ci: add variable PIPELINE_COMMIT_SHA

.gitlab-ci.yml

@@ -14,6 +14,14 @@ workflow:
     # Disable those non-protected push triggered pipelines
     - if: '$CI_COMMIT_REF_NAME != "master" && $CI_COMMIT_BRANCH !~ /^release\/v/ && $CI_COMMIT_TAG !~ /^v\d+\.\d+(\.\d+)?($|-)/ && $CI_PIPELINE_SOURCE == "push"'
       when: never
+    # when running merged result pipelines, it would create a temp commit id. use $CI_MERGE_REQUEST_SOURCE_BRANCH_SHA instead of $CI_COMMIT_SHA.
+    # Please use PIPELINE_COMMIT_SHA at all places that require a commit sha
+    - if: $CI_OPEN_MERGE_REQUESTS != null
+      variables:
+        PIPELINE_COMMIT_SHA: $CI_MERGE_REQUEST_SOURCE_BRANCH_SHA
+    - if: $CI_OPEN_MERGE_REQUESTS == null
+      variables:
+        PIPELINE_COMMIT_SHA: $CI_COMMIT_SHA
     - when: always
 
 variables: