When halving happens, there are two possible scenarios and only one is going to happen.

Either the miners will stop mining,as it will be unprofitable to be rewarded with half Bitcoins and sold at the same price, or they will continue and refuse to sell at the current exchange rate.   as long as they continue ,the price will inevitably rise as long as there is interest in buying as the available quantity will be smaller. Then they can start selling at a price to make a profit, as mining is quite expensive. As with all free assets, the price of Bitcoin depends solely on demand and supply.So far all halving has given more value to the price . As is well known,when the quantity of a good decreases or is limited , the demand increases as it is not unlimited,and the price rises considerably.Law of supply and demand.