diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 060d46a2..169135a8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -90,12 +90,12 @@ fedora/csbuild:
   script:
   - |
     if [[ -z "$CI_COMMIT_BEFORE_SHA" ]]; then
-        export CI_COMMIT_BEFORE_SHA=$(git rev-parse HEAD~20)
+        export CI_COMMIT_BEFORE_SHA=$(git rev-parse "${CI_COMMIT_SHA}~20")
     fi
 
     # Check if the commit exists in this branch
     # This is not the case for a force push
-    git branch --contains $CI_COMMIT_BEFORE_SHA 2>/dev/null || export CI_COMMIT_BEFORE_SHA=$(git rev-parse HEAD^)
+    git branch --contains $CI_COMMIT_BEFORE_SHA 2>/dev/null || export CI_COMMIT_BEFORE_SHA=$(git rev-parse "${CI_COMMIT_SHA}~20")
 
     export CI_COMMIT_RANGE="$CI_COMMIT_BEFORE_SHA..$CI_COMMIT_SHA"