invalidate_diarch_grand_wedding_effect

invalidate_diarch_grand_wedding_effect = {
	# Invalidate grand weddings
	diarch ?= {
		if = {
			limit = {
				# scope:diarch is currently an active Diarch
				exists = liege
				is_diarch = yes
				liege = {
					diarch = scope:diarch
					has_active_diarchy = yes
				}
				# scope:diarch was promised a Grand Wedding
				has_variable = promised_grand_wedding_by
			}
			betrothed ?= { save_scope_as = betrothed } # A promised wedding can outlive the betrothal
			# Save scopes of spouses, and organizers from variables
			scope:diarch = {
				add_to_list = informee
				var:promised_grand_wedding_by ?= {
					add_to_list = informee
					var:promised_grand_wedding_to ?= { add_to_list = informee }
				}
			}
			scope:betrothed ?= {
				add_to_list = informee
				var:promised_grand_wedding_by ?= {
					add_to_list = informee
					var:promised_grand_wedding_to ?= { add_to_list = informee }
				}
			}
			var:promised_grand_wedding_by = {
				clean_grand_wedding_betrothal_variables = yes
			}
			# Clean up variables and inform relevant characters of invalidation
			every_in_list = {
				list = informee
				send_interface_message = {
					type = msg_betrothal_invalidated
					title = grand_wedding_cancelled_by_regency_title
					left_icon = scope:diarch
					right_icon = scope:betrothed
					custom_tooltip = grand_wedding_cancelled_by_regency_desc
				}
			}
		}
	}
}

As written in game/common/scripted_effects/00_diarchy_scripted_effects.txt.