Solved [0.4 LUA] Obsidian knife (Attempt to index field ? a nil value)

[elnelson]

Hello, otlanders. I rework this script to make it more RPGish but i found a strange error when someone tries to skin something that is not in the table i made.Tried to patch it with some conditions but seems i failed tho.
The console spams an error (see attached image):



Here is the script

local MINOTAUR_LEATHER, LIZARD_LEATHER, GREEN_DRAGON_LEATHER, RED_DRAGON_LEATHER, HARDENED_BONE, BEHEMOTH_FANG = 5878, 5876, 5877, 5948, 5925, 5893

local config = {
    [3086] = {25, 5897, skill = 10}, --wolfpaw
    [2969] = {25, 5897, skill = 25}, --wolfpaw
    [3109] = {25, 5896, skill = 25}, --bearpaw
    [2935] = {25, 10610, skill = 0}, --pig foot
    [4265] = {25, 5890, skill = 0}, --chicken feather
    [3090] = {25, MINOTAUR_LEATHER, skill = 20},
    [2871] = {25, MINOTAUR_LEATHER, skill = 30},
    [2866] = {25, MINOTAUR_LEATHER, skill = 40},
    [2876] = {25, MINOTAUR_LEATHER, skill = 50},
    [4298] = {25, 5894, skill = 10}, --batwing
    [3104] = {25, GREEN_DRAGON_LEATHER, skill = 100},
    [2881] = {25, RED_DRAGON_LEATHER, skill = 250},
    [2931] = {25, BEHEMOTH_FANG, skill = 300},
    [4256] = {25, LIZARD_LEATHER, skill = 50},
    [4259] = {25, LIZARD_LEATHER, skill = 50},
    [4262] = {25, LIZARD_LEATHER, skill = 50},
    [11285] = {25, LIZARD_LEATHER, skill = 50},
    [11277] = {25, LIZARD_LEATHER, skill = 50},
    [11269] = {25, LIZARD_LEATHER, skill = 50},
    [11273] = {25, LIZARD_LEATHER, skill = 50},
    [11281] = {25, LIZARD_LEATHER, skill = 50},
    [6303] = {25, 2231, skill = 100},
    [3031] = {25, HARDENED_BONE, skill = 150},
    [2817] = {25, 10611, skill = 0}, --snakeskin
    [3067] = {25, 10606, skill = 5}, --troll hair
    [2897] = {25, 10568, skill = 0} --troll hair

}
 
local pumpkin_items = {
    [1] = {2683},
    [2] = {2688, 50},
    [3] = {6571},
    [4] = {6492},
    [5] = {6574},
    [6] = {6526},
    [7] = {2096},
    [8] = {9005, 20}
}
 
local sculpting = {
    [7441] = {randsize = 4, newid = 7442},
    [7442] = {randsize = 5, newid = 7444},
    [7444] = {randsize = 6, newid = 7445},
    [7445] = {randsize = 7, newid = 7446},
}
 
function onUse(cid, item, fromPosition, itemEx, toPosition)
    if itemEx.itemid == 8961 then
        if getPlayerStorageValue(cid, 81279) <= 0 then
            doCreatureSay(cid, "Happy Halloween!", TALKTYPE_ORANGE_1)
            doSendMagicEffect(getCreaturePosition(cid), math.random(28,30))
            setPlayerStorageValue(cid, 81279, 1)
            local v = pumpkin_items[math.random(#pumpkin_items)]
            doPlayerAddItem(cid, v[1], v[2] or 1)
        else
            doCreatureSay(cid, "You already used your knife on the corpse.", TALKTYPE_ORANGE_1, false, cid)
        end
        return true
    end
 
    -- Sculpting
    local v = sculpting[itemEx.itemid]
    if v then
        if(math.random(v.randsize) == 1) then
            doTransformItem(itemEx.uid, v.newid)
        else
            doRemoveItem(itemEx.uid)
            doCreatureSay(cid, "The attempt at sculpting failed miserably.", TALKTYPE_ORANGE_1)
        end
        doSendMagicEffect(toPosition, CONST_ME_HITAREA)
        return true
    end
 
