4.2.1 can break xeus-javascript

[davy39]

Description

Changes from 4.2.0 to 4.2.1 breaks xeus-javascript when installed in wasm-host together with xeus>=5.2.2 (contains libxeus.so).

Reproduce

name: kernel-wasm-host
channels:
  - https://repo.prefix.dev/emscripten-forge-dev 
  - https://repo.prefix.dev/conda-forge
  - conda-forge
dependencies:
  - xeus >=5.2.2
  - xeus-javascript

name: jupyter-host
channels:
  - https://repo.prefix.dev/conda-forge
  - conda-forge
dependencies:
  - notebook
  - jupyterlab
  - jupyterlite-xeus = 4.2.1
  - ipywidgets

jupyter lite serve --XeusAddon.prefix=/path/to/kernel-wasm-host

Try to launch the kernel and you'll get : TypeError: I.getDylinkMetadata is not a function
Load well when no libxeus.so present in kernel-wasm-host

Expected behavior

Javascript kernel should load, even with xeus installed.

Context

• JupyterLite version: Version 0.6.4
• Operating System and version: Linux Mint 21.3
• Browser and version: chrome

Browser Output

TypeError: I.getDylinkMetadata is not a function

[martinRenou]

Thanks for opening an issue. We indeed have some incompatibility between xeus and kernels starting with 5.2.3 that we are currently trying to mitigate.

Do you really need xeus in the WASM environment? xeus-javascript alone should work (famous last word)

[davy39]

Thanks for your reactivity. I would like to build an environment with all kernels I need to work, and xeus-cpp comes with xeus.
Finally, after days of struggling I've realized that my problem was not from the Ocaml kernel I'm developing, but a jupyterlite-xeus issue...

Anyway, most important is I've found a working config : https://davy39.github.io/my_juperterlite/ 🥳

By the way, I've found that xeus-javascript + ipycanvas was leading to same bug : TypeError: I.getDylinkMetadata is not a function even with jupyterlite-xeus = 4.2.0

Thanks for your work !

[martinRenou]

Makes sense :) You seem to be in the exact situation we are trying to mitigate this week 😬

We have a quick patch in mind that should come today

[martinRenou]

I've briefly looked at your setup. You may have been lucky to find a configuration that looks like it's working, but I'm 100% sure there will be issues.

jupyterlite-xeus provides a way to specify multiple environments, I believe you should split environments as following:

• One for xeus-python and its packages (ipycanvas, matplotlib, numpy whatever)
• One for xeus-ocaml alone (really cool BTW)
• One for xeus-javascript alone
• One for xeus-cpp alone
• One for xeus-sqlite alone

[martinRenou]

Long term we'll have a better approach for mixing kernel in the same env, but today it doesn't work well. They are conflicting since we load all shared libraries from the environment at runtime, not only the ones that are needed

[DerThorsten]

I just released xeus-javascript 0.4.1.
The error TypeError: I.getDylinkMetadata is not a function should be fixedf with it

[davy39]

Great, thank you ! I adapt your work to and it work as well with last jupyterlite-xeus see here.