fix: Windows portability for os.chown and git-apply CRLF hermeticity

src/repo2rlenv/pipelines/recipes/swe_smith/grade.py

@@ -95,7 +95,13 @@ def validate_submission(workspace: Path, contract: dict) -> None:
         ):
             raise ValueError("Non-Python source assets must remain unchanged")
         if relative not in backups:
-            os.chown(path, 0, 0)
+            # os.chown doesn't exist on Windows. This module only ever runs for
+            # real inside the Linux verifier container (every other path here
+            # is an absolute container path); the guard exists so the tests
+            # that call validate_submission() directly can run on a Windows
+            # host without touching real container-only ownership semantics.
+            if sys.platform != "win32":
+                os.chown(path, 0, 0)
             path.chmod(0o644)
     # Only the verifier's collected copy is cleaned. The learner workspace and
     # archived submission retain their bytes. Validate every path first so a
@@ -126,7 +132,8 @@ def main() -> None:
         return
     with tempfile.TemporaryDirectory(prefix="r2e-grade-") as temporary:
         working = Path(temporary)
-        os.chown(working, 1001, 1001)
+        if sys.platform != "win32":  # os.chown doesn't exist on Windows; see above
+            os.chown(working, 1001, 1001)
         working.chmod(0o700)
         report = working / "results.xml"
         command = [

src/repo2rlenv/tasksmith/source_patch.py

@@ -84,7 +84,10 @@ def reverse_crlf_patch(root: Path, patch: Path) -> bool:
         adapted_path = directory / "source.diff"
         adapted_path.write_bytes(adapted)
         result = subprocess.run(
-            ["git", "apply", "--reverse", str(adapted_path.resolve())],
+            # core.autocrlf=false: `staged` isn't a git repository, so `git apply`
+            # would otherwise fall back to the caller's global config and risk
+            # re-normalizing the exact CRLF bytes this fallback just reconstructed.
+            ["git", "-c", "core.autocrlf=false", "apply", "--reverse", str(adapted_path.resolve())],
             cwd=staged,
             capture_output=True,
             text=True,

src/repo2rlenv/tasksmith/worker.py

@@ -211,9 +211,14 @@ def reverse_source(source: dict, base: Path, output: Path) -> tuple[Path, tuple[
         path.parent.mkdir(parents=True, exist_ok=True)
         shutil.copyfile(base / relative, path)
     patch = output / "source.diff"
-    patch.write_text(source["source_diff"])
+    patch.write_bytes(source["source_diff"].encode())
     try:
-        run(["git", "apply", "--reverse", str(patch)], cwd=defective)
+        # -c core.autocrlf=false: `defective` isn't a git repository, so without
+        # an explicit override `git apply` falls back to the caller's global
+        # config. On a machine with the (very common, Git-for-Windows-default)
+        # `core.autocrlf=true`, that silently rewrites line endings while
+        # applying, corrupting the exact-byte reversal this function promises.
+        run(["git", "-c", "core.autocrlf=false", "apply", "--reverse", str(patch)], cwd=defective)
     except ValueError:
         if not reverse_crlf_patch(defective, patch):
             raise
@@ -277,7 +282,10 @@ def construct(source: dict, profile: Profile, design: Design, ready: dict, outpu
                 "Private supplements require an existing tests/ directory and an unused tasksmith_behavior.py path"
             )
         local = output / "tasksmith_behavior.py"
-        local.write_text(design.additional_tests)
+        # write_bytes, not write_text: this file is re-read as raw bytes below and
+        # shipped verbatim into the bundle; write_text's newline translation would
+        # rewrite LF to the host's line separator (CRLF on Windows) on the way in.
+        local.write_bytes(design.additional_tests.encode())
         additions[extra] = local
         options.test_selectors.append(extra)
         if "tests" not in options.test_paths:

tests/test_repository_source_collection.py

@@ -25,7 +25,9 @@ def source_tree(tmp_path, monkeypatch):
         path = base / name
         path.parent.mkdir(parents=True, exist_ok=True)
         path.write_text(content)
-    monkeypatch.setattr("os.chown", lambda *args: None)
+    # raising=False: os.chown doesn't exist on Windows, unlike POSIX where
+    # this test's whole point is to neutralize it.
+    monkeypatch.setattr("os.chown", lambda *args: None, raising=False)
     return base
 
 

tests/test_tasksmith_added_source.py

@@ -72,7 +72,8 @@ def test_added_modules_are_absent_and_new_helpers_can_be_submitted(tmp_path, mon
     assert Task(task).config.artifacts[0].source == "/workspace/lib"
     contract = json.loads((task / "tests/contract.json").read_text())
     workspace = task / "environment/source"
-    monkeypatch.setattr("os.chown", lambda *args: None)
+    # raising=False: os.chown doesn't exist on Windows.
+    monkeypatch.setattr("os.chown", lambda *args: None, raising=False)
     # Missing new APIs are left to behavioral assertions, not a collection exception.
     validate_submission(workspace, contract)
     (workspace / "lib/helper.py").write_text("value = 1\n")

tests/test_tasksmith_verifier_selection.py

@@ -161,7 +161,8 @@ def test_image(image, options, output, **kwargs):
     monkeypatch.setattr(worker, "reverse_source", lambda *args: (defective, []))
     monkeypatch.setattr(worker, "test_image", test_image)
     monkeypatch.setattr(worker, "test_excerpts", lambda *args, **kwargs: [])
-    monkeypatch.setattr("os.chown", lambda *args: None)
+    # raising=False: os.chown doesn't exist on Windows.
+    monkeypatch.setattr("os.chown", lambda *args: None, raising=False)
     output = tmp_path / "construct"
     output.mkdir()
     result = worker.construct(

tests/test_verifier_editor_backups.py

@@ -3,6 +3,7 @@
 import hashlib
 import os
 import shutil
+import sys
 
 import pytest
 
@@ -14,7 +15,8 @@ def submission(tmp_path, monkeypatch):
     workspace = tmp_path / "private"
     (workspace / "src").mkdir(parents=True)
     (workspace / "src/model.py").write_text("value = 1\n")
-    monkeypatch.setattr("os.chown", lambda *args: None)
+    # raising=False: os.chown doesn't exist on Windows.
+    monkeypatch.setattr("os.chown", lambda *args: None, raising=False)
     contract = {"submitted_files": ["src/model.py"], "submitted_roots": ["src"]}
     return workspace, contract
 
@@ -48,7 +50,20 @@ def test_unknown_non_python_additions_still_reject_without_cleaning(submission,
     assert backup.read_text() == "previous\n"
 
 
-@pytest.mark.parametrize("kind", ["symlink", "dangling_symlink", "oversized", "fifo"])
+@pytest.mark.parametrize(
+    "kind",
+    [
+        "symlink",
+        "dangling_symlink",
+        "oversized",
+        pytest.param(
+            "fifo",
+            marks=pytest.mark.skipif(
+                sys.platform == "win32", reason="os.mkfifo doesn't exist on Windows"
+            ),
+        ),
+    ],
+)
 def test_backup_paths_keep_regular_file_and_symlink_guards(submission, tmp_path, kind):
     workspace, contract = submission
     backup = workspace / "src/model.py.bak"