Halving should mean a price increase, and arguably past halving events have led to increases, but the more it happens, the more people anticipate the same happening next time, and so buy up bitcoin ahead of the event, which drives up the price before the halving actually happens.
Quite true although on the long run, the halving effect will still have a positive impact on bitcoin price as it decrease the supply of bitcoin flowing into the market provided the optimism is still there. Irrespective of how the market plays out, it'll still be a win-win situation for bitcoin as the price is likely to raise before the event in anticipation of a appreciate in price after the event which is also likely to happen, the price decline that might follow should just be considered a correction because that's what it's not basically a dump. It's just an opportunity to buy more bitcoin.
If it raises before the event, we profit, and when it also raise after the event, we still profit.
@coingecko kudos for creating this infographic of bitcoin halving. Looks simple, very self explanatory and educative.