feat: LSP root and document URI integration from backend

[daizutabi]

📝 Summary

Closes #8662

This PR implements the frontend integration for the LSP workspace information provided by PR #9019. It updates all language server clients (pylsp, ty, pyrefly, basedpyright) to use the backend-resolved rootUri and workspaceFolders instead of computing them on the frontend.

Changes

1. LSP Utility Functions Migration

File: frontend/src/core/codemirror/lsp/utils.ts

Replaced frontend-side path computation with backend-provided values:

• getLspRootUri(): Returns the backend-provided rootUri from lspWorkspaceAtom
• getLspWorkspaceFolders(): Constructs workspace folders array from rootUri
• getLspDocumentUri(): Returns the backend-provided documentUri from lspWorkspaceAtom

2. Language Server Client Updates

File: frontend/src/core/codemirror/language/languages/python.ts

Updated all four LSP clients with consistent initialization:

• pylspClient: Uses new getLspRootUri() and getLspWorkspaceFolders()
• tyLspClient: Uses new getLspRootUri() and getLspWorkspaceFolders()
• pyreflyClient: Uses new getLspRootUri() and getLspWorkspaceFolders()
• pyrightClient: Uses new getLspRootUri() and getLspWorkspaceFolders()

Verification (Screenshots)

Verified using a root pyproject.toml with:

[tool.basedpyright]
reportUnusedCallResult = false

Before

The project configuration is ignored because the workspace root was not specified. basedpyright incorrectly reports a warning on line 4 (func()) despite it being disabled in pyproject.toml.

After

The configuration is now correctly applied. The warning on line 4 is suppressed, while a legitimate type error (line 2) is still reported.

📋 Pre-Review Checklist

• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
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✅ Merge Checklist

• I have read the contributor guidelines.
• Documentation has been updated where applicable, including docstrings for API changes.
• Tests have been added for the changes made.

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Apr 13, 2026 9:12am

[codecov]

Bundle Report

Changes will increase total bundle size by 95 bytes (0.0%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
marimo-esm	24.84MB	95 bytes (0.0%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: marimo-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
assets/cells-*.js	95 bytes	703.48kB	0.01%

Files in assets/cells-*.js:

• ./src/core/codemirror/lsp/utils.ts → Total Size: 421 bytes

• ./src/core/codemirror/language/languages/python.ts → Total Size: 6.66kB

• ./src/core/codemirror/lsp/notebook-lsp.ts → Total Size: 17.91kB

• ./src/core/codemirror/lsp/federated-lsp.ts → Total Size: 4.29kB

[Copilot]

Pull request overview

Integrates backend-resolved LSP workspace information (root/document URIs) into the frontend so Python language servers use the correct project root (e.g., to pick up pyproject.toml-based basedpyright settings).

Changes:

• Replaced frontend-derived LSP root/document URI computation with values read from lspWorkspaceAtom.
• Updated Python LSP client initialization (pylsp/ty/pyrefly/basedpyright) to pass backend rootUri and derived workspaceFolders.
• Updated LSP client wrappers/tests to use the backend-provided documentUri.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
frontend/src/core/codemirror/lsp/utils.ts	Adds helpers to read backend-provided rootUri / documentUri from Jotai store.
frontend/src/core/codemirror/lsp/notebook-lsp.ts	Switches merged document URI source to getLspDocumentUri().
frontend/src/core/codemirror/lsp/federated-lsp.ts	Switches federated client document URI source to getLspDocumentUri().
frontend/src/core/codemirror/lsp/tests/notebook-lsp.test.ts	Adjusts test setup/expectations for backend-provided document URI.
frontend/src/core/codemirror/language/languages/python.ts	Initializes all Python LSP clients with backend rootUri + workspace folders.