fix(#6240): fall back when test skills symlink is unavailable (#6276)

Fall back to a copytree (with read-only handling) when the test-server fixture can't create the skills symlink on native Windows without SeCreateSymbolicLinkPrivilege (WinError 1314). Test-infra only. Thanks @rodboev. Closes #6240.

tests/conftest.py

@@ -19,6 +19,7 @@ import multiprocessing
 import os
 import pathlib
 import shutil
+import stat
 import subprocess
 import sys
 import time
@@ -884,6 +885,24 @@ def _rmtree_retry(path):
     )
 
 
+def _seed_test_skills(real_skills: pathlib.Path, test_skills: pathlib.Path) -> None:
+    if not real_skills.exists() or test_skills.exists():
+        return
+    try:
+        test_skills.symlink_to(real_skills)
+    except OSError as exc:
+        if not WINDOWS or getattr(exc, "winerror", None) != 1314:
+            raise
+        shutil.copytree(real_skills, test_skills, copy_function=_copy2_readonly)
+
+
+def _copy2_readonly(source: str, destination: str) -> str:
+    copied = shutil.copy2(source, destination)
+    path = pathlib.Path(copied)
+    path.chmod(path.stat().st_mode & ~(stat.S_IWUSR | stat.S_IWGRP | stat.S_IWOTH))
+    return copied
+
+
 # ── Session-scoped test server ────────────────────────────────────────────────
 
 @pytest.fixture(scope="session", autouse=True)
@@ -914,8 +933,7 @@ def test_server():
     # but all write-heavy state stays isolated.
     real_skills  = HERMES_HOME / 'skills'
     test_skills  = TEST_STATE_DIR / 'skills'
-    if real_skills.exists() and not test_skills.exists():
-        test_skills.symlink_to(real_skills)
+    _seed_test_skills(real_skills, test_skills)
 
     # Isolated cron state
     (TEST_STATE_DIR / 'cron').mkdir(parents=True, exist_ok=True)

tests/test_issue1880_profile_scoped_skills.py

@@ -1,11 +1,11 @@
 import json
 import os
 import pathlib
-import shutil
 import urllib.error
 import urllib.parse
 import urllib.request
 
+import tests.conftest as _conftest
 from tests._pytest_port import BASE
 from tests.conftest import requires_agent_modules
 
@@ -20,7 +20,7 @@ def _remove_path(path: pathlib.Path) -> None:
     if path.is_symlink() or path.is_file():
         path.unlink()
     elif path.exists():
-        shutil.rmtree(path)
+        _conftest._rmtree_retry(path)
 
 
 class _IsolatedSkillsDirs:

