From 91bd0c7e985c6d5f98fddd22dccb6a4d30cae86f Mon Sep 17 00:00:00 2001 From: thetaepsilon-gamedev Date: Fri, 22 Dec 2017 17:57:00 +0000 Subject: [PATCH] teleport_tube.lua: add checks for hash collisions in positions table --- teleport_tube.lua | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/teleport_tube.lua b/teleport_tube.lua index 9a66de2..d707717 100644 --- a/teleport_tube.lua +++ b/teleport_tube.lua @@ -50,6 +50,11 @@ local function read_tube_db() return tp_tube_db end +-- debug formatter for coordinates used below +local fmt = function(pos) + return pos.x..", "..pos.y..", "..pos.z +end + -- updates or adds a tube local function set_tube(pos, channel, can_receive) local tubes = tp_tube_db or read_tube_db() @@ -63,6 +68,19 @@ local function set_tube(pos, channel, can_receive) end -- we haven't found any tp tube to update, so lets add it + -- but sanity check that the hash has not already been inserted. + -- if so, complain very loudly and refuse the update so the player knows something is amiss. + -- to catch regressions of https://github.com/minetest-mods/pipeworks/issues/166 + local existing = tp_tube_db[hash] + if existing ~= nil then + local e = "error" + minetest.log(e, "pipeworks teleport tube update refused due to position hash collision") + minetest.log(e, "collided hash: "..hash) + minetest.log(e, "tried-to-place tube: "..fmt(pos)) + minetest.log(e, "existing tube: "..fmt(existing)) + return + end + tp_tube_db[hash] = {x=pos.x,y=pos.y,z=pos.z,channel=channel,cr=can_receive} save_tube_db() end