sphinxmaketitle should use \linewidth not \textwidth for his ruler

[LuisBL]

Describe the bug

If we configure latepdf to be twocolum with this in conf.py:

latex_elements = {  
    'classoptions': ',twocolumn',    # to have two columns 
    }  

we got twocolumn in _build/latex/proj.tex

  %% Generated by Sphinx.    
  \def\sphinxdocclass{article}
  \documentclass[a4paper,10pt,twocolumn,french]{sphinxhowto}

It work well but the

How to Reproduce

$ python3 -m venv ~/venv ; . ~/venv/bin/activate 
$ pip install sphinx
$ sphinx-quickstart    # answer default to all questions      

To have laxtex A4, article with control on margins and 2 columns: add this to conf.py:

    # -- Options for LaTeX output --------------------------------
    latex_elements = {    
      'papersize': 'a4paper',  # 'letterpaper' or 'a4paper'      
      'pointsize': '10pt',     # font size (default is 10pt)
      'sphinxsetup': 'hmargin={1.5cm,1.5cm}, vmargin={2cm,2cm}', 
      'classoptions': ',twocolumn',    # to have two columns 
      }    
    latex_theme = 'howto'  # 'manual' to make a book, 'howto' to make an article 

Crate some rst files::

    $ mkdir -p src 
    $ vim src/antiquite.rst src/ src/moderne.rst  

Then we need to define the main TOC table of content in the main index.rst file, this TOC file will refer to rst files to include in the document::

    $ cat index.rst    
    Exposé 
    ===============

    .. toctree::      
       :maxdepth: 3      
       :caption: Table des Matieres:   
                                                                                                      
       /src/antiquite.rst
       /src/moderne.rst 
    $     

call:

$ make pdflatex`
$ evince _build/latex/proj.pdf

Expected behavior

the ruller maketitle should not take all the width but only the column widht

Your project

https://github.com/sphinx-doc/sphinx/

Screenshots

OS

Linux Ubuntu 20.04

Python version

Python 3.8.10

Sphinx version

4.3.2

Sphinx extensions

No response

Extra tools

No response

Additional context

No response

[LuisBL]

This patch work well to fix the problem:

(venv) luis@spinoza:~/proj/g/alien/sphinx/sphinx/texinputs$ git diff
diff --git a/sphinx/texinputs/sphinxhowto.cls b/sphinx/texinputs/sphinxhowto.cls
index 951cf810d..5b19e8284 100644
--- a/sphinx/texinputs/sphinxhowto.cls
+++ b/sphinx/texinputs/sphinxhowto.cls
@@ -42,7 +42,7 @@
 % ``Bjarne'' style a bit better.
 %
 \newcommand{\sphinxmaketitle}{%
-  \noindent\rule{\textwidth}{1pt}\par
+    \noindent\rule{\linewidth}{1pt}\par
     \begingroup % for PDF information dictionary
        \def\endgraf{ }\def\and{\& }%
        \pdfstringdefDisableCommands{\def\\{, }}% overwrite hyperref setup
@@ -74,7 +74,7 @@
     \sphinxtableofcontentshook
     \tableofcontents
   \endgroup
-  \noindent\rule{\textwidth}{1pt}\par
+  \noindent\rule{\linewidth}{1pt}\par
   \vspace{12pt}%
 }
 \newcommand\sphinxtableofcontentshook{}
(venv) luis@spinoza:~/proj/g/alien/sphinx/sphinx/texinputs$