[env] fix: Improve License Check Hook Flexibility (#3202)

### What does this PR do?

Solve #3201

#### Problem
The existing license check hook scans all directories recursively from a
single root directory, which causes issues in local development
environments:

* Virtual environments (`.venv`, `venv/`) get scanned and fail license
checks
* No easy way to exclude common build/cache directories without
hardcoding exclusions
* Different behavior between local development (with venvs) and CI/CD
(clean environment)

#### Solution
Modified the `check_license.py` script to accept multiple target
directories instead of a single root directory with exclusions.

### Design & Code Changes
Changed argument from `--directory` to `--directories`
* Now accepts multiple `Path` arguments using `nargs="+"`
* Allows specifying exactly which directories to scan
* in local mode: `--directories examples recipe scripts tests verl
setup.py`
* in github workflow: `--directories .`

.github/workflows/sanity.yml

@@ -12,7 +12,7 @@
 # - `special_sanity`: a suite of quick sanity tests
 # - `special_standalone`: a set of test that are designed to run in dedicated environments
 
-# Accelerators for tests 
+# Accelerators for tests
 # - By default tests are run with GPU available, except for the ones under `special_npu`, and any test script whose name ends with `on_cpu.py`.
 # - For test scripts with `on_cpu.py` name suffix would be tested on CPU resources in linux environment.
 
@@ -78,7 +78,7 @@ jobs:
           pytest -s -x tests/special_sanity
       - name: Run license test
         run: |
-          python3 tests/special_sanity/check_license.py --directory .
+          python3 tests/special_sanity/check_license.py --directories .
       - name: Assert naming convention
         run: |
           if grep -rIn --exclude-dir=.git --exclude-dir=.github --exclude-dir=venv --exclude-dir=__pycache__ 'veRL' .; then

.pre-commit-config.yaml

@@ -32,6 +32,6 @@ repos:
     hooks:
       - id: check-license
         name: Check license
-        entry: python3 tests/special_sanity/check_license.py --directory .
+        entry: python3 tests/special_sanity/check_license.py --directories examples recipe scripts tests verl setup.py
         language: python
         pass_filenames: false

tests/special_sanity/check_license.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 from argparse import ArgumentParser
 from pathlib import Path
+from typing import Iterable
 
 license_head_bytedance = "Copyright 2024 Bytedance Ltd. and/or its affiliates"
 license_head_bytedance_25 = "Copyright 2025 Bytedance Ltd. and/or its affiliates"
@@ -35,13 +36,37 @@ license_headers = [
 ]
 
 
+def get_py_files(path_arg: Path) -> Iterable[Path]:
+    """get py files under a dir. if already py file return it
+
+    Args:
+        path_arg (Path): path to scan for py files
+
+    Returns:
+        Iterable[Path]: list of py files
+    """
+    if path_arg.is_dir():
+        return path_arg.glob("**/*.py")
+    elif path_arg.is_file() and path_arg.suffix == ".py":
+        return [path_arg]
+    return []
+
+
 if __name__ == "__main__":
     parser = ArgumentParser()
-    parser.add_argument("--directory", "-d", required=True, type=str)
+    parser.add_argument(
+        "--directories",
+        "-d",
+        required=True,
+        type=Path,
+        nargs="+",
+        help="List of directories to check for license headers",
+    )
     args = parser.parse_args()
-    directory_in_str = args.directory
 
-    pathlist = Path(directory_in_str).glob("**/*.py")
+    # Collect all Python files from specified directories
+    pathlist = set(path for path_arg in args.directories for path in get_py_files(path_arg))
+
     for path in pathlist:
         # because path is object not string
         path_in_str = str(path.absolute())