Display failure message when simulations return invalid timestamps

[steven-cd]

The results for one of the simulations I gave during the last JBC demo cannot be viewed, instead giving an Internal Server Error (https://covid-modelling-stg.epcc.ed.ac.uk/simulations/11?model=mrc-ide-covid-sim). I don't know what about this simulation is different that could have caused that. Other models for the same simulation work okay, e.g. https://covid-modelling-stg.epcc.ed.ac.uk/simulations/11?model=basel

[steven-cd]

Okay, I've got far enough down the chain to identify that the data produced by CovidSim for this simulation had 0s for everything, including the timestamps (i.e. the data had timestamps: [0, 0, 0, 0, ...] instead of the expected timestamps: [1, 2, 3, 4, ...]. This seems to be in the output from CovidSim itself (in results.avNE.severity.xls). I'm not sure there's much point debugging this much further - I suspect it would be more fruitful to work on upgrading CovidSim first before seeing if it can be recreated.

The UI was not designed to cope with this, and it results in unexpectedly undefined variables - I put in some changes locally to ignore these, which then gives a view like:

That's not ideal, but is probably better than breaking the app altogether.

I feel like there's probably a better solution however - detecting the problem earlier on either in the web-ui or in the model-runner, in order to display a "Failed" message

[steven-cd]

I've committed my work-around as b6d3607, but I think it is worth leaving the issue open in order to come up with a better approach and/or fix the underlying issue