Bug#998059: sphinx: LANGUAGE environement variable inconsistently affects output of objects.inv

[Chris Lamb]

Package: sphinx
Version: 4.2.0-5
Severity: normal
User: reproducible-builds at lists.alioth.debian.org
Usertags: toolchain
X-Debbugs-Cc: reproducible-bugs at lists.alioth.debian.org

Hi,

An update has rendered a lot of packages that use Sphinx
unreproducible — as in, generating different output regardless of
the surrounding environment.

I'm not entirely sure where the bug is here, but it seems like there is
something up with language handling and generating the objects.inv
file.

In particular, if we compare a 'first' build with LANGUAGE="en_GB:en"
and the 'second' with LANGUAGE="et_EE:et" environment variable, what
happens is that all of the documentation is identical *except* a
single entry in the objects.inv file which appears to be translated.

Decoding the zlib-encoded objects.inv file, I can see that the
difference is a translation one:

  # Sphinx inventory version 2
  # Project: OpenDrop
  # Version: 
  # The remainder of this file is compressed using zlib.

  developers/index std:doc -1 developers/index.html Developer notes
  -genindex std:label -1 genindex.html Index
  +genindex std:label -1 genindex.html Indeks
  getting_started/index std:doc -1 getting_started/index.html Getting Started
  index std:doc -1 index.html Overview
  modindex std:label -1 py-modindex.html Module Index
  py-modindex std:label -1 py-modindex.html Python Module Index

This is despite the output including the following logging message in
both builds:

  dumping search index in English (code: en)... done
  dumping object inventory... done

(Note the "code: en" here in both builds)

The curious thing is why 'Indeks' was translated and not, for
instance, 'Module Index'. Indeed, I've dumped some more info upstream
here, but filing a Debian bug as, as mentioned, it's causing a lot of
reproducibility issues.

  https://github.com/sphinx-doc/sphinx/issues/9778


Regards,

-- 
      ,''`.
     : :'  :     Chris Lamb
     `. `'`      lamby at debian.org / chris-lamb.co.uk
       `-