trim_tickerlist is called from load_datafile.
trim_tickerlist will throw an index out of range error when parsing a ticker json file for a timerange outside its current contents.
This patch to load_datafile checks the timerange is in the file or not handles the exception by downloading the file with complete range. If the Exchange does not have the full range a message is logged and the file not sent to ticker-parse.
In summary, is json file does not have full requested time range
1. download file
2. if still missing time range, log and continue without ticker trim.
Here is an example of the error prior to path and after patching.
This is from binannce using the pair "ZEN/BTC" and timerange "20180522-20180523"
"""
File "/Users/creslin/PycharmProjects/freqtrade/freqtrade/optimize/__init__.py", line 107, in load_data
pairdata = load_tickerdata_file(datadir, pair, ticker_interval, timerange=timerange)
File "/Users/creslin/PycharmProjects/freqtrade/freqtrade/optimize/__init__.py", line 84, in load_tickerdata_file
pairdata = trim_tickerlist(pairdata, timerange)
File "/Users/creslin/PycharmProjects/freqtrade/freqtrade/optimize/__init__.py", line 36, in trim_tickerlist
while tickerlist[start_index][0] < start * 1000:
IndexError: list index out of range
""""
"""
2018-05-31 14:08:04,680 - freqtrade.optimize - INFO - Start timerange not in cached data
2018-05-31 14:08:04,680 - freqtrade.optimize - INFO - Download the pair: "ZEN/BTC", Interval: 5m
dumping json to "/Users/creslin/PycharmProjects/freqtrade/freqtrade/tests/testdata/ZEN_BTC-5m.json"
2018-05-31 14:08:08,225 - freqtrade.optimize - INFO - Start timerange unavailable from exchange
"""
