From 93be162fd7a880918090f973031c1165349988c7 Mon Sep 17 00:00:00 2001
From: norrbotten <axelsp@gmail.com>
Date: Mon, 19 Aug 2019 12:22:54 +0200
Subject: [PATCH 1/2] fix infinite recursion when you link gearboxes in a loop

---
 lua/entities/acf_gearbox.lua | 47 +++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/lua/entities/acf_gearbox.lua b/lua/entities/acf_gearbox.lua
index 6c2496e3d..5db5f88d3 100644
--- a/lua/entities/acf_gearbox.lua
+++ b/lua/entities/acf_gearbox.lua
@@ -937,6 +937,43 @@ function ENT:ChangeDrive(value)
 	
 end
 
+-- Searches the "tree" which gearbox-gearbox connections forms, if the source is found
+-- anywhere in the targets link tree, this function will return true and the loop path
+function ACF_SearchGearboxLinkTree(source, target)
+	local queue = { target }
+	local parent = { }
+
+	-- search the link tree
+	while #queue > 0 do
+		local ent = table.remove(queue)
+
+		if ent == source then
+			-- backtrack the loop
+			local nextInLoop = source:EntIndex()
+			local loop = { }
+
+			while nextInLoop do
+				table.insert(loop, nextInLoop)
+				nextInLoop = parent[nextInLoop]
+			end
+
+			loop = table.Reverse(loop)
+
+			return true, loop
+		end
+		
+		if not ent.WheelLink then continue end
+		
+		-- add each link to the queue
+		for k, v in ipairs(ent.WheelLink) do
+			table.insert(queue, v.Ent)
+			parent[v.Ent:EntIndex()] = ent:EntIndex()
+		end
+	end
+
+	return false
+end
+
 function ENT:Link( Target )
 
 	if not IsValid( Target ) or not table.HasValue( { "prop_physics", "acf_gearbox", "tire" }, Target:GetClass() ) then
@@ -949,7 +986,15 @@ function ENT:Link( Target )
 			return false, "That is already linked to this gearbox!"
 		end
 	end
-	
+
+	local hasLoop, loop = ACF_SearchGearboxLinkTree(self, Target)
+	if hasLoop then
+		local loopStr = string.format("%s (%i) (target) loops back to %s (%i) (source)",
+			ents.GetByIndex(loop[1]):GetClass(), loop[1], ents.GetByIndex(loop[#loop]):GetClass(), loop[#loop])
+		
+		return false, "You cannot link gearboxes in a loop!\n" .. loopStr
+	end
+
 	-- make sure the angle is not excessive
 	local InPos = Vector( 0, 0, 0 )
 	if Target.IsGeartrain then

From 3c77dc40745e2f09ffb7a7b93d941ba53a3a35e3 Mon Sep 17 00:00:00 2001
From: norrbotten <axelsp@gmail.com>
Date: Mon, 19 Aug 2019 12:49:24 +0200
Subject: [PATCH 2/2] source/target print was kinda unnecessary

---
 lua/entities/acf_gearbox.lua | 29 ++++++-----------------------
 1 file changed, 6 insertions(+), 23 deletions(-)

diff --git a/lua/entities/acf_gearbox.lua b/lua/entities/acf_gearbox.lua
index 5db5f88d3..7e3b6f8b2 100644
--- a/lua/entities/acf_gearbox.lua
+++ b/lua/entities/acf_gearbox.lua
@@ -938,36 +938,23 @@ function ENT:ChangeDrive(value)
 end
 
 -- Searches the "tree" which gearbox-gearbox connections forms, if the source is found
--- anywhere in the targets link tree, this function will return true and the loop path
+-- anywhere in the targets link tree, this function will return true
 function ACF_SearchGearboxLinkTree(source, target)
 	local queue = { target }
-	local parent = { }
-
+	
 	-- search the link tree
 	while #queue > 0 do
 		local ent = table.remove(queue)
 
 		if ent == source then
-			-- backtrack the loop
-			local nextInLoop = source:EntIndex()
-			local loop = { }
-
-			while nextInLoop do
-				table.insert(loop, nextInLoop)
-				nextInLoop = parent[nextInLoop]
-			end
-
-			loop = table.Reverse(loop)
-
-			return true, loop
+			return true
 		end
 		
 		if not ent.WheelLink then continue end
-		
+
 		-- add each link to the queue
 		for k, v in ipairs(ent.WheelLink) do
 			table.insert(queue, v.Ent)
-			parent[v.Ent:EntIndex()] = ent:EntIndex()
 		end
 	end
 
@@ -987,12 +974,8 @@ function ENT:Link( Target )
 		end
 	end
 
-	local hasLoop, loop = ACF_SearchGearboxLinkTree(self, Target)
-	if hasLoop then
-		local loopStr = string.format("%s (%i) (target) loops back to %s (%i) (source)",
-			ents.GetByIndex(loop[1]):GetClass(), loop[1], ents.GetByIndex(loop[#loop]):GetClass(), loop[#loop])
-		
-		return false, "You cannot link gearboxes in a loop!\n" .. loopStr
+	if ACF_SearchGearboxLinkTree(self, Target) then
+		return false, "You cannot link gearboxes in a loop!"
 	end
 
 	-- make sure the angle is not excessive