Busted, custom assertions and Undefined field warning

[HiPhish]

Hello everyone,

I have defined custom assertions for busted which I use in my tests to make them more readable:

assert.channel(nvim).at_position(0, 5).for_language('lua').has_extmarks()

The problem is that the language server does not know that assert has the field channel, so I get the warning Undefined field channel. Is there a way to teach the language server about my custom assertions, or at least get it to ignore this particular error for the assert global while still keeping auto-completion?

To make things more complicated in my case, I use busted to test Neovim plugins. For the test to work the test has to be run with Neovim as the Lua interpreter instead of whatever the lua command on my machine is. That means I have between two and three different Neovim processes:

• The one I am using to edit my code
• The one running the busted tests (so I can use Neovim's Lua library)
• Possibly a third one spawned as part of a test to test the behaviour of the plugin

The custom assertions are defined to run inside the second Neovim. If anyone cares about how this tower of madness works, I have written a couple of blog posts:

• Testing Neovim plugins with Busted (the most relevant one)
• Introducing Yo-Dawg.nvim (running Neovim inside Neovim)
• Introducing nvim-busted-shims

[tomlau10]

I assume you're using the busted lua addon, which already adds the following into your .luarc.json:

    "workspace.library": [
        "${addons}/busted/module/library",
        "${3rd}/luassert/library"
    ],

Then I tried to look at how the annotation of assert is provided by this addon, and found that it is using a luassert class for it:

• https://github.com/LuaCATS/busted/blob/5ed85d0e016a5eb5eca097aa52905eedf1b180f1/library/busted.lua#L1-L3
• https://github.com/LuaCATS/luassert/blob/d3528bb679302cbfdedefabb37064515ab95f7b9/library/luassert.lua#L1-L7

Therefore one way to "fix" your warning, is by injecting your channel() definition into the luassert class.

---

You may have another meta file in your project containing the following:

---@meta

---@class luassert.custom
local custom = {}

---@return table
function custom.channel(channel) end

---@class luassert: luassert.custom

• this defines a channel() function for luassert.custom, and then make luassert to extend your custom class 🤔
• you may even further annotate the channel() function, to have it return another class to allow completion for your chain call at_position / for_language and so on.

Hope this helps 🙂

[tomlau10]

In my test above, I used the addon manger from LuaLS to install the library, not by manually git submodule add 😕
The workspace.library is added by the addon manger after installing the library, not me

    "workspace.library": [
        "${addons}/busted/module/library",
        "${3rd}/luassert/library"
    ],

• you can see from the following image, that assert.channel is resolved to my luassert.custom.channel() -> table definition
  

---

And seems the busted library annotation requires luassert as well:
https://github.com/LuaCATS/busted/blob/5ed85d0e016a5eb5eca097aa52905eedf1b180f1/config.json#L4

If you want to manage to library installation on your own, maybe you also have to git submodule add luassert as well? 🤔
https://github.com/LuaCATS/luassert

[HiPhish]

The addon manager is for VSCode only, right? So I need to manage addons and my LuaLS configuration manually. The way I understand it I have to do the following steps:

1. Define the addons directory (workspace.userThirdParty) in my .luarc.json
2. Download the addons to that directory (I use Git submodules)
3. Enable the addons by adding the paths to their library directories to workspace.library

It still does not work. Here is my .luarc.json:

{
	"$schema": "https://raw.githubusercontent.com/LuaLS/vscode-lua/master/setting/schema.json",
	"workspace.ignoreDir": ["test/xdg"],
	"workspace.ignoreSubmodules": false,
	"workspake.userThirdParty": [
		".luals/addons"
	],
	"workspace.library": [
		".luals/addons/busted/library",
		".luals/addons/luassert/library",
		".luals/meta"
	]
}

And here is the structure of the .luals directory:

.luals/
├── addons
│   ├── busted
│   │   ├── config.json
│   │   └── library
│   │       └── busted.lua
│   └── luassert
│       ├── config.json
│       └── library
│           ├── luassert
│           │   ├── array.lua
│           │   ├── match.lua
│           │   ├── mock.lua
│           │   ├── spy.d.lua
│           │   ├── spy.lua
│           │   └── stub.lua
│           └── luassert.lua
└── meta
    └── busted.lua

[HiPhish]

OK, I think I have an idea what the problem might be: If I move all these files to a minimal standalone project it works. It's only inside my Neovim project that LuaLS does not pick up on my settings from .luarc.json. I have the language server set up so it auto-recognizes and configures Neovim projects, and it seems that the settings from .luarc.json are ignored rather than being merged into the editor settings. Could that be possible?

EDIT: Or more likely the settings are merged only at the top level, but array settings like workspace.library are overwritten with the editor settings taking precedence.

[HiPhish]

I think I got it now. In the editor configuration I have set runtime.path to ["lua/?.lua", "lua/?/init.lua"], because in Neovim Lua modules are stored in the lua directory. However, this is not true for the addons and the custom meta file. Adding "?.lua" to the .luarc.json file does the trick.

{
	"$schema": "https://raw.githubusercontent.com/LuaLS/vscode-lua/master/setting/schema.json",
	"runtime.path": ["?.lua"],
	"workspace.ignoreDir": ["test/xdg"],
	"workspace.ignoreSubmodules": false,
	"workspake.userThirdParty": [
		".luals/addons"
	],
	"workspace.library": [
		".luals/addons/busted/library",
		".luals/addons/luassert/library",
		".luals/meta"
	]
}

Finally no more yellow undercurls. Thank you for getting me on the right track.