Fix #4739 (Setting author_sort to the same as author)

resources/default_tweaks.py

@@ -16,3 +16,12 @@ defaults.
 # next - Next available number
 # const - Assign the number 1 always
 series_index_auto_increment = 'next'
+
+
+
+# The algorithm used to copy author to author_sort
+# Possible values are:
+#  invert: use "fn ln" -> "ln, fn" (the original algorithm)
+#  copy  : copy author to author_sort without modification
+#  comma : use 'copy' if there is a ',' in the name, otherwise use 'invert'
+author_sort_copy_method = 'invert'

src/calibre/ebooks/metadata/__init__.py

@@ -10,9 +10,10 @@ import os, mimetypes, sys, re
 from urllib import unquote, quote
 from urlparse import urlparse
 
-
 from calibre import relpath
 
+from calibre.utils.config import tweaks
+
 _author_pat = re.compile(',?\s+(and|with)\s+', re.IGNORECASE)
 def string_to_authors(raw):
     raw = raw.replace('&&', u'\uffff')
@@ -27,6 +28,9 @@ def authors_to_string(authors):
         return ''
 
 def author_to_author_sort(author):
+    method = tweaks['author_sort_copy_method']
+    if method == 'copy' or (method == 'comma' and author.count(',') > 0):
+        return author
     tokens = author.split()
     tokens = tokens[-1:] + tokens[:-1]
     if len(tokens) > 1: