enh: delete legacy cache if it exists

pip_audit/_cache.py

@@ -6,6 +6,7 @@
 
 import logging
 import os
+import shutil
 import subprocess
 import sys
 from pathlib import Path
@@ -29,6 +30,8 @@
 
 _PIP_VERSION = Version(str(pip_api.PIP_VERSION))
 
+_PIP_AUDIT_LEGACY_INTERNAL_CACHE = Path.home() / ".pip-audit-cache"
+
 
 def _get_pip_cache() -> Path:
     # Unless the cache directory is specifically set by the `--cache-dir` option, we try to share
@@ -45,6 +48,14 @@ def _get_pip_cache() -> Path:
     return http_cache_dir
 
 
+def _delete_legacy_cache_dir(current_cache_dir: Path, legacy_cache_dir: Path) -> None:
+    """
+    Deletes the legacy `pip-audit` if it exists.
+    """
+    if current_cache_dir != legacy_cache_dir:
+        shutil.rmtree(legacy_cache_dir)
+
+
 def _get_cache_dir(custom_cache_dir: Path | None, *, use_pip: bool = True) -> Path:
     """
     Returns a directory path suitable for HTTP caching.
@@ -62,6 +73,10 @@ def _get_cache_dir(custom_cache_dir: Path | None, *, use_pip: bool = True) -> Pa
     # Retrieve pip-audit's default internal cache using `platformdirs`.
     pip_audit_cache_dir = user_cache_path("pip-audit", appauthor=False, ensure_exists=True)
 
+    # If the retrieved cache isn't the legacy one, try to delete it.
+    if _PIP_AUDIT_LEGACY_INTERNAL_CACHE.exists():
+        _delete_legacy_cache_dir(pip_audit_cache_dir, _PIP_AUDIT_LEGACY_INTERNAL_CACHE)
+
     # Respect pip's PIP_NO_CACHE_DIR environment setting.
     if use_pip and not os.getenv("PIP_NO_CACHE_DIR"):
         pip_cache_dir = _get_pip_cache() if _PIP_VERSION >= _MINIMUM_PIP_VERSION else None

test/test_cache.py

@@ -9,7 +9,7 @@
 from pytest import MonkeyPatch
 
 import pip_audit._cache as cache
-from pip_audit._cache import _get_cache_dir, _get_pip_cache
+from pip_audit._cache import _delete_legacy_cache_dir, _get_cache_dir, _get_pip_cache
 
 
 def _patch_platformdirs(monkeypatch: MonkeyPatch, sys_platform: str) -> None:
@@ -150,3 +150,13 @@ def test_cache_warns_about_old_pip(monkeypatch, cache_dir):
     # have an old `pip`, then we should expect a warning to be logged
     _get_cache_dir(None)
     assert len(logger.warning.calls) == 1
+
+
+def test_delete_legacy_cache_dir(tmp_path):
+    legacy = tmp_path / "pip-audit-cache"
+    legacy.mkdir()
+    assert legacy.exists()
+
+    current = _get_cache_dir(None, use_pip=False)
+    _delete_legacy_cache_dir(current, legacy)
+    assert not legacy.exists()