Comment by crabbone

Oh, it's not just a performance optimization. But you've said it yourself: "a new python interpreter and compiler". A lot of Python code out there lives with assumptions of CPython interpreter built into it. Pretty sure pytest would've been affected, should JIT replace the existing interpreter, for example.

Anyways. I don't believe that Python needs a JIT compiler. I don't believe that CPython can realistically replace its interpreter with JIT compiler without causing major problems with the community packages.

The way I see it: Python users today desperately want Java. They want it called Python because there's some vague memory still around of Python being cool and Java not being cool.

In Russian there's a children tale about a hungry soldier returning from a war and a greedy old woman who offered him a bed for the night. The old woman then pretends to have no food for dinner, and a soldier promises her a magic trick of making a porridge out of a hatchet. And so he tells the woman to put a pot on a stove with a hatchet in it, and step by step he makes her add all the ingredients necessary to make a porridge to the pot. The story gave birth to the idiom "hatchet porridge", which is used to describe anything that was created in a similar way: by deception, when another goal was allegedly being pursued.

So, to me, the current state of Python is this "hatchet porridge". None of its users want the actual Python (the hatchet is still sticking out of the pot), and they keep adding Java ingredients to the pot in hopes to cook up Java. And so was JIT. It just turned out to be too difficult to throw away the hatchet. An the porridge still has some chipped wood in it as well as a metallic taste.