feat: Ensure that filters is not empty

CHANGELOG.md

@@ -7,7 +7,9 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0).
 
 ## Unreleased
 
-Nothing.
+### Added
+
+- Ensure that at least one filter is provided to script (in any mode).
 
 ## [1.0.0](https://github.com/trallnag/filter-pre-commit-hooks/compare/6014a859fec1b8842ea1dc573e096609e61ceecd...v1.0.0) / 2025-01-01
 

src/filter_pre_commit_hooks.py

@@ -23,6 +23,7 @@
 import re
 from argparse import ArgumentParser, BooleanOptionalAction
 from pathlib import Path
+from typing import Literal
 
 VERSION = "1.0.0"
 
@@ -89,6 +90,14 @@
 if __name__ == "__main__":
     args = parser.parse_args()
 
+    config: Path = args.config
+    fail_unknown: bool = args.fail_unknown
+    mode: Literal["id", "tag"] = args.mode
+    filters: list[str] = args.filters
+
+    if not filters:
+        parser.error("No filters provided.")
+
     with open(args.config) as pre_commit_config:
         pre_commit_config_content: str = pre_commit_config.read()
 

tests/test_filter_pre_commit_hooks.py

@@ -25,6 +25,16 @@ def test_get_version() -> None:
     assert result.returncode == 0
 
 
+def test_filter_empty() -> None:
+    """
+    Tests that the script errors when no filters are provided.
+    """
+
+    result = run_with()
+    assert result.returncode != 0
+    assert "No filters provided." in result.stderr
+
+
 def test_unknown_fail_default() -> None:
     """
     Tests that the script by default fails when an unknown hook is specified to