[ark] kernel_info_request not getting kernel_info_reply

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[ark] kernel_info_request not getting kernel_info_reply #3864

Open rgbkrk opened 2 months ago

rgbkrk commented 2 months ago

I'm trying out the Ark kernel with my Zed PR (https://github.com/zed-industries/zed/pull/13625) and running into an issue with Ark no longer able to respond to execute_requests after a kernel_info_request is sent. Since it seems to work well in the classic Jupyter notebook, this is probably on my end. My shell socket is stuck waiting for a kernel_info_reply that never comes. Meanwhile I do get the status: busy and status: idle messages on the IOPUB channel. If I just don't send a KernelInfoRequest then all is well.

juliasilge commented 2 months ago

Do we think this needs to get added to #2264 for Jupyter compatibility, or is this likely a Zed problem?

rgbkrk commented 2 months ago

It feels like I could do our (Zed's) shell signal handling a bit different. Basically, I'm waiting for a kernel_info_reply on our shell channel that just never comes in. I see that ark receives my kernel_info_request (based on the logs). Going to try some things and report back.

DavisVaughan commented 2 months ago

@rgbkrk I haven't looked into it in detail yet, but the only things worth immediately noting are:

We block until R has completely started up before sending back the kernel_info_reply (so we can send back an appropriate banner and because it seems like the right thing to do)
We include an extra positron field in the language_info, but I think the protocol allows this and consumers should just be ignoring this

https://github.com/posit-dev/ark/blob/fed7fa4cab33160582833c6f0ea713c145aff7c1/crates/ark/src/shell.rs#L149