Unknown error in python
<p>I am getting a strange incorrect indentation error that I cannot track down. As far as I know, I did not modify this file since last time it was correctly working.</p>

<p>Edit: Ok it turns out I did modify it unknowingly (obviously something had to have changed since last time). I hit a hotkey in my editor which had turned some tabs into spaces. Thanks!</p>

<p>The error is on line 100: ctrl f for "###"</p>

<pre><code>#!/usr/bin/env python
import sys
from collections import deque #high performance queue "deck"

class Node(object):
        def __init__(self,x,y,history):
                self.locationx = x
                self.locationy = y
                self.data = None
                self.history = history #previous node to go backwards

def printNodePathTrace(inNode,width,height,mapTerrain,frontier):
    #travel backward through node history until history == None is reached
    #print off map of path
    mapPath = mapTerrain
    for i in range(width): #fill map with blanks
        for j in range(height):
            mapPath[i][j] = '-'

    #print frontier list
    print "length of frontier"
    print len(frontier)
    for item in frontier:

        #print item.locationy
        #print item.locationx
        mapPath[item.locationy][item.locationx] = '*'

    #print path found
    done = 0
    count = 0
    currentNode = inNode
    while(done == 0 and count &lt; 50):
        mapPath[currentNode.locationy][currentNode.locationx] = '#'
        if currentNode.history == None:
            done = 1
        currentNode = currentNode.history
        count += 1
    printMap(mapPath)

def printMap(mapTerrain): #horizontal right positive x, verticle down positive y
        for i in mapTerrain:
            for j in i:
                sys.stdout.write(j)
            sys.stdout.write('\n')

def printMapStartAndGoal(mapTerrain,startX,startY,goalX,goalY):
    #Y is row, X is column. Y is vertical, X is horizontal
    temp1 = mapTerrain[startY][startX]
    temp2 = mapTerrain[goalY][goalX]
    mapTerrain[startY][startX] = 'S'
    mapTerrain[goalY][goalX] = 'G'
    printMap(mapTerrain)
    mapTerrain[startY][startX] = temp1
    mapTerrain[goalY][goalX] = temp2

def main():
    #Input map
    #Your program should be able to read a map file in the following format.
    #Width Height
    #StartX StartY
    #GoalX GoalY
    #map
    searchMode = "BFS" #options are BFS, LC, ID, A*1, A*2

    logfile = open("smallmap2.txt", "r")
    [width,height] = map(int,logfile.readline().split())
    [startX,startY] = map(int,logfile.readline().split())
    [goalX,goalY] = map(int,logfile.readline().split())

    mapTerrainInput = logfile.read()
    mapTerrain = map(list,mapTerrainInput.splitlines())
    #map the list function to mapTerrainInput split into lines without '\n'

    printMapStartAndGoal(mapTerrain,startX,startY,goalX,goalY)

    print mapTerrain
    printMap(mapTerrain)

    closedList = [] #contains list of nodes visited already
    frontier = deque([])
    startNode = Node(startX,startY,None)

    #check if node is a goal node
    #add node to closed list
    #add expansions to frontier list (not ones on closed list)
    #Repeat with next node in Frontier

    goalFound = 0 ### there's an error with this line's indentation???
    iterationCount = 0
    currentNode = startNode
    while goalFound == 0 and iterationCount &lt; 500: #stop when goal is found
            if (currentNode.locationx == goalX and currentNode.locationy == goalY):
                    goalFound = 1
                    break

            closedList.append(currentNode)
            #expand node - currently not checking the closed list
            if (currentNode.locationy &gt; 0): #can expand up
                frontier.append(Node(currentNode.locationx,currentNode.locationy - 1,currentNode))
            if (currentNode.locationy &lt; height - 1): #can expand down
                frontier.append(Node(currentNode.locationx,currentNode.locationy + 1,currentNode))
            if (currentNode.locationx &gt; 0): #can expand left
                frontier.append(Node(currentNode.locationx - 1,currentNode.locationy,currentNode))
            if (currentNode.locationx &lt; width -1): #can expand right
                frontier.append(Node(currentNode.locationx + 1,currentNode.locationy,currentNode))
            #done expanding

            currentNode = frontier.popleft()
            iterationCount += 1


    print currentNode.history
    print currentNode.locationx
    print currentNode.locationy

    printNodePathTrace(currentNode,width,height,mapTerrain,closedList)


if __name__ == '__main__':
    main()
</code></pre>
