Drop lerna

[jtpio]

References

Similar to jupyterlite/jupyterlite#1843

Trying to see if we can do without lerna to help simplify the dev setup and remove many dependencies from the yarn.lock.

Closes #7828
Closes #7831

Code changes

• Drop lerna and nx
• Fix custom script for bumping versions
• Check if we need the yarn workspaces plugin

User-facing changes

None

Backwards-incompatible changes

None

[github-actions]

👈 Launch a Binder on branch jtpio/notebook/drop-lerna

[Copilot]

Pull request overview

This PR removes the repository’s Lerna/Nx-based monorepo tooling and replaces the related workflows with Yarn workspaces–driven scripts plus custom buildutils helpers for versioning and packaging.

Changes:

• Remove lerna, nx, and associated configuration; shrink yarn.lock accordingly.
• Replace Lerna/Nx-driven build/test/release commands with workspace-based scripts and new buildutils CLIs (set-workspace-version, npm-pack, updated release:* flows).
• Adjust TypeScript project references and package dependencies to reflect the updated workspace/build graph, and update CI workflows to use jlpm flows.

Reviewed changes

Copilot reviewed 20 out of 21 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
yarn.lock	Drops transitive dependency graph introduced by Lerna/Nx and related tooling.
package.json	Replaces Lerna scripts with workspace-based build/test/watch commands; adds workspace version setter.
lerna.json	Removed (Lerna no longer used).
nx.json	Removed (Nx task caching no longer used).
pyproject.toml	Updates hatch/jupyter-releaser scripts to use new Node utilities instead of Lerna.
CONTRIBUTING.md	Removes documentation section about Lerna/Nx task caching.
buildutils/src/utils.ts	Adds workspace package discovery/version syncing + pack helper utilities.
buildutils/src/release-bump.ts	Reworks version bump logic to use Hatch + workspace version syncing (no Lerna).
buildutils/src/release-patch.ts	Reworks patch release flow to use Hatch + workspace version syncing (no Lerna).
buildutils/src/set-workspace-version.ts	New CLI to align workspace package versions to a provided version.
buildutils/src/npm-pack.ts	New CLI to npm pack all public workspaces.
packages/tree/package.json	Removes dependency on @jupyter-notebook/application.
packages/tree/tsconfig.json	Removes TS project reference to ../application.
packages/tree-extension/package.json	Removes dependency on @jupyter-notebook/application.
packages/tree-extension/tsconfig.json	Updates TS project reference from ../application to ../tree.
packages/notebook-extension/tsconfig.json	Adds TS project reference to ../application.
packages/documentsearch-extension/tsconfig.json	Adds TS project reference to ../application.
packages/lab-extension/package.json	Removes Nx targets metadata from package manifest.
app/package.json	Removes @jupyterlab/buildutils devDependency.
.github/workflows/buildutils.yml	Updates versioning workflow to use new workspace versioning/release scripts.
.github/workflows/build.yml	Switches lint job Node setup from global yarn to jlpm + JupyterLab install.

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[Copilot]

The update:dependency script still passes --lerna to @jupyterlab/buildutils/lib/update-dependency.js, but this PR removes lerna.json and drops Lerna from the toolchain. If the script uses Lerna configuration to discover packages, this will now fail (or at least be misleading). Consider switching this to the non-Lerna mode (or an explicit workspace-based option) so dependency updates don’t rely on removed Lerna config.

Suggested change

	"update:dependency": "node ./node_modules/@jupyterlab/buildutils/lib/update-dependency.js --lerna",
	"update:dependency": "node ./node_modules/@jupyterlab/buildutils/lib/update-dependency.js",