LSP server

[0xGeorgii]

Confidence Score: 5/5

The PR is safe to merge — it adds a substantial new LSP server and IDE stack with no regressions to existing code paths.

All core paths — URI conversion, position encoding, diagnostics publishing, the shutdown handshake, and the VS Code lifecycle queue — are correctly implemented and well-covered by tests. The one behavioral edge case (inlay hints falling back to the whole file when a viewport range extends past the last line) is harmless in practice and does not affect correctness for any standard editor flow.

apps/lsp/src/handlers.rs — the inlay_hint range fallback is the only area worth a follow-up look before the feature ships to end users.

Important Files Changed

Filename	Overview
apps/lsp/src/server.rs	New: single-threaded message loop with inline shutdown handshake, request dispatch, and dependent-document republish logic; well-tested with unit coverage of all notification paths.
apps/lsp/src/handlers.rs	New: per-request and per-notification handlers; inlay_hint silently falls back to returning all hints when the viewport range is out of bounds (text_range returns None).
apps/lsp/src/uri.rs	New: hand-rolled file URI ↔ path conversion with explicit Windows drive-letter handling; comprehensive round-trip tests including percent-encoding, backslash, and query/fragment rejection.
apps/lsp/src/convert.rs	New: byte-offset ↔ LSP position/range conversion and IDE→LSP type mappings; every variant is covered explicitly and tested.
ide/ide-db/src/database.rs	New: RootDatabase with closure-aware invalidation; open/change/close correctly handles the newly-available widening case for missing imports.
ide/ide-db/src/hit_test.rs	New: file-scoped AST hit-testing that descends to the smallest covering node; correctly guards against zero-width default locations claiming offset 0.
ide/ide-db/src/analysis.rs	New: FileAnalysis computes type-check, analysis rules, and per-closure file metadata once; closure_paths always includes the entry path to prevent permanent cache poisoning.
ide/vfs/src/lib.rs	New: path-interner plus in-memory overlay; no I/O, idempotent interning, correct overlay lifecycle.
editors/vscode/src/lsp/client.ts	New: serialized LSP lifecycle management via a promise queue; doStop sets client=undefined before awaiting stop so re-entry is safe; correctly disposes the client on deactivation.
editors/vscode/src/lsp/resolve.ts	New: pure binary-resolution helper (settings → managed path → PATH); vscode-free so it is directly unit-testable; correctly refuses to fall back when an explicit path is non-executable.
ide/ide/src/lib.rs	New: AnalysisHost/Analysis facade exposing all IDE features by path; closure_line_index reuses the document's already-computed analysis for cross-file position conversion.
apps/lsp/src/main.rs	Modified: spawns the server loop on a 64 MiB stack thread (mirrors rust-analyzer) to prevent deep-AST stack overflows on pathological inputs.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant Editor as VS Code Editor
    participant Client as LSP Client (client.ts)
    participant Server as inference-lsp (server.rs)
    participant Handler as handlers.rs
    participant IDE as AnalysisHost (ide/src/lib.rs)
    participant DB as RootDatabase (ide-db/src/database.rs)
    participant VFS as Vfs (vfs/src/lib.rs)

    Editor->>Client: activate extension
    Client->>Server: initialize (stdio)
    Server-->>Client: capabilities (FULL sync, hover, def, completion, symbols, hints)

    Editor->>Client: didOpen(uri, text)
    Client->>Server: textDocument/didOpen
    Server->>Handler: did_open(params)
    Handler->>IDE: open_document(path, text)
    IDE->>DB: open_document(path, text)
    DB->>VFS: set_contents(id, text)
    DB->>DB: invalidate dependent analyses
    Handler->>IDE: analysis().diagnostics(path)
    IDE->>DB: analysis(path) compute and memoize FileAnalysis
    DB-->>IDE: FileAnalysis
    IDE-->>Handler: Vec Diagnostic
    Handler-->>Server: PublishDiagnosticsParams plus dependents
    Server->>Client: textDocument/publishDiagnostics x N open docs

    Editor->>Client: hover request
    Client->>Server: textDocument/hover
    Server->>Handler: hover(params)
    Handler->>IDE: analysis().line_index(path)
    Handler->>IDE: analysis().hover(path, offset)
    IDE-->>Handler: Option Hover
    Handler-->>Server: Option Hover
    Server-->>Client: result

    Editor->>Client: didClose(uri)
    Client->>Server: textDocument/didClose
    Server->>Handler: did_close(params)
    Handler->>IDE: close_document(path)
    IDE->>VFS: remove_contents(id)
    Handler-->>Server: empty PublishDiagnosticsParams
    Server->>Client: textDocument/publishDiagnostics clear diagnostics

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
    participant Editor as VS Code Editor
    participant Client as LSP Client (client.ts)
    participant Server as inference-lsp (server.rs)
    participant Handler as handlers.rs
    participant IDE as AnalysisHost (ide/src/lib.rs)
    participant DB as RootDatabase (ide-db/src/database.rs)
    participant VFS as Vfs (vfs/src/lib.rs)

    Editor->>Client: activate extension
    Client->>Server: initialize (stdio)
    Server-->>Client: capabilities (FULL sync, hover, def, completion, symbols, hints)

    Editor->>Client: didOpen(uri, text)
    Client->>Server: textDocument/didOpen
    Server->>Handler: did_open(params)
    Handler->>IDE: open_document(path, text)
    IDE->>DB: open_document(path, text)
    DB->>VFS: set_contents(id, text)
    DB->>DB: invalidate dependent analyses
    Handler->>IDE: analysis().diagnostics(path)
    IDE->>DB: analysis(path) compute and memoize FileAnalysis
    DB-->>IDE: FileAnalysis
    IDE-->>Handler: Vec Diagnostic
    Handler-->>Server: PublishDiagnosticsParams plus dependents
    Server->>Client: textDocument/publishDiagnostics x N open docs

    Editor->>Client: hover request
    Client->>Server: textDocument/hover
    Server->>Handler: hover(params)
    Handler->>IDE: analysis().line_index(path)
    Handler->>IDE: analysis().hover(path, offset)
    IDE-->>Handler: Option Hover
    Handler-->>Server: Option Hover
    Server-->>Client: result

    Editor->>Client: didClose(uri)
    Client->>Server: textDocument/didClose
    Server->>Handler: did_close(params)
    Handler->>IDE: close_document(path)
    IDE->>VFS: remove_contents(id)
    Handler-->>Server: empty PublishDiagnosticsParams
    Server->>Client: textDocument/publishDiagnostics clear diagnostics

Loading

_{Reviews (2): Last reviewed commit: "more tests" | Re-trigger Greptile}

Context used:

• