Add ASF license header check

.github/workflows/ci.yml

@@ -43,6 +43,9 @@ jobs:
       - name: Validate .asf.yaml
         run: pip install pyyaml -q && python3 tools/validate_asf_yaml.py
 
+      - name: Check ASF license headers
+        run: python3 tools/check_license_headers.py
+
       - name: Install cargo-deny
         uses: taiki-e/install-action@v2
         with:

tools/check_license_headers.py

@@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""Validate ASF license headers on tracked text files."""
+
+from __future__ import annotations
+
+import subprocess
+import sys
+from pathlib import Path
+
+
+ASF_HEADER_TOKEN = "Licensed to the Apache Software Foundation"
+
+EXEMPT_FILES = {
+    "Cargo.lock",
+    "LICENSE",
+    "NOTICE",
+    # Golden test data; adding comments changes the fixture format.
+    "core/tests/fixtures/ivf_flat_v1.hex",
+    "core/tests/fixtures/ivf_hnsw_flat_v1.hex",
+    "core/tests/fixtures/ivf_hnsw_sq_v1.hex",
+    "core/tests/fixtures/ivf_pq_4bit_v1.hex",
+    "core/tests/fixtures/ivf_pq_v1.hex",
+}
+
+
+def repo_root() -> Path:
+    return Path(
+        subprocess.check_output(["git", "rev-parse", "--show-toplevel"], text=True).strip()
+    )
+
+
+def tracked_files(root: Path) -> list[str]:
+    output = subprocess.check_output(["git", "-C", str(root), "ls-files"], text=True)
+    return output.splitlines()
+
+
+def is_text_file(path: Path) -> bool:
+    return b"\0" not in path.read_bytes()
+
+
+def has_asf_header(path: Path) -> bool:
+    lines = path.read_text(encoding="utf-8", errors="replace").splitlines()
+    return ASF_HEADER_TOKEN in "\n".join(lines[:80])
+
+
+def main() -> int:
+    root = repo_root()
+    missing = []
+
+    for file_name in tracked_files(root):
+        if file_name in EXEMPT_FILES:
+            continue
+
+        path = root / file_name
+        if not path.is_file() or not is_text_file(path):
+            continue
+
+        if not has_asf_header(path):
+            missing.append(file_name)
+
+    if missing:
+        print("Files missing ASF license headers:", file=sys.stderr)
+        for file_name in missing:
+            print(f"  {file_name}", file=sys.stderr)
+        return 1
+
+    print("All tracked text files have ASF license headers or are explicitly exempt.")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())