Merge pull request #1752 from ei-grad/unprotect-improvement

unprotect: copy should preceed the move

dvc/repo/unprotect.py

@@ -13,13 +13,16 @@ from dvc.exceptions import DvcException
 def _unprotect_file(path):
     if System.is_symlink(path) or System.is_hardlink(path):
         logger.debug("Unprotecting '{}'".format(path))
-
         tmp = os.path.join(os.path.dirname(path), "." + str(uuid.uuid4()))
-        move(path, tmp)
 
-        copyfile(tmp, path)
+        # The operations order is important here - if some application would
+        # access the file during the process of copyfile then it would get
+        # only the part of file. So, at first, the file should be copied with
+        # the temporary name, and then original file should be replaced by new.
+        copyfile(path, tmp)
+        remove(path)
+        move(tmp, path)
 
-        remove(tmp)
     else:
         logger.debug(
             "Skipping copying for '{}', since it is not "