Improve error handling for file_path.rmtree()

client/utils/file_path.py

Index: client/utils/file_path.py
diff --git a/client/utils/file_path.py b/client/utils/file_path.py
index 6cb52d1b6eb46e3ccc7d66870519e3ab2c9713df..fd4ba9aa6c55856224536fac7a4a64a8a4551bdd 100644
--- a/client/utils/file_path.py
+++ b/client/utils/file_path.py
@@ -1166,11 +1166,13 @@ def rmtree(root):
   # Now that annoying processes in root are evicted, try again.
   errors = []
   fs.rmtree(root, onerror=lambda *args: errors.append(args))
-  if errors:
-    # There's no hope.
+  if errors and fs.exists(root):

[Vadim Sh., 2017/06/13 20:49:01]

as far as I can tell, this code path is not hit on Linux due to 'raise' on line
1119, so it's not the entire fix

+    # There's no hope: the directory was tried to be removed 4 times. Give up
+    # and raise an exception.
     sys.stderr.write(
         'Failed to delete %s. The following files remain:\n' % root)
-    for _, path, _ in errors:
+    # The same path may be listed multiple times.
+    for path in sorted(set(path for _, path, _ in errors)):
       sys.stderr.write('- %s\n' % path)
     raise errors[0][2][0], errors[0][2][1], errors[0][2][2]
   return False