mp.input: avoid displaying outdated completions from the same client

Previously, completion responses from the same client would be displayed
even if the user had since changed the input, as long as a newer
complete event had already been sent. This meant that, if clients took a
sufficiently long time to return completions, then
console.lua would display completions for previous versions of the line
which were no longer valid.

This commit has the client send back the version of the line their
completions apply to, ensuring that `console.lua` displays the
correct completions.

player/javascript/defaults.js

@@ -678,6 +678,7 @@ function register_event_handler(t) {
                 mp.commandv("script-message-to", "console", "complete", JSON.stringify({
                                 client_name: mp.script_name,
                                 handler_id: handler_id,
+                                original_line: args[0],
                                 list: completions,
                                 start_pos: completion_pos,
                                 append: completion_append || "",

player/lua/console.lua

@@ -102,8 +102,6 @@ local completion_buffer = {}
 local selected_completion_index
 local completion_pos
 local completion_append
-local completion_old_line
-local completion_old_cursor
 local autoselect_completion
 local has_completions
 
@@ -1480,8 +1478,6 @@ end
 
 -- Show autocompletions.
 complete = function ()
-    completion_old_line = line
-    completion_old_cursor = cursor
     mp.commandv("script-message-to", input_caller, input_caller_handler,
                 "complete", utils.format_json({line:sub(1, cursor - 1)}))
     render()
@@ -1802,7 +1798,7 @@ mp.register_script_message("complete", function (message)
     message = utils.parse_json(message)
 
     if message.client_name ~= input_caller or message.handler_id ~= input_caller_handler
-       or line ~= completion_old_line or cursor ~= completion_old_cursor then
+       or line:sub(1, cursor - 1) ~= message.original_line then
         return
     end
 

player/lua/input.lua

@@ -60,6 +60,7 @@ local function register_event_handler(t)
                 mp.commandv("script-message-to", "console", "complete", utils.format_json({
                                 client_name = mp.get_script_name(),
                                 handler_id = handler_id,
+                                original_line = args[1],
                                 list = completions,
                                 start_pos = completion_pos,
                                 append = completion_append or "",