[ci] ensure that upstream mr branches are present

.gitlab-ci/default.yml

@@ -22,23 +22,24 @@ select tests:
   stage: configure
   before_script:
     - |
-      DUMUX_CLONE_BRANCH=master
       if [[ "$DUMUX_PIPELINE_SOURCE" == "merge_request_event" ]]; then
-        echo "Starting pipeline triggered by upstream merge request event"
-        echo "Received upstream merge request branch ${DUMUX_MR_SOURCE_BRANCH}"
-        DUMUX_CLONE_BRANCH=${DUMUX_MR_SOURCE_BRANCH}
+          echo "Cloning upstream merge request source/target branches ${DUMUX_MR_SOURCE_BRANCH}/${DUMUX_MR_TARGET_BRANCH}"
+          git clone -b ${DUMUX_MR_SOURCE_BRANCH} --depth=1 https://git.iws.uni-stuttgart.de/dumux-repositories/dumux.git
+          pushd dumux
+              git fetch --depth=1 origin ${DUMUX_MR_TARGET_BRANCH}:${DUMUX_MR_TARGET_BRANCH}
+          popd
+      else
+          echo "Cloning into Dumux master"
+          git clone -b master --depth 1 https://git.iws.uni-stuttgart.de/dumux-repositories/dumux.git
       fi
-    - echo "Checking out branch ${DUMUX_CLONE_BRANCH} in dumux"
-    - git clone -b ${DUMUX_CLONE_BRANCH} --depth 1 https://git.iws.uni-stuttgart.de/dumux-repositories/dumux.git
     - dunecontrol --opts=$DUNE_OPTS_FILE --only=dumux all
   script:
     - dunecontrol --opts=$DUNE_OPTS_FILE --current all
     - |
-      echo "Check if tests affected by changes have to be identified"
       if [[ "$DUMUX_PIPELINE_SOURCE" == "merge_request_event" ]]; then
           CHECK_FOLDER="dumux"
-          SOURCE_TREE=origin/$DUMUX_MR_SOURCE_BRANCH
-          TARGET_TREE=origin/$DUMUX_MR_TARGET_BRANCH
+          SOURCE_TREE=$DUMUX_MR_SOURCE_BRANCH
+          TARGET_TREE=$DUMUX_MR_TARGET_BRANCH
       elif [[ "$TRIGGER_SOURCE" == "merge_request_event" ]]; then
           CHECK_FOLDER="."
           SOURCE_TREE="HEAD"