The recommended luarocks invocation completely breaks SILE (on macOS?)

[davidchisnall]

If you use a package that does not exist, SILE tells you to first do:

      luarocks --lua-version 5.1 --tree lua_modules install {package}

This installs the package under lua_modules. So far so good.

It then tells you to:

      eval $(luarocks --lua-version 5.1 --tree lua_modules path)

This then sets LUA_PATH and LUA_CPATH, which overrides SILE's built-in paths and prevents it from finding things (the first error is for penlight, but then all of the other things SILE depends on).

It looks as if SILE forcibly preserves some paths. The error list includes things like:

	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/lua-libraries/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/lua-libraries/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/lua_modules/share/lua/5.1/sile/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/lua_modules/share/lua/5.1/sile/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/lua_modules/share/lua/5.1/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/lib/sile/lua_modules/share/lua/5.1/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/lua-libraries/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/lua-libraries/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/lua_modules/share/lua/5.1/sile/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/lua_modules/share/lua/5.1/sile/pl/import_into/init.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/lua_modules/share/lua/5.1/pl/import_into.lua'
	no file '/opt/homebrew/Cellar/sile/0.15.9/share/sile/lua_modules/share/lua/5.1/pl/import_into/init.lua'

But the SILE dependencies are installed under /opt/homebrew/Cellar/sile/0.15.9/libexec, so this doesn't work.

You can work around this by doing:

export LUA_PATH="${LUA_PATH};;"
export LUA_CPATH="${LUA_CPATH};;" 

This (from reading the comments in the SILE code) makes add (prepend) the environment variables to the default path, rather than replacing.

[alerque]

If you are installing Rocks to a project-local lua_modules tree, you shouldn't need that eval $(luarocks path) business at all, that one tree location is built in already.

That's not to say there isn't a real issue here, just a tip to maybe get you back to work fast while I try to make out what's up with the rest of this.

[davidchisnall]

Ah, I had a stale invocation left over in that terminal. Okay, simply not running the second command seems to work well.

[Omikhleia]

Reading the exchanges, I've added the "question" label, but honestly

• Is there an issue? It's not clear.
• Is there something actually being worked upon?

Please clarify the expectations ;)

[davidchisnall]

Ideally, SILE would not tell you to run a command that breaks SILE if you run it. Especially when you get the correct behaviour by simply not running the command.

[alerque]

@davidchisnall That's kind of obvious. What isn't obvious is that the command is needed in some circumstances and we are not able to detect whether it will or won't be needed, so we just suggest it it all cases. What really needed fixing is that the command should either ⓐ fix the problem if necessary or ⓑ be a no-op for situations that didn't need the fix. It should not have broken anything in the first place, and that was an issue with Homebrew packaging. I'm addressing this from that end so that the fix either works or is a noop.

[davidchisnall]

If I understood the rest of the thread:

• If you follow the first command correctly, it installs things in the lua_rocks subdirectory of the current directory.
• By default, SILE looks there for packages.
• The second command is never needed if the first command was followed verbatim.
• The second command is not correct if the first command was not followed verbatim because it replaces, rather than augmenting, the directories where SILE looks for Lua packages.