In that case I can understand why it's not a fit for Python. The risks you're describing are more what a brand new language would face: universal scope, impossible to measure success, no support plan... sounds like a nightmare in a mature product. If that's actually what it means to add a JIT to Python, the SC is doing its job by steering Python around this quixotic task.
reply> This is a runtime optimization/implementation detail.
I view JITs as a critical architectural component. Like you said, it impacts the whole system. Optimization and implementation details don't usually do that.
The problem is that “Python” the language includes native poorly isolated FFI interfaces exposed by CPython. So the language isn’t “Python” but CPython. That’s why alternate implementations like PyPy haven’t seen adoption despite having a very mature JIT while languages like JavaScript have JITs that put CPython’s performance to shame.
replyIt’s also part of why Python has been so successful in many domains. I was there for Python’s takeover of the data space, and I got quite used to porting things from Java (static, JIT, decent at multithreading) to Python (dynamic, interpreted, GIL) and realizing substantial performance improvements in the process.
replyIt’s kind of wild how nice Python’s C extension system, which enables basically zero cost interop with native code, is for certain purposes. It supports a situation that’s comparable to the games industry’s tradition of putting a Lua or Lisp tip on top of a C++ iceberg.
And yet, not introducing unnecessary chaos into the CPython project remains important.
replyPerhaps these priorities were always irreconcilable.
Perhaps that’s why the existence of competing Python JIT projects that weren’t trying to commit directly into CPython’s main branch kept coming up in the conversation.