refactor(lsp): tools can report diagnostics for other uris too

[Sysix]

This PR refactors the LSP tool diagnostic API to allow tools to report diagnostics for multiple URIs, not just the file being analyzed. This enables cross-file analysis features like ts config deprecation detection.

[Sysix]

• refactor(lsp): tools can report diagnostics for other uris too #16783 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

This PR refactors the LSP tool diagnostic API to allow tools to report diagnostics for multiple URIs, not just the file being analyzed. This enables cross-file analysis features like import cycle detection where a tool analyzing one file may need to report issues in related files.

Key changes:

• Introduces DiagnosticResult type alias as Vec<(Uri, Vec<Diagnostic>)> to return diagnostics for multiple URIs
• Updates all diagnostic trait methods to return DiagnosticResult instead of Option<Vec<Diagnostic>>
• Adds collect_diagnostics_with aggregation helper in WorkspaceWorker to merge diagnostics from multiple tools
• Updates backend to use publish_all_diagnostics helper for publishing multi-URI diagnostic results

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
crates/oxc_language_server/src/tool.rs	Defines new DiagnosticResult type and updates trait method signatures to return multi-URI diagnostics
crates/oxc_language_server/src/worker.rs	Adds collect_diagnostics_with aggregator and refactors diagnostic methods to handle multi-URI results
crates/oxc_language_server/src/tests.rs	Updates fake tool implementation to return diagnostics using new tuple structure
crates/oxc_language_server/src/linter/tester.rs	Adds snapshot helpers for multi-URI diagnostic results
crates/oxc_language_server/src/linter/server_linter.rs	Implements new trait interface by wrapping single-file diagnostics in Vec with URI
crates/oxc_language_server/src/backend.rs	Updates diagnostic publishing to use publish_all_diagnostics helper for multi-URI results
crates/oxc_language_server/src/linter/snapshots/*.snap	Updates snapshot test outputs to include "File URI" prefix for each file's diagnostics

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[charliecreates]

The new multi-URI diagnostic plumbing is solid, but a few behavioral edges need tightening: aggregation order is nondeterministic due to HashMap iteration, snapshot URI scrubbing can now panic!() for non-file:///non-repo URIs, and the tester output conflates “ignored” with “no diagnostics.” Additionally, the backend appears to have dropped LSP diagnostic version publication for did_open/did_change, which can cause stale diagnostics if publish_all_diagnostics doesn’t preserve versions.

Additional notes (1)

• Compatibility | crates/oxc_language_server/src/backend.rs:510-510
  In did_open / did_change, the old flow published diagnostics with a version (Some(params.text_document.version)), but the new flow calls publish_all_diagnostics(diagnostics) without passing the version.

If publish_all_diagnostics doesn’t incorporate the document version, clients may receive diagnostics that apply to a different buffer version (especially with on-type linting), which can lead to stale/incorrect squiggles.

This is a behavior change; it should be intentional and verified.

Summary of changes

Summary of changes

Multi-URI diagnostics support

• Introduced DiagnosticResult = Vec<(Uri, Vec<Diagnostic>)> in crates/oxc_language_server/src/tool.rs.
• Updated Tool::{run_diagnostic, run_diagnostic_on_save, run_diagnostic_on_change} to return DiagnosticResult (defaulting to an empty vector) instead of Option<Vec<Diagnostic>>.

Worker aggregation changes

• Refactored WorkspaceWorker to aggregate diagnostics across tools and URIs via collect_diagnostics_with, merging results into a per-Uri collection (HashMap<Uri, Vec<Diagnostic>>).
• Updated all worker diagnostic entry points (run_diagnostic*) to return multi-URI results.

Backend publishing flow

• Updated backend call sites (did_open, did_change, did_save, and initial workspace scan) to consume multi-URI results and publish via publish_all_diagnostics.

Linter and tests/snapshots

• Updated ServerLinter to wrap single-file lint results into vec![(uri.clone(), diagnostics)].
• Updated snapshot formatting to include Linted file: and per-entry File URI: headers; added URI “scrubbing” helper for deterministic snapshots.
• Updated fake tool and worker tests to assert against the new (Uri, Vec<Diagnostic>) structure.

[camc314]

Merge activity

• Dec 13, 3:00 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Dec 13, 3:00 PM UTC: camc314 added this pull request to the Graphite merge queue.
• Dec 13, 3:05 PM UTC: Merged by the Graphite merge queue.