Revert the jlpm update for JupyterLab 4.1?

[jtpio]

#15295 updated the yarn used by jlpm to version 3.6.4.

#15295 also includes some discussions on how this affects extension repos and other repos using the jlpm command.

For example the release of JupyterLab 4.1.0a4 required updating the yarn.lock in the Notebook repo, as the Notebook CI started to fail shortly after the release: jupyter/notebook#7170

This is expected to be the same for most extension repos using jlpm.

The question is: should we revert this change in JuyterLab 4.1 to avoid disrupting third-party extensions workflows too much?

Technically the fix is not too difficult and was documented in jupyter/notebook#7170. But it's still an annoyance to extension authors and if we can avoid it it may be better.

cc @krassowski @fcollonval @bollwyvl since you commented in jupyter/notebook#7170.

[bollwyvl]

Maybe there is a way to put something in @jupyterlab/builder that would transparently heal these kinds of things?

[jtpio]

Maybe there is a way to put something in @jupyterlab/builder that would transparently heal these kinds of things?

Doing some automatic repairs would be nice, but not sure to see how this would prevent CI builds from failing? (as illustrated in the previous discussion)

Also @jupyterlab/builder might not necessarily be "in sync" with the jupyterlab Python package (which provides jlpm). For example an extension can depend on @jupyterlab/builder@^4.0.9 with 4.0.9 in its lock, while the latest jupyterlab stable release will at some point be 4.1.

[krassowski]

Maybe we could remove pnp plugin from jlpm using yarnpkg/berry#2384 (comment) which would remove the patch and hash issue altogether? Since all we can do is manipulate jlpm in 4.1, we could make it inject a preinstall script which removes the hash... but this assumes that downstream did not want to use it which is not something we would know.

[ericsnekbytes]

During triage we decided to revert this change.

Triage Notes:

• We can print messages in the install script to inform extension devs
• Option: Revert the last yarn update...or ship both versions