[ci] R macOS CI jobs failing on 'brew install basictex'

[jameslamb]

Description

For at least the last 24 hours, macOS CI jobs have been failing with the following error:

==> Caveats
You must restart your terminal window for the installation of MacTex CLI tools to take effect.
Alternatively, Bash and Zsh users can run the command:

  eval "$(/usr/libexec/path_helper)"

==> Downloading http://mirror.ctan.org/systems/mac/mactex/mactex-basictex-20210325.pkg
==> Downloading from https://ctan.math.illinois.edu/systems/mac/mactex/mactex-basictex-20210325.pkg
curl: (22) The requested URL returned error: 404 
Error: Download failed on Cask 'basictex' with message: Download failed: http://mirror.ctan.org/systems/mac/mactex/mactex-basictex-20210325.pkg
sudo: tlmgr: command not found
sudo: tlmgr: command not found
installer: Error - the package path specified was invalid: '/Users/runner/work/LightGBM/LightGBM/R.pkg'.

Which comes from here:

LightGBM/.ci/test_r_package.sh

Lines 74 to 77 in d811f3a

	brew install --cask basictex
	export PATH="/Library/TeX/texbin:$PATH"
	sudo tlmgr --verify-repo=none update --self
	sudo tlmgr --verify-repo=none install inconsolata helvetic

This results in the following related error during R CMD check:

* checking PDF version of manual ... � WARNING
LaTeX errors when creating PDF version.
This typically indicates Rd problems.
* checking PDF version of manual without hyperrefs or index ... ERROR
Re-running with no redirection of stdout/stderr.
Hmm ... looks like a package
Error in texi2dvi(file = file, pdf = TRUE, clean = clean, quiet = quiet,  : 
  pdflatex is not available
Error in texi2dvi(file = file, pdf = TRUE, clean = clean, quiet = quiet,  : 
  pdflatex is not available
Error in running tools::texi2pdf()
You may want to clean up by 'rm -Rf /var/folders/24/8k48jl6d249_n_qfxwsl6xvm0000gn/T//RtmpJ2Qw8R/Rd2pdf2a345d471e9'
* checking for non-standard things in the check directory ... NOTE
Found the following files/directories:
  ‘lightgbm-manual.tex’

Reproducible example

Example build from #4811: https://github.com/microsoft/LightGBM/runs/5826112507?check_suite_focus=true.

But this is failing on master and multiple PRs.

This is affecting all macOS R CI jobs.

[jameslamb]

I found a relevant thread: Homebrew/homebrew-cask#121499 (comment)

This seems similar to #3454 which we've seen repeatedly...inconsistencies between TeX installers and the mirrors they hit can lead to errors like this, and it sometimes takes a significant amount of time, on the order of hours or days, for changes to be replicated to all mirrors.

I'll try re-building in an hour or two. I'll also addd a PR to make the R CI jobs fail earlier on such download errors.

[jameslamb]

The tests on #4977 and other recently-rebuilt PRs are now passing, so I think this issue is resolved.

[github-actions]

This issue has been automatically locked since there has not been any recent activity since it was closed.
To start a new related discussion, open a new issue at https://github.com/microsoft/LightGBM/issues
including a reference to this.