feat: add fennel-ls

[XeroOl]

Adds fennel-ls language server

[williamboman]

Thanks!

[XeroOl]

Oh no! I think luarocks needs to be version 3.10+ to be able to install the fennel-ls rock anywhere other than system-wide, due to a bug in luarocks.

[williamboman]

Oh no! I think luarocks needs to be version 3.10+ to be able to install the fennel-ls rock anywhere other than system-wide, due to a bug in luarocks.

Ah that's a bit unfortunate. Luarocks packages are currently only tested on macOS, which only recently updated to 3.10+. I've re-ran the test so hopefully it'll pass now.

[williamboman]

Ok had to jump through some hoops to add Luarocks support on all platforms on GitHub runners. For some reason the build passes on Windows but fails on Darwin (macOS) and Linux with similar errors (using Luarocks v3.11.0):

sh: src/fennel-ls/message.lua: No such file or directory

Error: Build error: fennel failed to compile the file src/fennel-ls/message.fnl

sh: 1: cannot create src/fennel-ls/handlers.lua: Directory nonexistent

Error: Build error: fennel failed to compile the file src/fennel-ls/handlers.fnl

The command used by mason.nvim to invoke Luarocks is:

luarocks install --tree <install_path> fennel-ls 0.1.2-2

[XeroOl]

That's a strange error! I will look into it and let you know when I fix it.

[williamboman]

That's a strange error! I will look into it and let you know when I fix it.

I wasn't able to reproduce when using Luarocks installed via Homebrew. However, I was able to by replicating the installation process of the GitHub actions (basically downloading the Luarocks and Lua source tarballs, unpacking them, and compiling Luarocks against the compiled Lua artifact). Makes me wonder if there's an issue with Luarocks itself, I'll try to investigate further as well.

[williamboman]

So CI is failing on darwin_x64 even with Luarocks 3.11 installed via Homebrew. I really can't tell where the issue is, but the fact that it keeps failing when using different methods of Luarocks installation is a bit concering. Let's get this merged anyway, I'll disable CI explicitly.

[XeroOl]

The issue was with the luarocks package luarocks-build-fennel, which fennel-ls depends on. @tranzystorekk was kind enough to make a patch that seems to fix the issue, and I've pushed it live to luarocks.

The CI can be enabled now.