feat: ensure strict ordering of feedkeys initiated by luasnip.

This allows us to first of all, be certain that successive ls.jump()
always end up at the correct position, but also enables running all
these feedkeys with "ni", which means that they will be executed at the
correct time even if the typeahead contains other keys! This makes
luasnip behave deterministically in macros, which was certainly not the
case before!

We can also finally remove all the ugly vim.wait(...)-calls from the
tests :D (at least those related to waiting on luasnip-actions to
complete, we still need some related to filesystem-events.)
Now, these only have to happen for actions that are not hooked into the
feedkeys-action-queue, like `ls.expand`. IMO while not perfect, this is
a great improvement because `ls.expand` are rarely called back-to-back,
while `ls.jump` are.

A last neat addition is that autosnippets can be expanded properly when
replaying a macro by inserting expand_auto before other typeahead, thus
making it take place at the correct position.

lua/luasnip/config.lua

@@ -121,13 +121,7 @@ c = {
 		end)
 		if session.config.enable_autosnippets then
 			ls_autocmd("InsertCharPre", function()
-				Luasnip_just_inserted = true
-			end)
-			ls_autocmd({ "TextChangedI", "TextChangedP" }, function()
-				if Luasnip_just_inserted then
-					require("luasnip").expand_auto()
-					Luasnip_just_inserted = nil
-				end
+				require("luasnip.util.feedkeys").feedkeys_insert("<cmd>lua require('luasnip').expand_auto()<cr>")
 			end)
 		end
 

lua/luasnip/nodes/insertNode.lua

@@ -6,6 +6,7 @@ local node_util = require("luasnip.nodes.util")
 local types = require("luasnip.util.types")
 local events = require("luasnip.util.events")
 local extend_decorator = require("luasnip.util.extend_decorator")
+local feedkeys = require("luasnip.util.feedkeys")
 
 local function I(pos, static_text, opts)
 	static_text = util.to_string_table(static_text)
@@ -49,16 +50,7 @@ function ExitNode:input_enter(no_move, dry_run)
 		self.parent:subtree_set_pos_rgrav(begin_pos, 1, true)
 
 		if not no_move then
-			if vim.fn.mode() == "i" then
-				util.insert_move_on(begin_pos)
-			else
-				vim.api.nvim_feedkeys(
-					vim.api.nvim_replace_termcodes("<Esc>", true, false, true),
-					"n",
-					true
-				)
-				util.normal_move_on_insert(begin_pos)
-			end
+			feedkeys.insert_at(begin_pos)
 		end
 
 		self:event(events.enter)
@@ -122,20 +114,9 @@ function InsertNode:input_enter(no_move, dry_run)
 		-- SELECT snippet text only when there is text to select (more oft than not there isnt).
 		local mark_begin_pos, mark_end_pos = self.mark:pos_begin_end_raw()
 		if not util.pos_equal(mark_begin_pos, mark_end_pos) then
-			util.any_select(mark_begin_pos, mark_end_pos)
+			feedkeys.select_range(mark_begin_pos, mark_end_pos)
 		else
-			-- if current and target mode is INSERT, there's no reason to leave it.
-			if vim.fn.mode() == "i" then
-				util.insert_move_on(mark_begin_pos)
-			else
-				-- mode might be VISUAL or something else, but <Esc> always leads to normal.
-				vim.api.nvim_feedkeys(
-					vim.api.nvim_replace_termcodes("<Esc>", true, false, true),
-					"n",
-					true
-				)
-				util.normal_move_on_insert(mark_begin_pos)
-			end
+			feedkeys.insert_at(mark_begin_pos)
 		end
 	end
 

lua/luasnip/nodes/textNode.lua

@@ -3,6 +3,7 @@ local util = require("luasnip.util.util")
 local types = require("luasnip.util.types")
 local events = require("luasnip.util.events")
 local extend_decorator = require("luasnip.util.extend_decorator")
+local feedkeys = require("luasnip.util.feedkeys")
 
 local TextNode = node_mod.Node:new()
 
