When XPATH assistant is invoked during an HTML conversion always gives back an error.

[LARdT]

When in the process of conversion from a HTML file (ziped by CALIBRE)if you invoke the XPATH assistant buttons you always receive an error. The same ebook file in other format does not produce any problem. For example the very same file saved from WORD as RTF and HTML. Because of this I never use HTML files as origin for conversion, instead I save the file as RTF.

I enclose 2 files: the same book in HTML (what WORD calls "simplified HTML" "html SIMPLIFICADO" in Spanish) and RTF. The first will give an error: (I paste from CALIBRE), the second one not.

ERROR: ERROR: Excepción no contemplada: <b>TypeError</b>:'NoneType' object is unsubscriptable

Traceback (most recent call last):
  File "site-packages\calibre\gui2\convert\regex_builder.py", line 117, in builder
  File "site-packages\calibre\gui2\convert\regex_builder.py", line 59, in __init__
  File "site-packages\calibre\gui2\convert\regex_builder.py", line 86, in select_format
  File "site-packages\calibre\gui2\convert\regex_builder.py", line 90, in open_book
  File "site-packages\calibre\ebooks\oeb\iterator.py", line 179, in __enter__
  File "site-packages\calibre\ebooks\conversion\plumber.py", line 866, in create_oebbook
  File "site-packages\calibre\ebooks\oeb\reader.py", line 71, in __call__
  File "site-packages\calibre\ebooks\oeb\reader.py", line 103, in _read_opf
  File "site-packages\calibre\ebooks\oeb\base.py", line 419, in read
  File "site-packages\calibre\startup.py", line 100, in my_join
  File "ntpath.py", line 73, in join
  File "ntpath.py", line 57, in isabs
  File "ntpath.py", line 125, in splitdrive
TypeError: 'NoneType' object is unsubscriptable

[kovidgoyal]

Fixed in branch trunk. The fix will be in the next release.