Plugin breaks with function in table

[TabulateJarl8]

Hey! I started using your plugin today and it works great, however I believe I've discovered a bug. I'm not sure if this is something you're actually able to fix on your side, but here's an example snipped from my configuration for conform which triggers the error:

local prettier = function(bufnr)
	if require("conform").get_formatter_info("prettier", bufnr).available then
		return { "prettier" }
	else
		return {}
	end
end

require("conform").setup({
	formatters_by_ft = {
		javascript = prettier,
		typescript = prettier,
		vue = prettier,
	},
})

It throws this error on startup:

Error detected while processing BufEnter Autocommands for "*":
Error executing vim.schedule lua callback: ...ed/mason-conform.nvim/lua/mason-conform/auto_install.lua:10: bad argument #1 to 'pairs' (table expected, got function)
stack traceback:
        [C]: in function 'pairs'
        ...ed/mason-conform.nvim/lua/mason-conform/auto_install.lua:10: in function ''
        vim/_editor.lua: in function <vim/_editor.lua:0>
        [C]: in function 'wait'
        ...oload/plugged/nvim-tree.lua/lua/nvim-tree/git/runner.lua:171: in function '_wait'
        ...oload/plugged/nvim-tree.lua/lua/nvim-tree/git/runner.lua:221: in function 'run'
        ...utoload/plugged/nvim-tree.lua/lua/nvim-tree/git/init.lua:243: in function 'load_project_status'
        ...ad/plugged/nvim-tree.lua/lua/nvim-tree/explorer/init.lua:49: in function '_load'
        ...ad/plugged/nvim-tree.lua/lua/nvim-tree/explorer/init.lua:41: in function 'new'
        ...im/autoload/plugged/nvim-tree.lua/lua/nvim-tree/core.lua:20: in function 'init'
        .../nvim-tree.lua/lua/nvim-tree/actions/root/change-dir.lua:88: in function 'f'
        .../nvim-tree.lua/lua/nvim-tree/actions/root/change-dir.lua:77: in function 'force_dirchange'
        ...ig/nvim/autoload/plugged/nvim-tree.lua/lua/nvim-tree.lua:117: in function <...ig/nvim/autoload/plugged/nvim-tree.lua/lua/nvim-tree.lua:105>

If i replace the function in the table with just {"prettier"} the issue goes away. Also, if I call the function like prettier() instead of just putting the function object in the table, I believe the issue also goes away. Now that I'm using this plugin, I don't really need to worry about needing this specific function, but it may come up in the future for others so I figured I'd document it here at least. Thanks for your work, and let me know if you need any more info

[zapling]

Thanks for the report 😄

I'm not sure if this is something you're actually able to fix on your side

I did not know that you could provide a function to conform in this manner.

Now that I'm using this plugin, I don't really need to worry about needing this specific function

Yea that is my take on this issue as well. Configuring a function like this with conform does not really make sense in the context of this plugin, at least not to me.

I'd say this is very low on my priority list right now.

[marty-oehme]

I have stumbled upon this as well when selecting one of multiple formatters, followed by running more formatters.

With the release of 7.0.0, conform.nvim switched to a new configuration format which deprecates the nested table configuration style for running one formatter out of a pool and subsequently another formatter:

require("conform").setup({
	formatters_by_ft = {
		markdown = { { "prettier", "prettierd" }, "cbfmt" },
	},
})

This produces a warning with the new version.
The manual instead recommends the following code recipe:

---@param bufnr integer
---@param ... string
---@return string
local function first(bufnr, ...)
	local conform = require("conform")
	for i = 1, select("#", ...) do
		local formatter = select(i, ...)
		if conform.get_formatter_info(formatter, bufnr).available then
			return formatter
		end
	end
	return select(1, ...)
end

require("conform").setup({
	formatters_by_ft = {
		markdown = function(bufnr)
			return { first(bufnr, "prettierd", "prettier"), "cbfmt" }
		end,
	},
})

This seems to pose the same issue again.

I agree that it's not a priority issue but with the documentation recommending this way of configuration I think more reports are going to appear which stumble upon the same error.

[zapling]

With the release of 7.0.0, conform.nvim switched to a new configuration format

Thanks for the heads up, we should definitely support this going forward then.

[lukoshkin]

One way to fix this is to make amends to both the plugins conform.nvim and mason-conform.nvim

• In conform.nvim:

  ---@param bufnr integer | nil
  ---@param ... string
  ---@return string | table
  local function first(bufnr, ...)
    if bufnr == nil then
      return { ... }
    end
  
    for i = 1, select("#", ...) do
      local formatter = select(i, ...)
      if conform.get_formatter_info(formatter, bufnr).available then
        return formatter
      end
    end
    return select(1, ...)
  end

  Suppose you have somewhere in settings:

      json = function(bufnr)
        return { first(bufnr, "prettierd", "prettier"), "fixjson" }
      end,

• In mason-conform.nvim in lua/mason-conform/auto_install.lua, adjust auto_install function:

  local function auto_install()
    local config = require("mason-conform").config
    local formatters_by_ft = require("conform").formatters_by_ft
  
    local formatters_to_install = {}
    for _, formatters in pairs(formatters_by_ft) do
  +    if type(formatters) == "function" then
  +      formatters = formatters(nil)
  +    end
      for _, formatter in pairs(formatters) do
        -- Support case where the user has defined multiple formatters
        -- for said filetype. E.g javascript = { { "prettierd", "prettier" } }
        if type(formatter) == "table" then
          for _, f in pairs(formatter) do
            formatters_to_install[f] = 1
          end
        else
          formatters_to_install[formatter] = 1
        end
      end
    end
  
    -- Filter out formatters that the user wants to ignore
    for _, formatter_to_ignore in pairs(config.ignore_install) do
      formatters_to_install[formatter_to_ignore] = nil
    end
  
    for conformFormatter, _ in pairs(formatters_to_install) do
      local package = mapping.conform_to_package[conformFormatter]
      if package ~= nil then
        require("mason-conform.install").try_install(package)
      end
    end
  end

[lukoshkin]

@zapling, maybe we can allow passing functions in the formatters_by_ft section? At least in a way, it is demonstrated above, and document it in the README for the rest of folks?

[zapling]

The recipe from mason-conform to Run the first available formatter followed by more formatters posses a problem for this plugin.

We need to get all possible formatters at run-time, in order for us to download them via mason. Adding a function to the return list (in this case first(bufnr)) makes it so we do not get all the formatters, and are therefor unable to download them all.

We could support a function, but we probably do not have a bufnr that we can pass in, so the users first(bufnr) function needs to handle that, maybe returning the full list if nil?

Is that a solution that could work?