I am personally entirely anti-violence, outside of immediate situations requiring self-defence, or the defence of someone in proximity to you that you have the ability to protect.
If I had kids, which I don't, nor plan to, I'd definitely not give them any sort of pain-based punishment, I find the idea personally abhorrent.
That being said - I am sure there are many well-adjusted human beings with loving parents who were spanked, and gave spankings as well as many wretched arseholes, who were not.
I don't know why so many people feel so strongly about this, as if it's the one thing that's going to make or break a child.
My anecdotal corporal punishment story was I recall being hit on the hand by a teacher, with a metal ruler. I still fume about this today: the violation I felt has coloured my life from that moment forward, and not in a good way. I know this sounds dramatic, and I don't mean to be, just pointing out that the result of a brief instance inflicting pain on a human being can have wildly varying consequences, obviously. In my case, it engendered in me a profound distrust of authority, which led to a cascade of extremely bad life decisions, let me tell you...
Perhaps I should have been hurt more? \_(ツ)_/¯