Undefined control sequence \chapter on ePub -> LaTeX PDF

[adius]

I'm trying to convert the 2. edition of ProGit (https://git-scm.com/book/en/v2) to PDF, but it fails.

~/D/Books $ pandoc --version
pandoc 2.0.2
Compiled with pandoc-types 1.17.3, texmath 0.10, skylighting 0.4.3.2
Default user data directory: /Users/adrian/.pandoc
Copyright (C) 2006-2017 John MacFarlane
Web:  http://pandoc.org
This is free software; see the source for copying conditions.
There is no warranty, not even for merchantability or fitness
for a particular purpose.
~/D/Books $ pandoc \
              --output 2014_progit.pdf \
              2014_progit.epub
[WARNING] Duplicate identifier '_git_p4' at input line 2162 column 24
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
[WARNING] Could not fetch resource 'images/avatars/default.jpg': replacing image with description
Error producing PDF.
! Undefined control sequence.
l.84 \chapter

[mb21]

I can reproduce this with current master:

wget https://github.com/progit/progit2/releases/download/2.1.15/progit.epub
pandoc progit.epub -o progit.pdf

And two minimal examples. Put the following two HTML snippets in an epub file (e.g. generate one with pandoc, then open with vim and edit contained html file).

1. This one produces the \chapter even though the default article class doesn't define the chapter environment.

   <section epub:type="chapter">
     <div>
       <h1>title</h1>
     </div>
   </section>
   

2. And the following is even worse:

   <section epub:type="chapter">
     <h1>title</h1>
   </section>
   

   -t native on it produces the snipped below:

   $ pandoc -f native -t latex
   [Para [Span ("ch001.xhtml",[],[]) []]
   ,Header 0 ("",[],[]) [Str "title"]]
   ^D
   

   which with -t latex gives pandoc: Prelude.init: empty list

[jgm]

Support for chapters was added in 266e197

[jgm]

I don't think any reader should generate level-0 headers.
Maybe @mpickering can offer some insight about why it works this way and how it could be fixed?

[jgm]

I suppose one approach would be to have the HTML/epub reader set some flag in the internal PandocMonad state. This can then be checked (probably in App) and the base header level top level section can be set to "chapter."

With this change, we'd change the HTML reader so that instead of changing header levels when it sees the "chapter" annotation on section, it sets this special flag in the internal PandocMonad state.

[jgm]

@adius as a workaround, you could try adding --top-level-division=chapter to your command line.
(EDIT: you may also need --base-header-level=2.)