diff --git a/.gitea/workflows/quality.yaml b/.gitea/workflows/quality.yaml
index 30c4b01..e67dae8 100644
--- a/.gitea/workflows/quality.yaml
+++ b/.gitea/workflows/quality.yaml
@@ -38,14 +38,11 @@ jobs:
       api:    ${{ steps.detect.outputs.api }}
       docker: ${{ steps.detect.outputs.docker }}
     steps:
-      - if: ${{ inputs.is_pull_request }}
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
+          # Push may contain several commits; github.event.before is then
+          # more than one parent away. fetch-depth: 2 only has HEAD~1.
           fetch-depth: 0
-      - if: ${{ inputs.is_pull_request == false }}
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          fetch-depth: 2
       - id: detect
         name: Detect changed paths per module
         env:
@@ -72,12 +69,16 @@ jobs:
             done
           }
 
+          has_commit() {
+            git cat-file -e "${1}^{commit}" 2>/dev/null
+          }
+
           if [ "$IS_PR" = "true" ]; then
             FILES="$(git diff --name-only "$BASE_SHA" "$HEAD_SHA")"
           else
             after="${HEAD_SHA:-$(git rev-parse HEAD)}"
             before="$BEFORE_SHA"
-            if [ -n "$before" ] && [ "$before" != "0000000000000000000000000000000000000000" ]; then
+            if [ -n "$before" ] && [ "$before" != "0000000000000000000000000000000000000000" ] && has_commit "$before"; then
               FILES="$(git diff --name-only "$before" "$after")"
             elif git rev-parse --verify HEAD~1 >/dev/null 2>&1; then
               FILES="$(git diff --name-only HEAD~1 HEAD)"