Vote to promote Ken Jin (Fidget-Spinner)

Guido and I want to propose promoting Ken Jin as a core developer.

  • Promote Ken Jin
  • Don’t promote Ken Jin

0 voters

I have been mentoring Ken Jin for a long time (I previously gave him triage privileges time ago). Ken has been very active in the project, actively reviewing pull requests and fixing bugs (some of them notably complex) and he has been contributing both to code and documentation. He is a very enthusiastic and energetic person and during this time he has made great progress in learning the CPython workflow, CPython internals and how to keep things maintainable and backwards compatible. He also has actively participated in many important areas such as Python performance and typing (see below).

Ken has been working with Guido for quite some time as well, specially in the typing module and in typing related PEPs. During this time he has also prove to be quite proficient in writing clear documentation and in doing useful reviews of it.


Selected contribution highlights



Faster CPython project

  • Researched and implemented CALL_FUNCTION opcode specialization via PEP 659 (Specializing Adaptive Interpreter) with lots of help from Mark. PR unmerged, we’re still trying to assess whether it’s worth the maintenance cost, and we’re waiting for other optimizations in CPython.
  • Researched viability of specializing FOR_ITER opcode. Temporarily dropped because common cases slowed down, and 10% faster for long loops doesn’t justify the complexity.
  • Researched viability of specializing LOAD_METHOD opcode. Still a WIP, but more promising than the other two.

Post-promotion mentoring

As it was done in previous promotions we will continue to mentor him for one month after his promotion (if it’s accepted) to help him to deal with his new responsibilities, and we plan to require him to ask us before merging anything until he will be used to the process.

Vote process

As a reminder from PEP 13 regarding voting rules:

It is granted by receiving at least two-thirds positive votes in a core team vote that is open for one week and with no veto by the steering council.


I have been mentoring Ken Jin for some time. He started out showing interest in improving documentation for the typing module, but quickly he started writing code for it too, fixing bugs, and then branched out to other topics.

In fact, I had wanted to promote him around the time of the Language Summit this spring, but Ken Jim himself told me he did not feel ready then. I’m glad he’s changed his mind now. :slight_smile:

More recently I have actually given him considerable freedom and I have asked and valued his opinion on various topics where I felt I didn’t have time to dive in deeply myself.

Ken is clearly here to stay.


+1 for me!

Aaaaah Fidget-Spinner, I know him! I saw his name often on GitHub pull requests. I’m less used to his real name Ken Jin :slight_smile: His comments are always relevant and useful. I have a good experience of working with him.


I have with worked Fidget-Spinner (aka Ken Jin) over multiple bug reports. Ken brings amazing communication skills to the table and is very quick in addressing feedback.

Thank you for your contributions, Ken.


I’ve had chance to interact with them on multiple topics (including different parts of the project like the compiler, and some windows related issues), and the experience of working with them was really nice. +1 from me as well!


The poll is now closed with unanimous approval from 31 voters, and I have now emailed the Steering Council to ask for their approval.

Thank you to everyone who voted!


I’m extremely grateful to the community around Python - a community I feel is creative, welcoming and funny (which other language has an entire page for jokes[1]? :slight_smile: ) I’m happy to have the opportunity to contribute more to CPython.

I couldn’t have asked for better mentors. Guido and Pablo were extremely patient and gave me a lot of freedom to explore. I’m thankful for their guidance and I hope to continue in their spirit for future contributors to Python.

Last but not least, the numerous core devs I’ve interacted with have always taught me something new.
I still have much left to learn, and I’m looking forward to learning much more from everyone!

Thank you!


[1] Python Humor |


Somehow I went all this time without knowing this joke page existed, haha. Thanks for sharing and welcome to the core team! :slight_smile:

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