diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 30f2de724d..861f7349a2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -197,6 +197,8 @@ jobs:
         uses: actions/checkout@v3
         with:
           submodules: true
+          # the default is to use a virtual merge commit between the PR and master: just use the PR
+          ref: ${{ github.event.pull_request.head.sha }}
       - name: Install Nix
         uses: cachix/install-nix-action@v18
         with:
diff --git a/.github/workflows/nix-ci.yml b/.github/workflows/nix-ci.yml
index ce3232ac8f..42ef4afe7c 100644
--- a/.github/workflows/nix-ci.yml
+++ b/.github/workflows/nix-ci.yml
@@ -34,6 +34,9 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
+        with:
+          # the default is to use a virtual merge commit between the PR and master: just use the PR
+          ref: ${{ github.event.pull_request.head.sha }}
       - name: Install Nix
         uses: cachix/install-nix-action@v18
         with: