fix: refuse deleting the cwd or its parent

src/longpath/cwdguard.py

@@ -0,0 +1,31 @@
+"""Refuse deletes that would wipe the working directory or its parent."""
+
+from __future__ import annotations
+
+import os
+from typing import Optional
+
+
+def cwd_delete_reason(path: str) -> Optional[str]:
+    """Why *path* must not be deleted, or ``None`` if the cwd guard is silent.
+
+    Root-device refusal stays in :func:`longpath.rm.rm_path` so this only
+    covers the current working directory and its immediate parent.
+    """
+    try:
+        target = os.path.realpath(os.path.abspath(path))
+        cwd = os.path.realpath(os.getcwd())
+    except OSError:
+        return None
+    if os.path.normcase(target) == os.path.normcase(cwd):
+        return "refusing to delete the current working directory"
+    parent = os.path.dirname(cwd)
+    if not parent or os.path.dirname(parent) == parent:
+        return None
+    try:
+        parent_real = os.path.realpath(parent)
+    except OSError:
+        return None
+    if os.path.normcase(target) == os.path.normcase(parent_real):
+        return "refusing to delete the parent of the current working directory"
+    return None

src/longpath/rm.py

@@ -19,6 +19,7 @@
 from typing import List, Tuple
 
 from .core import WINDOWS, displayable, ext_path, safe_walk, unext
+from .cwdguard import cwd_delete_reason
 
 
 @dataclass
@@ -97,6 +98,10 @@ def rm_path(path: str, *, dry_run: bool = False) -> RmResult:
     if os.path.dirname(plain) == plain:
         result.errors.append((plain, "refusing to delete a filesystem root"))
         return result
+    cwd_reason = cwd_delete_reason(plain)
+    if cwd_reason:
+        result.errors.append((plain, cwd_reason))
+        return result
 
     real = ext_path(path)
 

tests/test_rm_cwd.py

@@ -0,0 +1,59 @@
+"""CWD / parent delete guards — separate from --top / py.typed themes."""
+
+from __future__ import annotations
+
+import os
+
+from longpath.cwdguard import cwd_delete_reason
+from longpath.rm import rm_path
+
+from conftest import mkfile, run_cli
+
+
+def test_cwd_delete_reason_for_dot_and_cwd():
+    assert "current working directory" in (cwd_delete_reason(".") or "")
+    assert "current working directory" in (cwd_delete_reason(os.getcwd()) or "")
+
+
+def test_cwd_delete_reason_for_parent():
+    reason = cwd_delete_reason("..")
+    assert reason is not None
+    assert "parent" in reason
+
+
+def test_rm_path_refuses_cwd(tmp_path, monkeypatch):
+    monkeypatch.chdir(tmp_path)
+    mkfile(str(tmp_path / "keep.txt"))
+    result = rm_path(".")
+    assert not result.ok
+    assert "current working directory" in result.errors[0][1]
+    assert (tmp_path / "keep.txt").exists()
+
+
+def test_rm_path_refuses_parent_of_cwd(tmp_path, monkeypatch):
+    child = tmp_path / "child"
+    child.mkdir()
+    mkfile(str(tmp_path / "keep.txt"))
+    monkeypatch.chdir(child)
+    result = rm_path("..")
+    assert not result.ok
+    assert "parent" in result.errors[0][1]
+    assert (tmp_path / "keep.txt").exists()
+
+
+def test_rm_path_still_deletes_sibling(tmp_path, monkeypatch):
+    monkeypatch.chdir(tmp_path)
+    doomed = tmp_path / "doomed"
+    mkfile(str(doomed / "x.txt"))
+    result = rm_path(str(doomed))
+    assert result.ok, result.errors
+    assert not doomed.exists()
+
+
+def test_cli_rm_dot_exits_2(tmp_path, monkeypatch):
+    monkeypatch.chdir(tmp_path)
+    mkfile(str(tmp_path / "keep.txt"))
+    p = run_cli("rm", ".", "-y", cwd=str(tmp_path))
+    assert p.returncode == 2
+    assert "current working directory" in p.stdout + p.stderr
+    assert (tmp_path / "keep.txt").exists()