diff --git a/.github/workflows/gen_matrix.py b/.github/workflows/gen_matrix.py
index 1244f65..e6c8ce2 100644
--- a/.github/workflows/gen_matrix.py
+++ b/.github/workflows/gen_matrix.py
@@ -6,7 +6,7 @@
 changed_files = json.loads(sys.argv[1])
 for file in changed_files:
     path = Path(file)
-    print(path)
+    print(path, file=sys.stderr)
 
 includes.append({"dir": "2023", "target": "day01"})
 includes.append({"dir": "2023", "target": "day02"})
diff --git a/.github/workflows/test-build.yml b/.github/workflows/test-build.yml
index aabab37..5a2fe97 100644
--- a/.github/workflows/test-build.yml
+++ b/.github/workflows/test-build.yml
@@ -28,7 +28,9 @@ jobs:
       # reference: https://stackoverflow.com/a/65094398
       - name: Setup matrix combinations
         id: setup-matrix-combinations
-        run: python ${GITHUB_WORKSPACE}/.github/workflows/gen_matrix.py "${{ steps.changed-files.outputs.all_changed_files }}" >> $GITHUB_OUTPUT
+        run: |
+          python ${GITHUB_WORKSPACE}/.github/workflows/gen_matrix.py "${{ steps.changed-files.outputs.all_changed_files }}" >> $GITHUB_OUTPUT
+          cat $GITHUB_OUTPUT
 
     outputs:
       matrix-combinations: ${{ steps.setup-matrix-combinations.outputs.matrix-combinations }}
@@ -42,7 +44,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
         with:
-          fetch-depth: 0
+          fetch-depth: 1
 
       - name: Install dependencies
         run: |