Bug: /triggers debug view doesn't show if a CPos trigger gets removed

[Leo512bit]

Issue Summary

/triggers debug view doesn't show if a CPos trigger gets removed

Reproduction

Have a script where a CPos trigger gets added then removed.

Expected behavior

The overlay should be removed once a CPos trigger gets removed.

Tested on:playtest-20221203

[anvilvapre]

Related source lines. It would suggest that trigger positions in actor map are not updated.

OpenRA/OpenRA.Mods.Common/Traits/World/CellTriggerOverlay.cs

Lines 68 to 87 in c82be17

	IEnumerable<IRenderable> IRenderAnnotations.RenderAnnotations(Actor self, WorldRenderer wr)
	{
	if (!enabled)
	yield break;
	var triggerPositions = wr.World.ActorMap.TriggerPositions().ToHashSet();
	foreach (var uv in wr.Viewport.VisibleCellsInsideBounds.CandidateMapCoords)
	{
	if (self.World.ShroudObscures(uv))
	continue;
	var cell = uv.ToCPos(wr.World.Map);
	if (!triggerPositions.Contains(cell))
	continue;
	var center = wr.World.Map.CenterOfCell(cell);
	yield return new TextAnnotationRenderable(font, center, 1024, color, "T");
	}
	}

In ActorMap the cell triggers are maintained by key in a hash map. The entries are removed but the key is not removed from the cellTriggerInfluence dictionary.

OpenRA/OpenRA.Mods.Common/Traits/World/ActorMap.cs

Lines 540 to 552 in c82be17

	public void RemoveCellTrigger(int id)
	{
	if (!cellTriggers.TryGetValue(id, out var trigger))
	return;
	foreach (var c in trigger.Footprint)
	{
	if (!cellTriggerInfluence.ContainsKey(c))
	continue;
	cellTriggerInfluence[c].RemoveAll(t => t == trigger);
	}
	}

One fix would be for the overlay to check if the position keys actually contain any cell triggers. I.e. if the dictionary value has any CellTriggers left in the list.

A better fix may be to remove the key from the cellTriggerInfluence dictionary in ActorMap.RemoveCellTrigger when the last Trigger is removed from the list.

Please propose the best solution.