Use ssh:// protocol to install - http "The unauthenticated git protocol on port 9418 is no longer supported."
Installation works by changing the protocol to SSH
$ sudo luarocks install --server=ssh://luarocks.org/dev lua-lsp # works
Installation fails with HTTP URL which is currently suggested in lua-lsp README
$ sudo luarocks install --server=http://luarocks.org/dev lua-lsp # fails
...
fatal: remote error:
The unauthenticated git protocol on port 9418 is no longer supported.
Please see https://github.blog/2021-09-01-improving-git-protocol-security-github/ for more information.
This change will be made permanent 2022-04-16. We're currently on brownout period, so the old command will work intermittently.
I'm not familiar with luarocks, simply providing the command that worked for me on Debian 11-Bullseye. I noticed the error while writing installation instructions for Micro editor's new LSP Plugin. It seems that Lua-lsp works to some extent with this Micro's LSP plugin, supporting linting (in the left side gutter) and alt-D jump to definition inside the same file.
This doesnt work, and i get the following error: Warning: Failed searching manifest: Unsupported protocol ssh Installing https://luarocks.org/lua-lsp-0.1.0-2.src.rock
Error: Failed finding Lua header files. You may need to install them or configure LUA_INCDIR.