[BUG] rspamd v3.8.0 fails to start with lua 5-1 (works with lua 5-3 and lua 5-4)

[erialor]

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Read about bug reporting in general: https://rspamd.com/doc/faq.html#how-to-report-bugs-found-in-rspamd
  • Enabled relevant debugging logs: https://rspamd.com/doc/faq.html#how-to-debug-some-module-in-rspamd
  • Checked the FAQs about Core files in case of fatal crash: https://rspamd.com/doc/faq.html#how-to-figure-out-why-rspamd-process-crashed
  • Tried ASAN package and obtained the ASAN report (if possible): https://rspamd.com/doc/faq.html#asan-builds
  • Checked that your issue isn't already filed: https://github.com/issues?utf8=%E2%9C%93&q=is%3Aissue+user%3Arspamd
  • Checked that there is not already an experimental package or master branch

Describe the bug
rspamd fail to start when using lua 5-1 with:

mail ~ # /etc/init.d/rspamd start
rcl parse error: cannot init lua file /usr/share/rspamd/rules/rspamd.lua: error loading module 'lua_maps' from file '/usr/share/rspamd/lualib/lua_maps.lua':
/usr/share/rspamd/lualib/lua_maps.lua:564: nesting of [[...]] is deprecated near '['; trace: [1]:{[C]:-1 - [C]}; [2]:{[C]:-1 - require [C]}; [3]:{/usr/share/rspamd/lualib/global_functions.lua:21 - [main]}; [4]:{[C]:-1 - require [C]}; [5]:{rspamd.lua:19 - [main]};

• ERROR: rspamd failed to start
  mail ~ #

Steps to Reproduce

1. Make sure your using Lua 5.1
2. Compile rspamd 3.8.0
3. Start rspamd 3.8.0

Expected behavior
After changing to Lua 5.3 or Lua 5.4 it just starts:
mail ~ # /etc/init.d/rspamd start

• Caching service dependencies ... [ ok ]
  implicitly enabling luapattern returncodes_matcher for rule nil
  implicitly enabling luapattern returncodes_matcher for rule nil
• Starting rspamd ...
  2024-01-20 14:51:04 #7788(main) <12d986>; main; main: rspamd 3.8.0 is loading configuration, build id: release [ ok ]
  mail ~ #

Versions

mail ~ # rspamd --version
Rspamd daemon version 3.8.0

CPU architecture x86_64; features: avx2, avx, sse2, sse3, ssse3, sse4.1, sse4.2, rdrand
Hyperscan enabled: TRUE
Jemalloc enabled: FALSE
LuaJIT enabled: FALSE (Lua version: Lua 5.1)
ASAN enabled: FALSE
BLAS enabled: FALSE
Fasttext enabled: FALSE

Additional Information

https://bugs.gentoo.org/922522

[arkamar]

I have bisected it, the issue was introduced in commit b189c9f ("[Minor] lua_maps docs: apply formatting"). I guess it is about nested comments.