PDF output: Pygments error highlighting increases line spacing in code blocks

[jfbu]

Procedure to reproduce the problem

Apply following patch to silence Pygments exception on lexer error token:

diff --git a/sphinx/highlighting.py b/sphinx/highlighting.py
index eb309d82a..acaca89ad 100644
--- a/sphinx/highlighting.py
+++ b/sphinx/highlighting.py
@@ -44,8 +44,8 @@ lexers = dict(
     rest = RstLexer(stripnl=False),
     c = CLexer(stripnl=False),
 )  # type: Dict[unicode, Lexer]
-for _lexer in lexers.values():
-    _lexer.add_filter('raiseonerror')
+# for _lexer in lexers.values():
+#     _lexer.add_filter('raiseonerror')
 
 
 escape_hl_chars = {ord(u'\\'): u'\\PYGZbs{}',
@@ -136,7 +136,8 @@ class PygmentsBridge(object):
                                    location=location)
                     lexer = lexers['none']
                 else:
-                    lexer.add_filter('raiseonerror')
+                    pass
+                    # lexer.add_filter('raiseonerror')
 
         # trim doctest options if wanted
         if isinstance(lexer, PythonConsoleLexer) and self.trim_doctest_flags:

Then do make latexpdf with index.rst being

Welcome to FOO's documentation!
===============================

.. highlight:: coq

.. raw:: latex

   \begin{multicols}2

::

   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).


.. raw:: latex

   \makeatletter
   \def\PYG@tok@err {\def\PYG@bc##1{\strut ##1}}
   \makeatother

::

   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).
   Definition logeq_both_false {X Y : UU} : ¬X -> ¬Y -> (X <-> Y).

.. raw:: latex

   \end{multicols}

and conf.py containing

latex_elements = {
    'preamble': r'\usepackage{multicol}',
}

Error logs / results

This produces this

Expected results

The two sides have the same height.

The problem is in the produced sphinxhighlight.sty file in the latex build repertory which contains

\expandafter\def\csname PYG@tok@err\endcsname{\def\PYG@bc##1{\setlength{\fboxsep}{0pt}\fcolorbox[rgb]{1.00,0.00,0.00}{1,1,1}{\strut ##1}}}

It should be \setlength\fboxsep{-\fboxrule}.

Besides there is another bug, which is that braces should be used else the \fboxsep settting is not local. This does not show easily because each line in code-block is in its own TeX box, so the change does not propagate to other lines, and besides a priori, nothing uses again \fboxsep setting. But it is a bug nevertheless.

There is also

\expandafter\def\csname PYG@tok@cs\endcsname{\def\PYG@tc##1{\textcolor[rgb]{0.25,0.50,0.56}{##1}}\def\PYG@bc##1{\setlength{\fboxsep}{0pt}\colorbox[rgb]{1.00,0.94,0.94}{\strut ##1}}}

which has same unbraced \setlength{\fboxsep}{0pt} issue. (here 0pt is correct choice, though).

Environment info

• OS: Mac
• Python version: 3.5.4
• Sphinx version: stable at 0c98d04
• TeXLive 2017

Relates

#4225

[jfbu]

This appears to a be a bug (or feature) of the Pygments latex formatter, because as far as I understand the sphinxhighlight.sty is generated (from sphinx/builders/latex.py) via a call to Pygments via a PygmentsBridge object (the class is defined in highlighting.py).

[jfbu]

Fixed at 0febbc5