@@ -25,16 +26,7 @@ function TextNode:input_enter(no_move, dry_run)
 
 	if not no_move then
 		local mark_begin_pos = self.mark:pos_begin_raw()
-		if vim.fn.mode() == "i" then
-			util.insert_move_on(mark_begin_pos)
-		else
-			vim.api.nvim_feedkeys(
-				vim.api.nvim_replace_termcodes("<Esc>", true, false, true),
-				"n",
-				true
-			)
-			util.normal_move_on_insert(mark_begin_pos)
-		end
+		feedkeys.insert_at(mark_begin_pos)
 	end
 
 	self:event(events.enter, no_move)

lua/luasnip/nodes/util.lua

@@ -3,6 +3,7 @@ local ext_util = require("luasnip.util.ext_opts")
 local types = require("luasnip.util.types")
 local key_indexer = require("luasnip.nodes.key_indexer")
 local session = require("luasnip.session")
+local feedkeys = require("luasnip.util.feedkeys")
 
 local function subsnip_init_children(parent, children)
 	for _, child in ipairs(children) do
@@ -125,7 +126,7 @@ end
 
 local function select_node(node)
 	local node_begin, node_end = node.mark:pos_begin_end_raw()
-	util.any_select(node_begin, node_end)
+	feedkeys.select_range(node_begin, node_end)
 end
 
 local function print_dict(dict)