    -- summons
local professionSkill = getPlayerStorageValue(cid, 1035) 
 if itemEx.actionid == 91347 then
return doPlayerSendCancel(cid, "You cant skin a summon corpse.")
end
    local skin = config[itemEx.itemid]
    
    if not(isInArray({2897, 3067, 2806,3086, 2969, 3109, 2935, 4265, 3090, 2871, 2866, 2786, 4298, 3104, 2881, 2931, 4256,4259,4262,11285,11277,11269,11273,11281,6303,3031,2817}, itemEx.itemid)) then
        doSendMagicEffect(getPlayerPosition(cid), CONST_ME_POFF)
        doCreatureSay(cid, "You cant skin this!", TALKTYPE_ORANGE_1)
        return false
    end
     local reqskill = config[itemEx.itemid].skill
    if isInArray({3067}, itemEx.itemid) and professionSkill >= reqskill then
        local chance = (math.random (1,math.ceil(professionSkill/200)))
        doPlayerAddItem(cid, 10606, chance)
        doSendMagicEffect(toPosition, CONST_ME_MAGIC_GREEN)
        doTransformItem(itemEx.uid, 2806)
    end
   
    if professionSkill < reqskill and isInArray({2897, 3067, 3086, 2969, 3109, 2935, 4265, 3090, 2871, 2866, 2786, 4298, 3104, 2881, 2931, 4256,4259,4262,11285,11277,11269,11273,11281,6303,3031,2817}, itemEx.itemid) then
    doSendMagicEffect(getPlayerPosition(cid), CONST_ME_POFF)
    doCreatureSay(cid, "You have to be at least skill ".. config[itemEx.itemid].skill  .." in tanning to do that!", TALKTYPE_ORANGE_1)
    return false
    end

    
    -- Skinning
    v = config[itemEx.itemid]
    if not v then
        return false
    elseif math.random(100) <= v[1]+professionSkill/20 then

    local chance = (math.random (1,math.ceil(professionSkill/200)))
        doPlayerAddItem(cid, v[2], chance)
        doSendMagicEffect(toPosition, CONST_ME_MAGIC_GREEN)
    else
        doSendMagicEffect(toPosition, CONST_ME_BLOCKHIT)
    end
    if math.random(1, professionSkill*1.15) >= professionSkill then
        if professionSkill < 500 then
            setPlayerStorageValue(cid, 1035, professionSkill + 1)
            doPlayerSendTextMessage(cid, MESSAGE_EVENT_ADVANCE, "You advanced in tanning ["..professionSkill.."].")
        end
        end
    if not isInArray({3067}, itemEx.itemid) then
    doTransformItem(itemEx.uid, itemEx.itemid + 1)
    
    doDecayItem(itemEx.uid)
end
    return true
end

 

[Don Daniello]

Line 90 is the problem:

local reqskill = config[itemEx.itemid].skill

You have to check if config has that itemid key before accessing its value:

local reqskill = 0
if isInArray(config, itemEx.itemid) then
    reqskill = config[itemEx.itemid].skill
end

 

[elnelson]

Line 90 is the problem:

local reqskill = config[itemEx.itemid].skill

You have to check if config has that itemid key before accessing its value:

local reqskill = 0
if isInArray(config, itemEx.itemid) then
    reqskill = config[itemEx.itemid].skill
end

may i ask why you use this line?

local reqskill = 0

i have seen it in many scripts but i dont really understand the value of 0 in this case

BTW. thank you very much sir, take your like

 

[Ochman]

He's simple setting it's the initial value of variable reqskill.

This way, if he's trying to attempt variable's value that didn't pass this part:

if isInArray(config, itemEx.itemid) then
    reqskill = config[itemEx.itemid].skill
end

he would use it's 0 value (instead of nil value, which is similar to what generates your error code but with different variable).

 

[Don Daniello]

i have seen it in many scripts but i dont really understand the value of 0 in this case

0 in this case is a value used when "if" does not hold, like @ochmar explained. That is the case for all items that are NOT in the config.

 

[elnelson]

nice, thank you very much! now i will practice that new technique