From bbde06c72e5d783b02646ba8d4b15e4402310d3d Mon Sep 17 00:00:00 2001
From: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>
Date: Fri, 22 Jun 2018 21:23:12 +0100
Subject: [PATCH] [floodfill] Bugfix: Don't get caught in an infinite loop if
 the search & replace nodes are identical

Also fix a crash in the //floodfill command logic if pos1 is nil
---
 worldeditadditions/floodfill.lua     |  4 ++++
 worldeditadditions_commands/init.lua | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/worldeditadditions/floodfill.lua b/worldeditadditions/floodfill.lua
index 168f50f..608decf 100644
--- a/worldeditadditions/floodfill.lua
+++ b/worldeditadditions/floodfill.lua
@@ -62,6 +62,10 @@ function worldedit.floodfill(start_pos, radius, replace_node)
 	local replace_id = minetest.get_content_id(replace_node)
 	local radius_sq = radius*radius
 	
+	if search_id == replace_id then
+		return false
+	end
+	
 	local count = 0
 	local remaining_nodes = Queue.new()
 	Queue.enqueue(remaining_nodes, start_pos_index)
diff --git a/worldeditadditions_commands/init.lua b/worldeditadditions_commands/init.lua
index e46f6ba..1f50a97 100644
--- a/worldeditadditions_commands/init.lua
+++ b/worldeditadditions_commands/init.lua
@@ -43,14 +43,28 @@ minetest.register_chatcommand("/floodfill", {
 			return false
 		end
 		
+		if not worldedit.pos1[name] then
+			worldedit.player_notify(name, "Error: No pos1 defined.")
+			return false
+		end
+		
 		local start_time = os.clock()
 		local nodes_replaced = worldedit.floodfill(worldedit.pos1[name], radius, replace_node)
 		local time_taken = os.clock() - start_time
 		
+		if nodes_replaced == false then
+			worldedit.player_notify(name, "Error: The search node is the same as the replace node.")
+			return false
+		end
+		
 		worldedit.player_notify(name, nodes_replaced .. " nodes replaced in " .. time_taken .. "s")
 		minetest.log("action", name .. " used //floodfill at " .. worldeditadditions.vector.tostring(worldedit.pos1[name]) .. ", replacing " .. nodes_replaced .. " nodes in " .. time_taken .. "s")
 	end, function(name, params_text)
 		local replace_node, radius = parse_params_floodfill(params_text)
+		
+		if not worldedit.pos1[name] then
+			return 0 -- The actual command will send the error message to the client
+		end
 		-- Volume of a hemisphere
 		return math.ceil(((4 * math.pi * (tonumber(radius) ^ 3)) / 3) / 2)
 	end)