java ArrayIndexOutOfBoundsException w/o recursions or infinite loops

I'm trying to create an automatic strip mining turtle that returns to home when it runs out of fuel.
It determines how many strips to make and for what length each via tArgs

As soon as I run the program with any arguments, it gives me the java.lang.ArrayIndexOutOfBoundsException error. To the best of my knowledge, this is commonly caused by recursive functions that call upon itself or incorrectly utilized infinite loops. However my program does not use either of these so I am left scratching my head.

The code can be located here: http://pastebin.com/N5TQnAsh

Here is a screenshot of the error itself in minecraft:


Any other suggestions to my code would be cool as well

The problem is in your goTo function, as it calls itself.

function goTo(x,z)
    local distanceToTarget = xPos-x+zPos-z

    if canRTH() and distanceToTarget+2<turtle.getFuelLevel() then
        if z>zPos then
            faceForward()
            for i=1,z-zPos do
                if turtle.detect() then
                    turtle.dig()
                end
                moveForward()
                if turtle.detectUp() then
                    turtle.digUp()
                end
                turtle.suck()
                zPos=zPos+1
                print("forwards1")
            end

        end

        if z<zPos then
            faceBackward()

            for i=1,zPos-z do
                if turtle.detect() then
                    turtle.dig()
                end
                moveForward()
                if turtle.detectUp() then
                    turtle.digUp()
                end
                turtle.suck()
                zPos=zPos-1
                print("backwards1")
            end

        end

        if x>xPos then
            faceRight()

            for i=1,x-xPos do
                if turtle.detect() then
                    turtle.dig()
                end
                moveForward()
                if turtle.detectUp() then
                    turtle.digUp()
                end
                turtle.suck()
                xPos=xPos+1
                print("right1")
            end

        end

        if x<xPos then
            faceLeft()

            for i=1,xPos-x do
                if turtle.detect() then
                    turtle.dig()
                end
                    moveForward()
                if turtle.detectUp() then
                    turtle.digUp()
                end
                turtle.suck()
                xPos=xPos-1
                print("left1")
            end

        end
    else
        local lastX,lastZ=xPos,zPos
        returnToHome() --# << returnToHome calls goTo, RECURSIVE FUNCTION CALL
        print("I need fuel in slot 1, then press enter")
        io.read()
        turtle.select(1)
        turtle.refuel()
        print("Resuming..")
        goTo(lastX,lastZ) --# <<<< RECURSIVE FUNCTION CALL
    end
end

In fact, what I think happens is the turtle has no fuel, so the goTo function calls returnToHome, which calls goTo, which (since you still have no fuel) calls returnToHome… etc.

Thank you very much, I didn't catch that!
I made a boolean for it to be able to tell if it needs to returnToHome so that way the goTo function doesn't force itself to returnToHome when called by the returnToHome function…if that makes sense

Here are the updated parts:

local tArgs = {...}

if #tArgs ~= 2 then
    print("Usage: strip <# of strips> <strip depth>")
    return
end

local stripCount=tonumber(tArgs[1])
local stripDepth=tonumber(tArgs[2])
local heading="forward"
local xPos,zPos=0,0
local returningToHome=false -- added a boolean to keep it from asking for more fuel while returning home
...
function returnToHome()
returningToHome=true --new line
    goTo(0,zPos)
    goTo(0,0)
    faceLeft()
    for i=1,16 do
	    turtle.select(i)
	    turtle.drop()
    end
    turtle.select(1)
    faceForward()
returningToHome=false --new line
end

It now works exactly as intended, thank you for the help!