Conversion to PDF fails with "TypeError: '<=' not supported between instances of 'str' and 'float'"

[Scott S]

When converting to PDF or other formats, getting the error below, always on "clean edges" as last line of output before the error.

Using Calibre version calibre-5.40.0 on Windows 10. Not sure I can upload an example due to copyrights.

(Edit) The following CSS will generate this error/conversion failure:

margin:auto;

Conversion error...
 File "calibre\utils\ipc\worker.py", line 215, in main
  File "calibre\gui2\convert\gui_conversion.py", line 38, in gui_convert_override
  File "calibre\gui2\convert\gui_conversion.py", line 25, in gui_convert
  File "calibre\ebooks\conversion\plumber.py", line 1239, in run
  File "calibre\ebooks\oeb\transforms\flatcss.py", line 204, in __call__
  File "calibre\ebooks\oeb\transforms\flatcss.py", line 666, in flatten_spine
  File "calibre\ebooks\oeb\transforms\flatcss.py", line 574, in flatten_node
  File "calibre\ebooks\oeb\transforms\flatcss.py", line 493, in flatten_node
  File "calibre\ebooks\oeb\transforms\flatcss.py", line 343, in clean_edges
TypeError: '<=' not supported between instances of 'str' and 'float'

[Kovid Goyal (kovid)]

Fixed in branch master. The fix will be in the next release. calibre is usually released every alternate Friday.

 status fixreleased