Hi Michal,

Em Thu, 6 May 2021 19:48:49 +0200
Michal Suchánek [off-list ref] escreveu:

[  127s] + :
[  127s] + locale
[  128s] LANG=en_US
[  128s] LC_CTYPE="en_US"
[  128s] LC_NUMERIC="en_US"
[  128s] LC_TIME="en_US"
[  128s] LC_COLLATE="en_US"
[  128s] LC_MONETARY="en_US"
[  128s] LC_MESSAGES="en_US"
[  128s] LC_PAPER="en_US"
[  128s] LC_NAME="en_US"
[  128s] LC_ADDRESS="en_US"
[  128s] LC_TELEPHONE="en_US"
[  128s] LC_MEASUREMENT="en_US"
[  128s] LC_IDENTIFICATION="en_US"
[  128s] LC_ALL=
[  128s] + echo LC_ALL=
[  128s] LC_ALL=
[  128s] + echo LANG=en_US
[  128s] LANG=en_US

Where those the locale settings that you used when the build
failed?

I tried to reproduce the bug here with, disabling the parallel run (as
it masks the real error) with both:

	$ for i in LANG LC_ALL LC_ADDRESS LC_IDENTIFICATION LC_MEASUREMENT LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE LC_TIME; do echo $i=en_US; done
	$ make cleandocs && make SPHINXOPTS=-j1 htmldocs

(this one caused lots of warnings on Debian, due to the
 settings at /etc/locale.gen)

and:

	$ for i in LANG LC_ALL LC_ADDRESS LC_IDENTIFICATION LC_MEASUREMENT LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE LC_TIME; do echo $i=en_US.ISO-8859-1; done
	$ make cleandocs && make SPHINXOPTS=-j1 htmldocs

Without any success.

Could you please provide more details about the build VM and the git 
changeset that caused the issue?

Thanks,
Mauro