console.lua: close when pressing enter with input.select

When you select an item, due to the submit handler being called
asynchronously, the default item list is redrawn before the console
closes, which is jarring. Fix this by always closing the console as soon
as enter is pressed, as keeping it open is unlikely to be useful with a
fuzzy selector (unlike with input.get() where it can be used e.g. to
implement a Lua REPL). If desired we can later add a close_on_submit
flag defaulting to true.

Also fix a crash when pressing enter without any match.

DOCS/man/lua.rst

@@ -970,8 +970,9 @@ REPL.
 
     ``submit``
         The callback invoked when the user presses Enter. The first argument is
-        the 1-based index of the selected item. You can close the console from
+        the 1-based index of the selected item. Unlike with ``input.get()``, the
-        within the callback by calling ``input.terminate()``.
+        console is automatically closed on submit without having to call
+        ``input.terminate()``.
 
     Example:
 
@@ -984,7 +985,6 @@ REPL.
                 },
                 submit = function (id)
                     mp.commandv("playlist-play-index", id - 1)
-                    input.terminate()
                 end,
             })
 

player/lua/console.lua

@@ -798,9 +798,15 @@ function handle_enter()
         history_add(line)
     end
 
-    if input_caller then
+    if selectable_items then
+        if #matches > 0 then
             mp.commandv('script-message-to', input_caller, 'input-event', 'submit',
-                    utils.format_json({selectable_items and matches[selected_match].index or line}))
+                        utils.format_json({matches[selected_match].index}))
+        end
+        set_active(false)
+    elseif input_caller then
+        mp.commandv('script-message-to', input_caller, 'input-event', 'submit',
+                    utils.format_json({line}))
     else
         -- match "help [<text>]", return <text> or "", strip all whitespace
         local help = line:match('^%s*help%s+(.-)%s*$') or