LaTeX: framed coloured boxes in highlighted code (e.g. highlighted diffs using Pygments style 'manni') inherit thickness of code-block frame

[jfbu]

Describe the bug

How to Reproduce

.. code-block:: diff

   diff --git a/sphinx/texinputs/sphinx.sty b/sphinx/texinputs/sphinx.sty
   index b67722c1b..33164755b 100644
   --- a/sphinx/texinputs/sphinx.sty
   +++ b/sphinx/texinputs/sphinx.sty
   @@ -6,7 +6,7 @@
    %
    
    \NeedsTeXFormat{LaTeX2e}[1995/12/01]
   -\ProvidesPackage{sphinx}[2022/06/30 v5.1.0 LaTeX package (Sphinx markup)]
   +\ProvidesPackage{sphinx}[2022/07/04 v5.1.0 LaTeX package (Sphinx markup)]
    
    % provides \ltx@ifundefined
    % (many packages load ltxcmds: graphicx does for pdftex and lualatex but

and this in conf.py:

latex_elements = {
    'sphinxsetup': 'verbatimborder=5pt',
}
pygments_style = 'manni'

Expected behavior

Diff lines get not ovewritten by border

Your project

See example

Screenshots

See above

OS

Mac

Python version

3.10.4

Sphinx version

5.0.0

Sphinx extensions

No response

Extra tools

No response

Additional context

Cause of this is that the Sphinx LaTeX sets the \fboxrule length to the configured frame width. But in rare cases, the Pygments highlighter may use \fcolorbox which uses \fboxrule current value. This is what happens here. More often Pygments style may use \colorbox which depends on \fboxsep which is also modified during duration of rendering a code-block. But in all cases, Pygments LaTeX styling sets \fboxsep to zero so there is no trouble there.

[jfbu]

I reopened (without testing first) because I thought, while I was reviewing the codebase, that if the code-block was inside a warning-type notice directive the problem could be there still, as the code sets \fboxrule but in fact no, this \fboxrule setting is not visible by the syntax highlighting (because it is done at a place the syntax highlighting has already been transformed into TeX boxes). So closing ...