diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1f5852c..16b0dde 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -101,6 +101,7 @@ jobs:
       - id: get-main-branch
         name: Determine main branch
         run: |
+          mainBranch=$(git symbolic-ref refs/remotes/origin/HEAD | cut -d '/' -f 4)
           mainBranchHeadRevision=$(git rev-parse refs/remotes/origin/${mainBranch})
           echo "::set-output name=mainBranchHeadRevision::$mainBranchHeadRevision"