diff --git a/.github/workflows/ccpp.yml b/.github/workflows/ccpp.yml
index 4073dd6..64a2e5f 100644
--- a/.github/workflows/ccpp.yml
+++ b/.github/workflows/ccpp.yml
@@ -8,7 +8,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v6
+      with:
+        fetch-depth: 0  # test walks commit history; checkout@v6 defaults to a shallow clone
     - name: Install libgit2
       run: sudo apt-get install libgit2-dev
     - name: make