tests/test_issue6240_windows_skill_symlink_fallback.py

@@ -0,0 +1,122 @@
+from __future__ import annotations
+
+import pathlib
+import stat
+
+import pytest
+
+import tests.conftest as _conftest
+
+
+def _make_skill_tree(root: pathlib.Path) -> None:
+    skill_dir = root / "demo-skill"
+    skill_dir.mkdir(parents=True)
+    (skill_dir / "SKILL.md").write_text("# Demo\n", encoding="utf-8")
+
+
+def _fail_unexpected_call(message: str):
+    def _fail(*_args, **_kwargs):
+        raise AssertionError(message)
+
+    return _fail
+
+
+def _assert_not_writable(path: pathlib.Path) -> None:
+    assert path.stat().st_mode & stat.S_IWUSR == 0
+    assert path.stat().st_mode & stat.S_IWGRP == 0
+    assert path.stat().st_mode & stat.S_IWOTH == 0
+
+
+def test_seed_test_skills_uses_symlink_path_when_available(monkeypatch, tmp_path):
+    real_skills = tmp_path / "real-skills"
+    test_skills = tmp_path / "test-skills"
+    _make_skill_tree(real_skills)
+
+    seen = {}
+
+    def fake_symlink(self, target):
+        seen["args"] = (self, target)
+        self.mkdir(parents=True)
+        (self / "marker.txt").write_text("symlink path", encoding="utf-8")
+
+    monkeypatch.setattr(pathlib.Path, "symlink_to", fake_symlink)
+    monkeypatch.setattr(_conftest.shutil, "copytree", _fail_unexpected_call("copytree should not run"))
+
+    _conftest._seed_test_skills(real_skills, test_skills)
+
+    assert seen["args"] == (test_skills, real_skills)
+    assert (test_skills / "marker.txt").read_text(encoding="utf-8") == "symlink path"
+
+
+def test_seed_test_skills_windows_symlink_error_falls_back_to_copy(monkeypatch, tmp_path):
+    real_skills = tmp_path / "real-skills"
+    test_skills = tmp_path / "test-skills"
+    _make_skill_tree(real_skills)
+    source_skill = real_skills / "demo-skill" / "SKILL.md"
+    source_mode = source_skill.stat().st_mode
+
+    def fail_symlink(self, target):
+        exc = OSError("[WinError 1314] A required privilege is not held by the client")
+        exc.winerror = 1314
+        raise exc
+
+    monkeypatch.setattr(pathlib.Path, "symlink_to", fail_symlink)
+    monkeypatch.setattr(_conftest, "WINDOWS", True)
+
+    _conftest._seed_test_skills(real_skills, test_skills)
+
+    assert test_skills.is_dir()
+    assert not test_skills.is_symlink()
+    copied_skill = test_skills / "demo-skill" / "SKILL.md"
+    assert copied_skill.read_text(encoding="utf-8") == "# Demo\n"
+    assert source_skill.stat().st_mode == source_mode
+    _assert_not_writable(copied_skill)
+    _conftest._rmtree_retry(test_skills)
+    assert not test_skills.exists()
+
+
+def test_seed_test_skills_windows_non_privilege_error_reraises(monkeypatch, tmp_path):
+    real_skills = tmp_path / "real-skills"
+    test_skills = tmp_path / "test-skills"
+    _make_skill_tree(real_skills)
+
+    def fail_symlink(self, target):
+        exc = OSError("unexpected symlink failure")
+        exc.winerror = 5
+        raise exc
+
+    monkeypatch.setattr(pathlib.Path, "symlink_to", fail_symlink)
+    monkeypatch.setattr(_conftest, "WINDOWS", True)
+
+    with pytest.raises(OSError, match="unexpected symlink failure"):
+        _conftest._seed_test_skills(real_skills, test_skills)
+
+
+def test_seed_test_skills_reraises_symlink_error_off_windows(monkeypatch, tmp_path):
+    real_skills = tmp_path / "real-skills"
+    test_skills = tmp_path / "test-skills"
+    _make_skill_tree(real_skills)
+
+    def fail_symlink(self, target):
+        raise OSError("symlink blocked")
+
+    monkeypatch.setattr(pathlib.Path, "symlink_to", fail_symlink)
+    monkeypatch.setattr(_conftest, "WINDOWS", False)
+
+    with pytest.raises(OSError, match="symlink blocked"):
+        _conftest._seed_test_skills(real_skills, test_skills)
+
+
+def test_seed_test_skills_existing_target_is_noop(monkeypatch, tmp_path):
+    real_skills = tmp_path / "real-skills"
+    test_skills = tmp_path / "test-skills"
+    _make_skill_tree(real_skills)
+    test_skills.mkdir()
+    (test_skills / "existing.txt").write_text("keep", encoding="utf-8")
+
+    monkeypatch.setattr(pathlib.Path, "symlink_to", _fail_unexpected_call("symlink_to should not run"))
+    monkeypatch.setattr(_conftest.shutil, "copytree", _fail_unexpected_call("copytree should not run"))
+
+    _conftest._seed_test_skills(real_skills, test_skills)
+
+    assert (test_skills / "existing.txt").read_text(encoding="utf-8") == "keep"