improve CI pipelines for branches

.gitlab-ci.yml

@@ -6,14 +6,12 @@ workflow:
   rules:
     - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
       variables:
-        BASE_COMMIT: $CI_MERGE_REQUEST_DIFF_BASE_SHA
-        TIP_COMMIT: $CI_COMMIT_SHA
+        TARGET_BRANCH: $CI_MERGE_REQUEST_TARGET_BRANCH_NAME
     - if: '$CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS'
       when: never
     - if: '$CI_COMMIT_BRANCH'
       variables:
-        BASE_COMMIT: $CI_COMMIT_BEFORE_SHA
-        TIP_COMMIT: $CI_COMMIT_SHA
+        TARGET_BRANCH: 2022
 
 check_style:
   script:
@@ -31,6 +29,8 @@ check_style:
     - done
     - export EASYBUILD_MODULE_NAMING_SCHEME="FlexibleCustomHierarchicalMNS"
     - faulty=""
+    - export TIP_COMMIT=$CI_COMMIT_SHA
+    - export BASE_COMMIT=$(git merge-base "$TIP_COMMIT" "origin/$TARGET_BRANCH")
     - printf "Checking changes between base %s (%s) and tip %s (%s)\n" "$BASE_COMMIT" "$(git describe --all --exclude pipeline/* $BASE_COMMIT 2> /dev/null)" "$TIP_COMMIT" "$(git describe --all --exclude pipeline/* $TIP_COMMIT 2> /dev/null)"
     - eb_list=$(git diff-tree --no-commit-id -r "$BASE_COMMIT" "$TIP_COMMIT" | awk '$5 ~ /^M|^A/ && $6 ~ /eb$/ {print($6)}')
     - echo "List of files to be checked $eb_list"