exp: subclass tempfile.TemporaryDirectory to handle cleanup (#5598)

* exp: subclass tempfile.TemporaryDirectory to handle cleanup

* override cleanup() since cls._rmtree does not exist in <3.8

dvc/repo/experiments/executor/local.py

@@ -3,13 +3,29 @@ import os
 from tempfile import TemporaryDirectory
 from typing import Optional
 
-from dvc.utils.fs import remove
-
 from .base import BaseExecutor
 
 logger = logging.getLogger(__name__)
 
 
+class ExpTemporaryDirectory(TemporaryDirectory):
+    # Python's TemporaryDirectory cleanup shutil.rmtree wrapper does not handle
+    # git read-only dirs cleanly in Windows on Python <3.8, so we use our own
+    # remove(). See:
+    # https://github.com/iterative/dvc/pull/5425
+    # https://bugs.python.org/issue26660
+
+    @classmethod
+    def _rmtree(cls, name):
+        from dvc.utils.fs import remove
+
+        remove(name)
+
+    def cleanup(self):
+        if self._finalizer.detach():
+            self._rmtree(self.name)
+
+
 class BaseLocalExecutor(BaseExecutor):
     """Base local machine executor."""
 
@@ -37,7 +53,7 @@ class TempDirExecutor(BaseLocalExecutor):
         cache_dir: Optional[str] = None,
         **kwargs,
     ):
-        self._tmp_dir = TemporaryDirectory(dir=tmp_dir)
+        self._tmp_dir = ExpTemporaryDirectory(dir=tmp_dir)
         kwargs["root_dir"] = self._tmp_dir.name
         super().__init__(*args, **kwargs)
         if cache_dir:
@@ -55,4 +71,4 @@ class TempDirExecutor(BaseLocalExecutor):
     def cleanup(self):
         super().cleanup()
         logger.debug("Removing tmpdir '%s'", self._tmp_dir)
-        remove(self._tmp_dir.name)
+        self._tmp_dir.cleanup()