Add dap_enrich_config to pass enrich_config to dap adapter config

[gcollura]

DAP suggests passing an enrich_config function to the adapter configuration to allow "hydrating" the launch.json configuration in case it contains an envFile, eg. mfussenegger/nvim-dap#548 (comment)

It can also be useful to expose this function given that dap.adapters.go gets overwritten by go.nvim. https://github.com/mfussenegger/nvim-dap/blob/8517126e9323e346f6a99b3b594c5a940b914dcd/doc/dap.txt#L199-L220

If nil, the enrich_config function is ignored, so we're going to default to that: https://github.com/mfussenegger/nvim-dap/blob/8517126e9323e346f6a99b3b594c5a940b914dcd/lua/dap.lua#L458

The motivation for me is that calling GoEnv depending on which launch configuration I select is a bit cumbersome, especially when different configurations specify different envFiles.

[ray-x]

Thanks! Looks good to me.

[gcollura]

Thanks for merging my PRs!

For reference this is how I implemented envFile with this new feature:

	{
		"ray-x/go.nvim",
		event = { "CmdlineEnter" },
		ft = { "go", "gomod" },
		dependencies = {
			"ray-x/guihua.lua",
			"neovim/nvim-lspconfig",
			"nvim-treesitter/nvim-treesitter",
			"mfussenegger/nvim-dap",
		},
		build = ':lua require("go.install").update_all_sync()',
		opts = {
			dap_enrich_config = require("dap.enrich_config").enrich_config,
		}
	}

in ~/.config/nvim/lua/dap/enrich_config.lua:

local M = {}

local var_placeholders = {
	["${file}"] = function(_)
		return vim.fn.expand("%:p")
	end,
	["${fileBasename}"] = function(_)
		return vim.fn.expand("%:t")
	end,
	["${fileBasenameNoExtension}"] = function(_)
		return vim.fn.fnamemodify(vim.fn.expand("%:t"), ":r")
	end,
	["${fileDirname}"] = function(_)
		return vim.fn.expand("%:p:h")
	end,
	["${fileExtname}"] = function(_)
		return vim.fn.expand("%:e")
	end,
	["${relativeFile}"] = function(_)
		return vim.fn.expand("%:.")
	end,
	["${relativeFileDirname}"] = function(_)
		return vim.fn.fnamemodify(vim.fn.expand("%:.:h"), ":r")
	end,
	["${workspaceFolder}"] = function(_)
		return vim.fn.getcwd()
	end,
	["${workspaceFolderBasename}"] = function(_)
		return vim.fn.fnamemodify(vim.fn.getcwd(), ":t")
	end,
	["${env:([%w_]+)}"] = function(match)
		return os.getenv(match) or ""
	end,
}

function M.enrich_config(config, on_config)
	local final_config = vim.deepcopy(config)

	if final_config.envFile then
		local filePath = final_config.envFile
		for key, fn in pairs(var_placeholders) do
			filePath = filePath:gsub(key, fn)
		end

		for line in io.lines(filePath) do
			local words = {}
			for word in string.gmatch(line, "[^=]+") do
				table.insert(words, word)
			end
			if not final_config.env then
				final_config.env = {}
			end
			final_config.env[words[1]] = words[2]
		end
	end

	on_config(final_config)
end

return M

Credits to @niklod for the code for enrich_config