holtWintersAbberation: list index out of range

[Dieterbe]

Hi all, I have a series which renders fine, and all other holtwinters functions work fine
(see https://snapshot.raintank.io/dashboard/snapshot/fXMjSfEzZd4dwC0mO7LNTDM5CR3R1x7N)
but When I use holtWintersAbberation(<series>,3) (or pass 1 or 2 as arg, same outcome) I get the below:

Traceback (most recent call last):
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/flask/app.py", line 1988, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/flask/app.py", line 1641, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/flask/app.py", line 1544, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/flask/app.py", line 1639, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/flask/app.py", line 1625, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/graphite_api/app.py", line 416, in render
    series_list = evaluateTarget(context, target, data_store)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/graphite_api/evaluator.py", line 73, in evaluateTarget
    result = evaluateTokens(requestContext, tokens, data_store)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/graphite_api/evaluator.py", line 105, in evaluateTokens
    replacements)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/graphite_api/evaluator.py", line 139, in evaluateTokens
    ret = func(requestContext, *args, **kwargs)
  File "/usr/share/python/graphite/local/lib/python2.7/site-packages/graphite_api/functions.py", line 2600, in holtWintersAberration
    elif upperBand[i] is not None and series[i] > upperBand[i]:
IndexError: list index out of range

			

I have marked the offending line 2600 below:

def holtWintersAberration(requestContext, seriesList, delta=3):
    """
    Performs a Holt-Winters forecast using the series as input data and plots
    the positive or negative deviation of the series data from the forecast.
    """
    results = []
    for series in seriesList:
        confidenceBands = holtWintersConfidenceBands(requestContext, [series],
                                                     delta)
        lowerBand = confidenceBands[0]
        upperBand = confidenceBands[1]
        aberration = list()
        for i, actual in enumerate(series):
            if series[i] is None:
                aberration.append(0)
            elif upperBand[i] is not None and series[i] > upperBand[i]: <-- line 2600
                aberration.append(series[i] - upperBand[i])
            elif lowerBand[i] is not None and series[i] < lowerBand[i]:
                aberration.append(series[i] - lowerBand[i])
            else:
                aberration.append(0)

        newName = "holtWintersAberration(%s)" % series.name
        results.append(TimeSeries(newName, series.start, series.end,
                                  series.step, aberration))
    return results