diff --git a/action.yaml b/action.yaml
index 3b8f99a..aa509e4 100644
--- a/action.yaml
+++ b/action.yaml
@@ -63,6 +63,10 @@ inputs:
   artifact-name:
     type: string
     description: Name of artifact to upload, defaults to the autobuild package name
+  shallow:
+    type: boolean
+    description: Use shallow clone
+    default: false
 
 outputs:
   package-name:
@@ -87,18 +91,18 @@ runs:
   steps:
     - name: Disable autocrlf
       shell: bash
-      env:
-        WINDOWS: ${{ runner.os == 'Windows' }}
-      run: |
-        if [[ $WINDOWS == 'true' ]]; then
-          git config --global core.autocrlf input
-        fi
+      if: runner.os == 'Windows'
+      run: git config --global core.autocrlf input
 
     - name: Checkout
       uses: actions/checkout@v4
       if: inputs.checkout
       with:
-        fetch-depth: 0 # Fetch all history for SCM version
+        # Work around the fact that in the context of a pull request github.sha
+        # references a dynamic merge commit rather than the branch head
+        # https://frontside.com/blog/2020-05-26-github-actions-pull_request/#how-does-pull_request-affect-actionscheckout
+        ref: ${{ github.event.pull_request.head.sha || github.sha }}
+        fetch-depth: ${{ fromJSON(inputs.shallow) && 1 || 0 }} # Fetch all history for SCM version
         submodules: recursive
 
     - name: Create short SHA