From 3a859a941dd87e3338342c38f899b1f5119bd298 Mon Sep 17 00:00:00 2001
From: Wyrrrd <wyrrrd@gmx.de>
Date: Mon, 24 Feb 2020 18:56:01 +0100
Subject: [PATCH] Added check for empty filter and whitelist mode

Avoids overwriting filter on replacing preexisting inserters/ghosts
---
 changelog.txt |  1 +
 control.lua   | 35 +++++++++++++++++++++++------------
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/changelog.txt b/changelog.txt
index 538c5d1..15f4db6 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -3,6 +3,7 @@ Version: 0.18.5
 Date: 24. 2. 2020
   Changes:
     - Added hidden dependency to Bob's Adjustable Inserters (fixes setting filter from wrong inventory when pickup location is rotated)
+	- Added check for empty filter and whitelist mode to avoid overwriting filter on replacing preexisting inserters/ghosts
 
   Locale:
     - Added translated mod description
diff --git a/control.lua b/control.lua
index aff2c44..c3544ef 100644
--- a/control.lua
+++ b/control.lua
@@ -1,6 +1,15 @@
 --control.lua
 
 --functions definitions
+local function is_filter_empty(inserter)
+	for slot = 1,inserter.filter_slot_count do
+		if inserter.get_filter(slot) then
+			return false
+		end
+		return true
+	end
+end
+
 local function get_items_by_content(inserter,inventory)
 	local items = {}
 	for item,_ in pairs(inventory.get_contents()) do
@@ -25,18 +34,20 @@ local function on_built_entity(event)
 	local inserter = event.created_entity
 	if inserter.type == "inserter" then
 		if inserter.filter_slot_count then
-			local pickup = inserter.surface.find_entities_filtered({position = inserter.pickup_position, limit = 1})
-			if #pickup > 0 then
-				local inventory = pickup[1].get_output_inventory()
-				if inventory then
-					local mode = game.players[event.player_index].mod_settings["Autofilter_Mode"].value
-					if mode == "content" and not inventory.is_empty() then
-						for slot,item in pairs(get_items_by_content(inserter,inventory)) do
-							inserter.set_filter(slot,item)
-						end
-					elseif mode == "filter" and inventory.is_filtered() then
-						for slot,item in pairs(get_items_by_filter(inserter,inventory)) do
-							inserter.set_filter(slot,item)
+			if is_filter_empty(inserter) and inserter.inserter_filter_mode == "whitelist" then
+				local pickup = inserter.surface.find_entities_filtered({position = inserter.pickup_position, limit = 1})
+				if #pickup > 0 then
+					local inventory = pickup[1].get_output_inventory()
+					if inventory then
+						local mode = game.players[event.player_index].mod_settings["Autofilter_Mode"].value
+						if mode == "content" and not inventory.is_empty() then
+							for slot,item in pairs(get_items_by_content(inserter,inventory)) do
+								inserter.set_filter(slot,item)
+							end
+						elseif mode == "filter" and inventory.is_filtered() then
+							for slot,item in pairs(get_items_by_filter(inserter,inventory)) do
+								inserter.set_filter(slot,item)
+							end
 						end
 					end
 				end