Re: [PATCH] docs: Fix the docs build with Sphinx 6.0

[Akira Yokosawa <akiyks@gmail.com>]

On Wed, 04 Jan 2023 13:45:35 -0700, Jonathan Corbet wrote:
> Sphinx 6.0 removed the execfile_() function, which we use as part of the
> configuration process.  They *did* warn us...  Just open-code the
> functionality as is done in Sphinx itself.
> 
> Tested (using SPHINX_CONF, since this code is only executed with an
> alternative config file) on various Sphinx versions from 2.5 through 6.0.
> 
> Reported-by: Martin Liška <mliska@suse.cz>
> Signed-off-by: Jonathan Corbet <corbet@lwn.net>

I have tested full builds of documentation with this change
with Sphinx versions 1.7.9, 2.4.5, 3.4.3, 4.5.0, 5.3.0, and 6.0.0.

Tested-by: Akira Yokosawa <akiyks@gmail.com>

That said, Sphinx 6.0.0 needs much more time and memory than earlier
versions.

FYI, I needed to limit parallel slot to 2 (make -j2) on a 16GB machine.
If you are lucky, -j3 and -j4 might succeed. -j5 or more ended up in
OOM situations for me:

Comparison of elapsed time and maxresident with -j2:

  ============== ============ ===========
  Sphinx version elapsed time maxresident
  ============== ============ ===========
  5.3.0          10:16.81      937660
  6.0.0          17:29.07     5292392
  ============== ============ ===========

        Thanks, Akira

> ---
>  Documentation/sphinx/load_config.py | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/sphinx/load_config.py b/Documentation/sphinx/load_config.py
> index eeb394b39e2c..8b416bfd75ac 100644
> --- a/Documentation/sphinx/load_config.py
> +++ b/Documentation/sphinx/load_config.py
> @@ -3,7 +3,7 @@
>  
>  import os
>  import sys
> -from sphinx.util.pycompat import execfile_
> +from sphinx.util.osutil import fs_encoding
>  
>  # ------------------------------------------------------------------------------
>  def loadConfig(namespace):
> @@ -48,7 +48,9 @@ def loadConfig(namespace):
>              sys.stdout.write("load additional sphinx-config: %s\n" % config_file)
>              config = namespace.copy()
>              config['__file__'] = config_file
> -            execfile_(config_file, config)
> +            with open(config_file, 'rb') as f:
> +                code = compile(f.read(), fs_encoding, 'exec')
> +                exec(code, config)
>              del config['__file__']
>              namespace.update(config)
>          else:
> -- 
> 2.38.1