Using redbaron to find sort and sorted using cmp so we can convert them to key for python 3

find_cmp_sorts

from redbaron import RedBaron
import os
import sys
import io

def is_bad_sort(node):
    # must be .method invocation
    if node.parent.type != 'atomtrailers':
        return False

    # not a function invocation
    if node.index_on_parent == 0:
        return False

    # must be called()
    if node.next is None or node.next.type != 'call':
        return False

    call = node.next
    arglist = call.value

    # if it doesn't have any arguments, its fine
    if len(arglist) == 0:
        return False

    # first argument is not a kvarg, must be comparator
    if arglist[0].target is None:
        return True
    
    # all kvargs, try to find cmp in them
    for arg in arglist:
        if arg.target.value == "cmp":
            return True

    return False


def is_bad_sorted(node):
    # must be function invocation
    if node.parent.type != 'atomtrailers':
        return False

    if node.index_on_parent != 0:
        return False

    # must be called()
    if node.next is None or node.next.type != 'call':
        return False

    call = node.next
    arglist = call.value

    # if it only has one argument, its fine
    if len(arglist) <= 1:
        return False

    # second argument is not a kvarg, must be comparator
    if arglist[1].target is None:
        return True
    
    # second argument is a kvarg, so try to find cmp in
    # any remaining args
    for arg in arglist[1:]:
        if arg.target.value == "cmp":
            return True

    return False

def process(src):
    """
    >>> process('x.sort(d)')
    '1:x.sort(d)'
    >>> process('x.sort()')
    ''
    >>> process('sort(d)')
    ''
    >>> process('x.sort(cmp=c)')
    '1:x.sort(cmp=c)'
    >>> process('x.sort(reverse=True, cmp=c)')
    '1:x.sort(reverse=True, cmp=c)'
    >>> process('x.sort(d, c)')
    '1:x.sort(d, c)'
    >>> process('x.sorted(d)')
    ''
    >>> process('sorted(x, cmp)')
    '1:sorted(x, cmp)'
    >>> process('sorted(x)')
    ''
    >>> process('sorted(x, reverse=True, cmp=c)')
    '1:sorted(x, reverse=True, cmp=c)'
    """
    output = io.BytesIO()
    for sort in RedBaron(src).find_all('name', value='sort'):
        if is_bad_sort(sort):
            output.write("%d:%s" %
                (sort.absolute_bounding_box.top_left.line, sort.parent))

    for sort in RedBaron(src).find_all('name', value='sorted'):
        if is_bad_sorted(sort):
            output.write("%d:%s" %
                (sort.absolute_bounding_box.top_left.line, sort.parent))

    return output.getvalue()


if __name__ == "__main__":
    if len(sys.argv) > 1:
        for f in sys.argv[1:]:
            s = process(open(f).read())
            if s:
                print f
                print s
    else:
        import doctest
        doctest.testmod()