According, to the commit log, this was converted to Lua 5.4 with rev. 937fa4ad3d90e5083a8fbe72042d48aafa7591ae in July 2020, but the present version (3.7.0, which is the latest from upstream) doesn't appear to work with Lua 5.4.3. Whatever package I try to install globally or locally, I'm getting the following backtrace:

Error: LuaRocks 3.7.0 bug (please report at https://github.com/luarocks/luarocks/issues).
Arch.: linux-x86_64
/usr/share/lua/5.4/ssl/https.lua:66: bad argument #2 to 'method' (string expected, got light userdata)
stack traceback:
[C]: in function 'socket.http.request'
/usr/share/lua/5.4/ssl/https.lua:132: in function 'ssl.https.request'
/usr/share/lua/5.4/luarocks/fs/lua.lua:729: in upvalue 'request'
/usr/share/lua/5.4/luarocks/fs/lua.lua:837: in upvalue 'http_request'
/usr/share/lua/5.4/luarocks/fs/lua.lua:904: in function 'luarocks.fs.lua.download'
(...tail calls...)
/usr/share/lua/5.4/luarocks/fetch.lua:154: in function 'luarocks.fetch.fetch_url'
/usr/share/lua/5.4/luarocks/fetch.lua:50: in function 'luarocks.fetch.fetch_caching'
/usr/share/lua/5.4/luarocks/manif.lua:108: in function 'luarocks.manif.load_manifest'
/usr/share/lua/5.4/luarocks/search.lua:111: in function </usr/share/lua/5.4/luarocks/search.lua:101>
(...tail calls...)
/usr/share/lua/5.4/luarocks/search.lua:155: in function 'luarocks.search.search_repos'
/usr/share/lua/5.4/luarocks/search.lua:241: in function 'luarocks.search.find_suitable_rock'
/usr/share/lua/5.4/luarocks/search.lua:263: in function 'luarocks.search.find_rock_checking_lua_versions'
/usr/share/lua/5.4/luarocks/cmd/install.lua:242: in function 'luarocks.cmd.install.command'
(...tail calls...)
[C]: in function 'xpcall'
/usr/share/lua/5.4/luarocks/cmd.lua:663: in function 'luarocks.cmd.run_command'
/usr/bin/luarocks:38: in main chunk
[C]: in ?

If I change the shebang in /usr/bin/luarocks to `#!/usr/bin/lua5.3` then the program works just fine, so assuming that the package worked after switching to Lua 5.4, I guess that there's a new incompatibility with Lua 5.4.3. Has anyone checked that?

This is just a heads up, the bug is probably upstream, not in the packaging. I've reported it here: https://github.com/luarocks/luarocks/issues/1309