Flame sound plays when restoring music puzzle progress

[wjt]

Threadbare version

v0.2.1

Affected scene

res://scenes/quests/lore_quests/quest_001/1_music_puzzle/music_puzzle.tscn

Description

Steps to reproduce:

1. Start the game from the title screen (so that state is persisted!)
2. In the settings, mute music (optional but makes the bug clearer)
3. Enter the Musician's quest
4. Solve 1 or more steps of the puzzle
5. Pause -> Abandon Quest (or exit to title)
6. Return to the quest

Expected result:

The signs that you had previously solved remain solved, but no "fire-lighting" whoosh sound is played at the start of the level

Actual result:

The "whoosh" sound is played.

[wjt]

There is code in sequence_puzzle_hint_sign.gd that tries to avoid this (penultimate line, with comment):

func update_solved_state() -> void:
	var was_node_ready: bool = is_node_ready()
	if not was_node_ready:
		await ready
	animated_sprite.play(&"solved" if is_solved else &"idle")
	interact_area.disabled = not (
		demonstrate_sequence.has_connections() and (is_solved or interactive_hint)
	)
	## We don't want to play the fire start sound if the bonfire started on.
	solved_player.playing = is_solved and was_node_ready
	solved_ambient_player.playing = is_solved

But this depends on is_solved being set prior to the sign becoming ready.

The code that restores the state runs when the root node becomes ready - and all child nodes become ready before their parent, so that's too late.

I looked at moving the state load/save into sequence_puzzle.gd itself (which might be a good idea anyway - it's just a couple of lines but we'll end up duplicating it many times otherwise) but that doesn't really help because the SequencePuzzle discovers its signs (which must be its descendants) on _ready which again is after each sign has become ready.

Maybe we need set_solved(is_solved: bool, silent: bool = false).