lua/luasnip/util/feedkeys.lua

@@ -0,0 +1,141 @@
+-- insert operations into typeahead buffer in a controlled manner.
+-- We want to follow these guidelines:
+-- * maintain order of luasnip-operations. Example:
+--   `ls.jump() ls.jump()`, the first jump is completely executed, and only
+--   then the second jump is.
+-- * insert our operations before other typeahead.
+--   This is to behave correctly in a macro: IIUC the complete macro is written
+--   into typeahead, so if our operations are appended, we will jump way later
+--   than in the actual recorded "session", and input won't end up where it
+--   belongs.
+--
+-- We will achieve these goals by only ever having one operation in the
+-- typeahead, and once it is finished it calls a callback that will insert any
+-- other keys that were requested to be executed.
+--
+-- This scheme is inspired by @hrsh7th's work in nvim-cmp.
+local util = require("luasnip.util.util")
+
+local M = {}
+
+local current_id = 0
+local executing_id = nil
+
+-- contains functions which take exactly one argument, the id.
+local enqueued_actions = {}
+
+local function _feedkeys_insert(id, keys)
+	executing_id = id
+	vim.api.nvim_feedkeys(
+		vim.api.nvim_replace_termcodes(keys .. "<cmd>lua require('luasnip.util.feedkeys').confirm(" .. id .. ")<cr>", true, false, true),
+		-- folds are opened manually now, no need to pass t.
+		-- n prevents langmap from interfering.
+		"ni",
+		true
+	)
+end
+
+local function enqueue_action(fn)
+	-- get unique id and increment global.
+	local keys_id = current_id
+	current_id = current_id + 1
+
+	-- if there is nothing from luasnip currently executing, we may just insert
+	-- into the typeahead
+	if executing_id == nil then
+		fn(keys_id)
+	else
+		enqueued_actions[keys_id] = fn
+	end
+end
+
+function M.feedkeys_insert(keys)
+	enqueue_action(function(id)
+		_feedkeys_insert(id, keys)
+	end)
+end
+
+-- pos: (0,0)-indexed.
+local function cursor_set_keys(pos, before)
+	if before then
+		if pos[2] == 0 then
+			pos[1] = pos[1] - 1
+			-- pos2 is set to last columnt of previous line.
+			-- # counts bytes, but win_set_cursor expects bytes, so all's good.
+			pos[2] =
+				#vim.api.nvim_buf_get_lines(0, pos[1], pos[1] + 1, false)[1]
+		else
+			pos[2] = pos[2] - 1
+		end
+	end
+
+	return "<cmd>lua vim.api.nvim_win_set_cursor(0,{"
+		-- +1, win_set_cursor starts at 1.
+		.. pos[1] + 1
+		.. ","
+		-- -1 works for multibyte because of rounding, apparently.
+		.. pos[2]
+		.. "})"
+		.. "<cr><cmd>:silent! foldopen!<cr>"
+end
+
+function M.select_range(b, e)
+	enqueue_action(function(id)
+		-- stylua: ignore
+		_feedkeys_insert(id,
+			-- this esc -> movement sometimes leads to a slight flicker
+			-- TODO: look into preventing that reliably.
+			-- Go into visual, then place endpoints.
+			-- This is to allow us to place the cursor on the \n of a line.
+			-- see #1158
+			"<esc>"
+			-- open folds that contain this selection.
+			-- we assume that the selection is contained in at most one fold, and
+			-- that that fold covers b.
+			-- if we open the fold while visual is active, the selection will be
+			-- wrong, so this is necessary before we enter VISUAL.
+			.. cursor_set_keys(b)
+			-- start visual highlight and move to b again.
+			-- since we are now in visual, this might actually move the cursor.
+			.. "v"
+			.. cursor_set_keys(b)
+			-- swap to other end of selection, and move it to e.
+			.. "o"
+			.. (vim.o.selection == "exclusive" and
+				cursor_set_keys(e) or
+				-- set before
+				cursor_set_keys(e, true))
+			.. "o<C-G><C-r>_" )
+	end)
+end
+
+-- move the cursor to a position and enter insert-mode (or stay in it).
+function M.insert_at(pos)
+	enqueue_action(function(id)
+		-- if current and target mode is INSERT, there's no reason to leave it.
+		if vim.fn.mode() == "i" then
+			-- can skip feedkeys here, we can complete this command from lua.
+			-- Just have to make sure to call confirm afterward, since there
+			-- may be more actions enqueued.
+			-- We don't have to set the executing_id, since there's no way
+			-- enqueue_action could be called before `confirm`.
+			util.set_cursor_0ind(pos)
+			vim.api.nvim_command("redraw!")
+			M.confirm(id)
+		else
+			-- mode might be VISUAL or something else => <Esc> to know we're in NORMAL.
+			_feedkeys_insert(id, "<Esc>i" .. cursor_set_keys(pos))
+		end
+	end)
+end
+
+function M.confirm(id)
+	executing_id = nil
+
+	if enqueued_actions[id+1] then
+		enqueued_actions[id+1](id+1)
+		enqueued_actions[id+1] = nil
+	end
+end
+
+return M

lua/luasnip/util/util.lua

@@ -125,84 +125,6 @@ local function bytecol_to_utfcol(pos)
 	return { pos[1], vim.str_utfindex(line[1] or "", pos[2]) }
 end
 
