ci: avoid python in change detection

.forgejo/workflows/ci.yml

@@ -18,61 +18,44 @@ jobs:
       - id: filter
         name: Detect changes
         run: |
-          python - <<'PY'
-          import json
-          import os
-          import subprocess
-          import sys
+          set -euo pipefail
+          git fetch --quiet --depth=1 origin "${GITHUB_BASE_REF:-}" || true
 
-          event_path = os.environ.get("GITHUB_EVENT_PATH")
-          base = None
-          head = None
-          if event_path and os.path.exists(event_path):
-            with open(event_path, "r", encoding="utf-8") as handle:
-              data = json.load(handle)
-            if "pull_request" in data:
-              base = data["pull_request"]["base"]["sha"]
-              head = data["pull_request"]["head"]["sha"]
-            else:
-              base = data.get("before")
-              head = data.get("after") or data.get("checkout_sha")
+          diff_range=""
+          if [ -n "${GITHUB_BASE_REF:-}" ]; then
+            base_ref="origin/${GITHUB_BASE_REF}"
+            if git rev-parse --verify "$base_ref" >/dev/null 2>&1; then
+              diff_range="$(git merge-base "$base_ref" HEAD)..HEAD"
+            fi
+          else
+            if git rev-parse --verify HEAD^ >/dev/null 2>&1; then
+              diff_range="HEAD^..HEAD"
+            fi
+          fi
 
-          if not head:
-            head = os.environ.get("GITHUB_SHA")
+          if [ -n "$diff_range" ]; then
+            files="$(git diff --name-only "$diff_range")"
+          else
+            files="$(git ls-files)"
+          fi
 
-          if not base or base == "0000000000000000000000000000000000000000":
-            try:
-              subprocess.check_call(
-                ["git", "rev-parse", f"{head}^"],
-                stdout=subprocess.DEVNULL,
-                stderr=subprocess.DEVNULL,
-              )
-              base = f"{head}^"
-            except Exception:
-              base = None
+          backend=false
+          frontend=false
+          while IFS= read -r path; do
+            case "$path" in
+              back001/*|.forgejo/workflows/*|ci/*) backend=true ;;
+            esac
+            case "$path" in
+              front001/*|.forgejo/workflows/*|ci/*) frontend=true ;;
+            esac
+          done <<EOF
+          $files
+          EOF
 
-          if base:
-            diff_cmd = ["git", "diff", "--name-only", base, head]
-          else:
-            diff_cmd = ["git", "ls-files"]
-
-          files = subprocess.check_output(diff_cmd, text=True).splitlines()
-          backend = False
-          frontend = False
-          for path in files:
-            if path.startswith("back001/") or path.startswith(".forgejo/workflows/") or path.startswith("ci/"):
-              backend = True
-            if path.startswith("front001/") or path.startswith(".forgejo/workflows/") or path.startswith("ci/"):
-              frontend = True
-
-          out_path = os.environ.get("GITHUB_OUTPUT")
-          if not out_path:
-            print("GITHUB_OUTPUT not set", file=sys.stderr)
-            sys.exit(1)
-          with open(out_path, "a", encoding="utf-8") as handle:
-            handle.write(f"backend={'true' if backend else 'false'}\n")
-            handle.write(f"frontend={'true' if frontend else 'false'}\n")
-          PY
+          {
+            echo "backend=$backend"
+            echo "frontend=$frontend"
+          } >> "$GITHUB_OUTPUT"
     outputs:
       backend: ${{ steps.filter.outputs.backend }}
       frontend: ${{ steps.filter.outputs.frontend }}