds are passing, but nothing is generated for the Coverity</strong>. I checked my Travis config file and it is identical to the commits when the Coverity builds were successful.</p>
  <p>For the sake of experiment, I cloned my project repository, rolled back to the version when the builds were successful and set up Travis/Coverity for them. And guess what? Same warning! So, the identical setup that worked in the past (about 35 days ago), does not work anymore. Therefore, I make conclusion, something had changed on the part of Travis since it does not generate certain files.</p>
  <p>I was wondering if anyone encountered this issue? and what it could be about? Are there some Travis settings I need to change?</p>
  <p>Some additional info: I use CMake to build my project, and it has two dependencies: Qt and OpenSceneGraph (which I have to install for Travis).</p>
  <p>This is the approximate script of my <code>.travis.yml</code> on my <code>coverity_scan</code> branch:</p>
  <pre><code>language: cpp
  os: linux
  compiler: gcc
  sudo: required
  dist: trusty
  
  addons:
    apt:
      packages:
        - cmake
        - g++-4.8
    coverity_scan:
      project:
        name: &quot;name/project&quot;
        description: &quot;Build submitted via Travis CI&quot;
      notification_email: email@domain.com
      build_command:   &quot;make -j2 VERBOSE=1&quot;
      branch_pattern: coverity_scan
  
  env:
    global:
      - PROJECT_SOURCE=${TRAVIS_BUILD_DIR}/src/
      - PROJECT_BUILD=${TRAVIS_BUILD_DIR}/build/
      # The next declaration is the encrypted COVERITY_SCAN_TOKEN, created
      #   via the &quot;travis encrypt&quot; command using the project repo's public key
     - secure: &quot;...secure...&quot;
  
  before_install:
    # download Qt
    # ...
    # download OpenSceneGraph
    # ...
    # imitate x server
    - export DISPLAY=:99.0
    - /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac -screen 0 1280x1024x16
    - sleep 3
  
  install:
    # install Qt
    - sudo apt-get --yes install qt55base qt55imageformats qt55svg 
    # compiler
    - export CXX=&quot;g++-4.8&quot;
    - export CC=&quot;gcc-4.8&quot;
    # install OpenSceneGraph
    # ...
  
  before_script:
    # Qt location
    # ...
    # OpenSceneGraph variables
    # ...
  
    # create build folder
    - mkdir $PROJECT_BUILD
    - cd $PROJECT_BUILD 
    # cmake command
    - cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/opt/qt54/lib/cmake -DProject_BUILD_TEST=ON -DProject_VERSION=0.0.0 $PROJECT_SOURCE
  
  script:
    - if [[ &quot;${COVERITY_SCAN_BRANCH}&quot; == 1 ]];
      then
        echo &quot;Don't build on coverty_scan branch.&quot;;
        exit 0;
      fi
    # compile everything, if not coverity branch
    - make -j2
    # run unit tests
    # ...
  </code></pre>