-local function replace_feedkeys(keys, opts)
-	vim.api.nvim_feedkeys(
-		vim.api.nvim_replace_termcodes(keys, true, false, true),
-		-- folds are opened manually now, no need to pass t.
-		-- n prevents langmap from interfering.
-		opts or "n",
-		true
-	)
-end
-
--- pos: (0,0)-indexed.
-local function cursor_set_keys(pos, before)
-	if before then
-		if pos[2] == 0 then
-			pos[1] = pos[1] - 1
-			-- pos2 is set to last columnt of previous line.
-			-- # counts bytes, but win_set_cursor expects bytes, so all's good.
-			pos[2] =
-				#vim.api.nvim_buf_get_lines(0, pos[1], pos[1] + 1, false)[1]
-		else
-			pos[2] = pos[2] - 1
-		end
-	end
-
-	return "<cmd>lua vim.api.nvim_win_set_cursor(0,{"
-		-- +1, win_set_cursor starts at 1.
-		.. pos[1] + 1
-		.. ","
-		-- -1 works for multibyte because of rounding, apparently.
-		.. pos[2]
-		.. "})"
-		.. "<cr><cmd>:silent! foldopen!<cr>"
-end
-
--- any for any mode.
--- other functions prefixed with eg. normal have to be in that mode, the
--- initial esc removes that need.
-local function any_select(b, e)
-	-- stylua: ignore
-	replace_feedkeys(
-		-- this esc -> movement sometimes leads to a slight flicker
-		-- TODO: look into preventing that reliably.
-		-- Go into visual, then place endpoints.
-		-- This is to allow us to place the cursor on the \n of a line.
-		-- see #1158
-		"<esc>"
-		-- open folds that contain this selection.
-		-- we assume that the selection is contained in at most one fold, and
-		-- that that fold covers b.
-		-- if we open the fold while visual is active, the selection will be
-		-- wrong, so this is necessary before we enter VISUAL.
-		.. cursor_set_keys(b)
-		-- start visual highlight and move to b again.
-		-- since we are now in visual, this might actually move the cursor.
-		.. "v"
-		.. cursor_set_keys(b)
-		-- swap to other end of selection, and move it to e.
-		.. "o"
-		.. (vim.o.selection == "exclusive" and
-			cursor_set_keys(e) or
-			-- set before
-			cursor_set_keys(e, true))
-		.. "o<C-G><C-r>_" )
-end
-
-local function normal_move_on_insert(new_cur_pos)
-	-- moving in normal and going into insert is kind of annoying, eg. when the
-	-- cursor is, in normal, on a tab, i will set it on the beginning of the
-	-- tab. There's more problems, but this is very safe.
-	replace_feedkeys("i" .. cursor_set_keys(new_cur_pos))
-end
-
-local function insert_move_on(new_cur_pos)
-	-- maybe feedkeys this too.
-	set_cursor_0ind(new_cur_pos)
-	vim.api.nvim_command("redraw!")
-end
-
 local function multiline_equal(t1, t2)
 	for i, line in ipairs(t1) do
 		if line ~= t2[i] then
@@ -479,9 +401,6 @@ return {
 	get_cursor_0ind = get_cursor_0ind,
 	set_cursor_0ind = set_cursor_0ind,
 	move_to_mark = move_to_mark,
-	normal_move_on_insert = normal_move_on_insert,
-	insert_move_on = insert_move_on,
-	any_select = any_select,
 	remove_n_before_cur = remove_n_before_cur,
 	get_current_line_to_cursor = get_current_line_to_cursor,
 	line_chars_before = line_chars_before,

tests/integration/choice_spec.lua

@@ -98,9 +98,7 @@ describe("ChoiceNode", function()
 		-- change text in insertNode.
 		feed("c")
 		exec_lua("ls.jump(1)")
-		exec_lua("vim.wait(10, function() end)")
 		exec_lua("ls.change_choice(1)")
-		exec_lua("vim.wait(10, function() end)")
 		screen:expect({
 			grid = [[
 			c ^b                                               |
@@ -118,9 +116,7 @@ describe("ChoiceNode", function()
 
 		-- change choice on outer choiceNode.
 		exec_lua("ls.jump(-1)")
-		exec_lua("vim.wait(10, function() end)")
 		exec_lua("ls.change_choice(1)")
-		exec_lua("vim.wait(10, function() end)")
 		screen:expect({
 			grid = [[
 			^b                                                 |

tests/integration/jump_spec.lua

@@ -139,7 +139,6 @@ describe("Jumping", function()
 
 		-- jump into restoreNode in first choice.
 		exec_lua("ls.jump(1)")
-		exec_lua("vim.wait(10, function() end)")
 		exec_lua("ls.change_choice(1)")
 		screen:expect({
 			grid = [[