Use posix paths for Docker exec (#684)

* Use posix paths for Docker exec

* Update CHANGELOG.md

---------

Co-authored-by: jjallaire <[email protected]>

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Fix memory leak in Inspect View worker-based JSON parsing.
 - Add `fail_on_error` option for `eval_retry()` and `inspect eval-retry`.
 - Defer resolving helper models in `self_critique()` and `model_graded_qa()`.
+- Fix Docker relative path resolution on Windows (use PurePosixPath not Path)
 
 ## v0.3.40 (6 October 2024)
 

src/inspect_ai/util/_sandbox/docker/docker.py

@@ -2,7 +2,7 @@
 import os
 import tempfile
 from logging import getLogger
-from pathlib import Path
+from pathlib import Path, PurePosixPath
 from typing import Literal, Union, cast, overload
 
 import aiofiles
@@ -212,7 +212,7 @@ async def exec(
         # additional args
         args = []
 
-        final_cwd = Path(self._working_dir if cwd is None else cwd)
+        final_cwd = PurePosixPath(self._working_dir if cwd is None else cwd)
         if not final_cwd.is_absolute():
             final_cwd = self._working_dir / final_cwd