[FR] Expand CUSTOM_RULES_DIR to support user relative paths (#5390)

* Add user relative path support

(cherry picked from commit a8dbf2cf16)

detection_rules/config.py

@@ -227,7 +227,7 @@ def parse_rules_config(path: Path | None = None) -> RulesConfig:  # noqa: PLR091
             raise ValueError(f"rules config file does not exist: {path}")
         loaded = yaml.safe_load(path.read_text())
     elif CUSTOM_RULES_DIR:
-        path = Path(CUSTOM_RULES_DIR) / "_config.yaml"
+        path = Path(CUSTOM_RULES_DIR).expanduser() / "_config.yaml"
         if not path.exists():
             raise FileNotFoundError(
                 """

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "detection_rules"
-version = "1.5.18"
+version = "1.5.19"
 description = "Detection Rules is the home for rules used by Elastic Security. This repository is used for the development, maintenance, testing, validation, and release of rules for Elastic Security’s Detection Engine."
 readme = "README.md"
 requires-python = ">=3.12"

tests/base.py

@@ -26,7 +26,7 @@ RULES_CONFIG = parse_rules_config()
 def load_rules() -> RuleCollection:
     if CUSTOM_RULES_DIR:
         rc = RuleCollection()
-        path = Path(CUSTOM_RULES_DIR)
+        path = Path(CUSTOM_RULES_DIR).expanduser()
         assert path.exists(), f"Custom rules directory {path} does not exist"
         rc.load_directories(directories=RULES_CONFIG.rule_dirs)
         rc.freeze()
@@ -62,7 +62,7 @@ class BaseRuleTest(unittest.TestCase):
                 RULE_LOADER_FAIL = True
                 RULE_LOADER_FAIL_MSG = str(e)
 
-        cls.custom_dir = Path(CUSTOM_RULES_DIR).resolve() if CUSTOM_RULES_DIR else None
+        cls.custom_dir = Path(CUSTOM_RULES_DIR).expanduser().resolve() if CUSTOM_RULES_DIR else None
         cls.rules_config = RULES_CONFIG
 
     @staticmethod