Add test of the file type

We don't want to have files with dos CRLF line endings in the repository,
so we test if any of the changed files has this file type.

.gitlab-ci.yml

 stages:
   - checkRepository
-
+  - checkFormat
+  
 RebaseCheck:
   stage: checkRepository
   image: alpine
@@ -60,3 +61,21 @@ LinearHistCheck:
     -   echo "${count} merge commits must be removed or the other new commits have to be replayed in a new branch"
     -   exit 1
     - fi
+
+FileFormatCheck:
+  stage: checkFormat
+  image: alpine
+  tags:
+    - docker
+  only:
+    refs:
+      - merge_requests
+    variables:
+      - $CI_MERGE_REQUEST_PROJECT_PATH == "CbmSoft/cbmroot_geometry" && $CI_MERGE_REQUEST_TARGET_BRANCH_NAME == "master"
+  script:
+    # Get the upstream repository manually. I did not find any other way to have it for
+    # comparison
+    - apk update && apk add git bash file
+    - ci_scripts/connect_upstream_repo.sh $CI_MERGE_REQUEST_PROJECT_URL
+    - git fetch upstream
+    - ci_scripts/check-file-format.sh upstream

ci_scripts/check-file-format.sh

+#!/bin/bash
+
+if [[ $# -eq 1 ]]; then
+  UPSTREAM=$1
+else
+  if [ -z $UPSTREAM ]; then
+    UPSTREAM=$(git remote -v | grep git.cbm.gsi.de[:/]computing/cbmroot | cut -f1 | uniq)
+    if [ -z $UPSTREAM ]; then
+      echo "Error: Name of upstream repository not provided and not found by automatic means"
+      echo 'Please provide if by checking your remotes with "git remote -v" and exporting UPSTREAM'
+      echo "or passing as an argument"
+      exit -1
+    fi
+  fi
+fi
+
+BASE_COMMIT=$UPSTREAM/master
+CHANGED_FILES=$(git diff --name-only $BASE_COMMIT)
+for file in $CHANGED_FILES; do
+  result=$(file $file | grep CRLF)
+  if [[ "$result" != "" ]]; then
+    echo ""
+    echo "File $file has wrong file format"
+    echo "$result"
+    echo ""
+    okay=false
+  fi
+done
+if [[ "$okay" = "false" ]]; then
+  echo ""
+  echo "Not all files have the correct file format"
+  echo "Test failed"
+  exit 1
+else
+  exit 0
+fi
+