Kepub Conversion Issue

[bdub]

Steps to recreate issue:

1) download the the epub3 version of this book:

https://www.gutenberg.org/ebooks/8086.epub3.images

2) add book to Calibre 9.4 on Windows 11

3) convert to kepub

4) edit book: kepub

calibre, version 9.4.0
ERROR: Failed to open book: Failed to open book, click "Show details" for more information.

Traceback (most recent call last):
File "calibre\gui2\tweak_book\job.py", line 33, in run
File "calibre\gui2\tweak_book\boss.py", line 101, in get_container
File "calibre\ebooks\oeb\polish\container.py", line 1635, in get_container
File "calibre\ebooks\oeb\polish\container.py", line 1452, in __init__
File "calibre\ebooks\oeb\polish\kepubify.py", line 526, in unkepubify_container
File "calibre\ebooks\oeb\polish\kepubify.py", line 507, in do_work_in_parallel
File "concurrent\futures\_base.py", line 443, in result
File "concurrent\futures\_base.py", line 395, in __get_result
File "concurrent\futures\thread.py", line 86, in run
File "concurrent\futures\thread.py", line 73, in run
File "calibre\ebooks\oeb\polish\kepubify.py", line 487, in process_path
File "calibre\ebooks\oeb\polish\kepubify.py", line 385, in kepubify_html_path
File "calibre\ebooks\oeb\polish\kepubify.py", line 378, in kepubify_html_data
File "calibre\ebooks\oeb\polish\kepubify.py", line 365, in kepubify_parsed_html
File "calibre\ebooks\oeb\polish\kepubify.py", line 302, in remove_kobo_markup_from_html
File "calibre\ebooks\oeb\polish\kepubify.py", line 285, in remove_kobo_spans
File "calibre\ebooks\oeb\polish\kepubify.py", line 274, in unwrap
TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

[JSWolf]

Download the copy from https://www.mobileread.com/forums/sh...ad.php?t=52490 and use that. It's the same book. But it works because it was hand edited.

[kovidgoyal]

https://github.com/kovidgoyal/calibr...259c6ecebdfd48