nvim: Do not establish quarto molten session on open

We now disable the automatic establishing of quarto molten sessions
(using the virtual environment provided python interpreter) as soon as
the file is opened since it can have some negative side-effects and also
slows down quarto file opening.
Instead, use the `JupyterStart` command to establish a jupyter session
in the correct environment and initialize a molten session.

The behaviour can be re-enabled with
`vim.g.quarto_auto_init_molten_session = true`.

nvim/.config/nvim/after/ftplugin/quarto.lua

@@ -1,3 +1,4 @@
+
 local default_buffer_session = function()
 	local buffer_path = vim.api.nvim_buf_get_name(0) or vim.fn.tempname()
 	local temp_path = vim.fn.stdpath("run") .. "/molten-sessions" .. buffer_path .. ".json"
@@ -15,7 +16,7 @@ local startsession = function(file, args)
 
 	local path = require("core.util").get_python_venv_bin()
 	if not path then
-	    return
+		return
 	end
 	vim.g["python3_host_prog"] = path
 
@@ -44,15 +45,18 @@ vim.api.nvim_create_user_command("JupyterStart", function()
 	startsession(vim.b["sessionfile"] or default_buffer_session())
 end, {})
 
-vim.api.nvim_create_autocmd({"InsertEnter", "BufEnter"}, {
+if vim.g.quarto_auto_init_molten_session then
-	callback = function()
+	vim.api.nvim_create_autocmd({ "InsertEnter", "BufEnter" }, {
-		if vim.b["sessionfile"] == nil then
+		callback = function()
-			local path = default_buffer_session()
+			if vim.b["sessionfile"] == nil then
-			vim.b["sessionfile"] = path
+				local path = default_buffer_session()
-			vim.schedule_wrap(startsession(path))
+				vim.b["sessionfile"] = path
-		end
+				vim.schedule_wrap(startsession(path))
-	end,
+			end
-})
+		end,
+	})
+end
+
 -- -- -- TODO find better way to enable lsp key mappings for quarto buffers
 -- -- local prefix = require("which-key").register
 -- -- prefix({ ["<localleader>l"] = { name = "+lsp" } })

nvim/.config/nvim/lua/core/settings.lua

@@ -1,3 +1,9 @@
+-- Change (personal) plugin options
+--  mainly intended for things I have not packaged as plugin but may
+--  require options to be set.
+vim.g.quarto_auto_init_molten_session = false
+
+-- Change (Neo)Vim default options
 local default_builtins_disabled = { "netrw", "netrwPlugin" }
 local disable_builtins = function(builtins)
 	for _, plugin in pairs(builtins) do