nvim: Determine python venv on lsp start

nvim/.config/nvim/lua/plug/_lsp.lua

@@ -52,6 +52,15 @@ lsp.on_attach(function(client, bufnr)
         { buffer = bufnr, desc = 'Type definition' })
 end)
 lsp.nvim_workspace()
+-- ensure python virtualenv is determined automatically on lsp start
+lsp.configure("pyright", {
+    on_attach = function(client, _)
+        local python_path, msg = require('util.pyenv').get_path(client.config
+        .root_dir)
+        vim.notify(string.format('%s\n%s', msg, python_path))
+        client.config.settings.python.pythonPath = python_path
+    end
+})
 lsp.setup_nvim_cmp({
     sources = {
         { name = 'path' }, { name = 'nvim_lsp', keyword_length = 2 },

nvim/.config/nvim/lua/util/pyenv.lua

@@ -0,0 +1,45 @@
+local util = require('lspconfig/util')
+local path = util.path
+local T = {}
+local exepath = vim.fn.exepath
+
+local path_sep = function()
+    local is_win = vim.loop.os_uname().sysname:find('Windows')
+    if is_win then
+        return '\\'
+    else
+        return '/'
+    end
+end
+
+-- from https://github.com/ray-x/navigator.lua/issues/247#issue-1465308677
+T.get_path = function(workspace)
+    -- Use activated virtualenv.
+    if vim.env.VIRTUAL_ENV then
+        return path.join(vim.env.VIRTUAL_ENV, 'bin', 'python'), 'virtual env'
+    end
+
+    -- Find and use virtualenv in workspace directory.
+    for _, pattern in ipairs({ '*', '.*' }) do
+        local match = vim.fn.glob(path.join(workspace, pattern, 'pyvenv.cfg'))
+        local sep = path_sep()
+        local py = 'bin' .. sep .. 'python'
+        if match ~= '' then
+            match = string.gsub(match, 'pyvenv.cfg', py)
+            return match, string.format('venv base folder: %s', match)
+        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'),
+                string.format('venv base folder: %s', venv_base_folder)
+        end
+    end
+
+    -- Fallback to system Python.
+    return exepath('python3') or exepath('python') or 'python',
+        'fallback to system python path'
+end
+
+return T