Can't set Tile.objectGroup back to null

[juanitogan]

Describe the bug

I can't find a way to remove an ObjectGroup from a Tile. That is, to set Tile.objectGroup back to null after setting it. Either I'm just not finding it, or a method or something is missing.

The best I can currently do is either loop through and remove all objects from the group, or assign it a new empty group.

To Reproduce

tile.objectGroup = new ObjectGroup()
tile.objectGroup = null

Expected behavior

The ObjectGroup associated with the tile in case collision shapes were defined. Returns null if no collision shapes were defined for this tile.

If it can be null (which it can), I should be able to set it back to null, either directly or via method.

Specifications:

• OS: Windows 10
• Tiled Version: 1.9.2

[bjorn]

Yeah, I think there is no reason for this early null check:

tiled/src/tiled/editabletile.cpp

Lines 172 to 177 in 4ae6efd

	void EditableTile::setObjectGroup(EditableObjectGroup *editableObjectGroup)
	{
	if (!editableObjectGroup) {
	ScriptManager::instance().throwNullArgError(0);
	return;
	}

It can be done later where necessary such that we set the tile's object group to null, which is already supported as per this code:

tiled/src/tiled/tilecollisiondock.cpp

Lines 470 to 476 in 4ae6efd

	std::unique_ptr<ObjectGroup> clonedGroup;
	if (!objectGroup->isEmpty())
	clonedGroup.reset(objectGroup->clone());
	QUndoStack *undoStack = mTilesetDocument->undoStack();
	mApplyingChanges = true;
	undoStack->push(new ChangeTileObjectGroup(mTilesetDocument, mTile, std::move(clonedGroup)));