Fix problem with deleting temporary folders on Windows (re-created patch #1032)

src/poetry/utils/helpers.py

@@ -3,6 +3,7 @@
 import shutil
 import stat
 import tempfile
+import time
 
 from collections.abc import Mapping
 from contextlib import contextmanager
@@ -22,7 +23,6 @@
 
     from poetry.config.config import Config
 
-
 _canonicalize_regex = re.compile("[-_]+")
 
 
@@ -45,7 +45,7 @@ def temporary_directory(*args: Any, **kwargs: Any) -> Iterator[str]:
 
     yield name
 
-    shutil.rmtree(name, onerror=_del_ro)
+    robust_rmtree(name, onerror=_del_ro)
 
 
 def get_cert(config: "Config", repository_name: str) -> Optional[Path]:
@@ -72,11 +72,34 @@ def _on_rm_error(func: Callable, path: str, exc_info: Exception) -> None:
     func(path)
 
 
+def robust_rmtree(path: str, onerror: Callable = None, max_timeout: float = 1) -> None:
+    """
+    Robustly tries to delete paths.
+    Retries several times if an OSError occurs.
+    If the final attempt fails, the Exception is propagated
+    to the caller.
+    """
+    timeout = 0.001
+    while timeout < max_timeout:
+        try:
+            shutil.rmtree(path)
+            return  # Only hits this on success
+        except OSError:
+            # Increase the timeout and try again
+            time.sleep(timeout)
+            timeout *= 2
+
+    # Final attempt, pass any Exceptions up to caller.
+    shutil.rmtree(path, onerror=onerror)
+
+
 def safe_rmtree(path: str) -> None:
     if Path(path).is_symlink():
         return os.unlink(str(path))
 
-    shutil.rmtree(path, onerror=_on_rm_error)
+    shutil.rmtree(
+        path, onerror=_on_rm_error
+    )  # maybe we could call robust_rmtree here just in case ?
 
 
 def merge_dicts(d1: Dict, d2: Dict) -> None:

tests/utils/test_helpers.py

@@ -1,3 +1,5 @@
+import tempfile
+
 from pathlib import Path
 from typing import TYPE_CHECKING
 
@@ -8,12 +10,38 @@
 from poetry.utils.helpers import canonicalize_name
 from poetry.utils.helpers import get_cert
 from poetry.utils.helpers import get_client_cert
+from src.poetry.utils.helpers import robust_rmtree
 
 
 if TYPE_CHECKING:
     from tests.conftest import Config
 
 
+def test_robust_rmtree(mocker):
+    mocked_rmtree = mocker.patch("shutil.rmtree")
+
+    # this should work after an initial exception
+    name = tempfile.mkdtemp()
+    mocked_rmtree.side_effect = [
+        OSError(
+            "Couldn't delete file yet, waiting for references to clear", "mocked path"
+        ),
+        None,
+    ]
+    robust_rmtree(name)
+
+    # this should give up after retrying multiple times
+    name = tempfile.mkdtemp()
+    mocked_rmtree.side_effect = OSError(
+        "Couldn't delete file yet, this error won't go away after first attempt"
+    )
+    with pytest.raises(OSError):
+        robust_rmtree(name, max_timeout=0.04)
+
+    # clear the side effect (breaks the tear-down otherwise)
+    mocked_rmtree.side_effect = None
+
+
 def test_parse_requires():
     requires = """\
 jsonschema>=2.6.0.0,<3.0.0.0