diff --git a/.github/workflows/build-bake.yaml b/.github/workflows/build-bake.yaml
index 25613e94..a1c999b2 100644
--- a/.github/workflows/build-bake.yaml
+++ b/.github/workflows/build-bake.yaml
@@ -18,7 +18,7 @@ jobs:
       cancel-in-progress: true
 
     outputs:
-      GIT_SHA: ${{ steps.checkout.outputs.sha }}
+      GIT_SHA: ${{ steps.get-git-sha.outputs.GIT_SHA }}
 
     steps:
       - name: Checkout
@@ -29,6 +29,7 @@ jobs:
         run: |
           GIT_SHA=$(git rev-parse --short HEAD)
           echo "GIT_SHA=$GIT_SHA" >> $GITHUB_OUTPUT
+          echo "$GIT_SHA"
 
   base:
     needs: [setup]
diff --git a/docker-bake.hcl b/docker-bake.hcl
index 674b4fbe..ddaf21ad 100644
--- a/docker-bake.hcl
+++ b/docker-bake.hcl
@@ -24,7 +24,7 @@ variable DEFAULT_JUPYTERLAB_VERSION {
 }
 
 variable GIT_SHA {
-    default = ""
+    default = null
 }
 
 function tag_safe_version {