Halving won't happen on 2019 but on 2020.
It may cause a bull run or not an actual bull run but the effect that it made for the first two halving is positive. But take a look on the market now I'm just feeling excited every time we are hitting the next hundred level but isn't this good that bitcoin reached $6,600 again while most alts follows again.
For a while now that we have had the two halving in the past, the chances of a bull run is something that is plausible but since we cannot always just ascertain the future we cannot see because of something that happened in the past, we just have to be patient.
However, it is, if the bull run occurs every one will see it, and trying to imagine what would be of bitcoin about 2 years before the next halving is something that I really do not always see as a thing anyone should be doing at all.
It is actually a good thing to see bitcoin making some moves at the moment towards the bullish side and I guess we just have to be patient to see how the market really or eventually breaks out from here but the way things are; I am really hopeful it would be upward before the end of December.