nvim: Split python venv fetching into multiple

Now we can either fetch the python venv basefolder
(`require('core.util').get_python_venv_basefolder()`) or specifically
the python binary contained within (`.get_python_bin()`).

Additionally, the venv result should be cached for the duration of using
nvim so that we only have to fetch it once, regardless of how many
modules require it.

nvim/.config/nvim/lua/core/util.lua

@@ -32,28 +32,42 @@ end
 local function path_join(...)
 	return table.concat(vim.tbl_flatten({ ... }), "/")
 end
+function T.get_python_venv_bin(workspace)
+	local pyenv = T.get_python_venv_basefolder(workspace)
+	if not pyenv then
+		-- Fallback to system Python.
+		return vim.fn.exepath("python3") or vim.fn.exepath("python") or "python"
+	end
+	return path_join(pyenv, "bin", "python")
+end
+-- cache path so we can call it multiple times
+local venv_path = ""
 -- return the current python environment path
-function T.get_python_venv(workspace)
+function T.get_python_venv_basefolder(workspace)
+	if venv_path and venv_path ~= "" then
+		return venv_path
+	end
+
 	-- Use activated virtualenv.
 	if vim.env.VIRTUAL_ENV then
-		return path_join(vim.env.VIRTUAL_ENV, "bin", "python")
+		venv_path = vim.env.VIRTUAL_ENV
+		return venv_path
 	end
 	-- Find and use virtualenv in workspace directory.
 	for _, pattern in ipairs({ "*", ".*" }) do
 		local match = vim.fn.glob(path_join(workspace, pattern, "pyvenv.cfg"))
 		if match ~= "" then
-			local py = path_join("bin", "python")
-			match = string.gsub(match, "pyvenv.cfg", py)
-			return match
+			match = string.gsub(match, "pyvenv.cfg", "")
+			venv_path = match
+			return venv_path
 		end
 		match = vim.fn.glob(path_join(workspace, pattern, "poetry.lock"))
 		if match ~= "" then
 			local venv_base_folder = vim.fn.trim(vim.fn.system("poetry env info -p"))
-			return path_join(venv_base_folder, "bin", "python")
+			venv_path = venv_base_folder
+			return venv_path
 		end
 	end
-	-- Fallback to system Python.
-	return vim.fn.exepath("python3") or vim.fn.exepath("python") or "python"
 end
 
 return T

nvim/.config/nvim/lua/plugins/config/lsp.lua

@@ -167,7 +167,7 @@ local python_path
 lspconfig.basedpyright.setup({
 	on_attach = function(client, bufnr)
 		if python_path == nil then
-			python_path, _ = require("core.util").get_python_venv(client.config.root_dir)
+			python_path, _ = vim.fn.expand(require("core.util").get_python_venv_bin(client.config.root_dir))
 		end
 		-- print(string.format("[PYTHON VENV]: %s", vim.inspect(python_path)))
 		client.config.settings.python = {} or client.config.settings.python
@@ -179,7 +179,7 @@ lspconfig.ruff_lsp.setup({
 	on_attach = function(client, bufnr)
 		on_attach(client, bufnr)
 		if python_path == nil then
-			python_path, _ = require("core.util").get_python_venv(client.config.root_dir)
+			python_path, _ = vim.fn.expand(require("core.util").get_python_venv_bin(client.config.root_dir))
 		end
 		client.config.settings.python = {} or client.config.settings.python
 		client.config.settings.python.pythonPath = python_path