bpo-39327: Close file descriptors as soon as possible in shutil.rmtree (GH-31384)

It fixes the "Text File Busy" OSError when using 'rmtree' on a
windows-managed filesystem in via the VirtualBox shared folder
(and possible other scenarios like a windows-managed network file
system).
(cherry picked from commit b77158b)

Co-authored-by: Lital Natan <[email protected]>

Author: miss-islington

Lib/shutil.py

@@ -656,13 +656,16 @@ def _rmtree_safe_fd(topfd, path, onerror):
         if is_dir:
             try:
                 dirfd = os.open(entry.name, os.O_RDONLY, dir_fd=topfd)
+                dirfd_closed = False
             except OSError:
                 onerror(os.open, fullname, sys.exc_info())
             else:
                 try:
                     if os.path.samestat(orig_st, os.fstat(dirfd)):
                         _rmtree_safe_fd(dirfd, fullname, onerror)
                         try:
+                            os.close(dirfd)
+                            dirfd_closed = True
                             os.rmdir(entry.name, dir_fd=topfd)
                         except OSError:
                             onerror(os.rmdir, fullname, sys.exc_info())
@@ -676,7 +679,8 @@ def _rmtree_safe_fd(topfd, path, onerror):
                         except OSError:
                             onerror(os.path.islink, fullname, sys.exc_info())
                 finally:
-                    os.close(dirfd)
+                    if not dirfd_closed:
+                        os.close(dirfd)
         else:
             try:
                 os.unlink(entry.name, dir_fd=topfd)
@@ -719,13 +723,16 @@ def onerror(*args):
             return
         try:
             fd = os.open(path, os.O_RDONLY)
+            fd_closed = False
         except Exception:
             onerror(os.open, path, sys.exc_info())
             return
         try:
             if os.path.samestat(orig_st, os.fstat(fd)):
                 _rmtree_safe_fd(fd, path, onerror)
                 try:
+                    os.close(fd)
+                    fd_closed = True
                     os.rmdir(path)
                 except OSError:
                     onerror(os.rmdir, path, sys.exc_info())
@@ -736,7 +743,8 @@ def onerror(*args):
                 except OSError:
                     onerror(os.path.islink, path, sys.exc_info())
         finally:
-            os.close(fd)
+            if not fd_closed:
+                os.close(fd)
     else:
         try:
             if _rmtree_islink(path):

Misc/ACKS

@@ -418,6 +418,7 @@ Caleb Deveraux
 Catherine Devlin
 Scott Dial
 Alon Diamant
+Lital Natan
 Toby Dickenson
 Mark Dickinson
 Jack Diederich

Misc/NEWS.d/next/Library/2022-02-17-13-10-50.bpo-39327.ytIT7Z.rst

@@ -0,0 +1,2 @@
+:func:`shutil.rmtree` can now work with VirtualBox shared  folders when
+running from the guest operating-system.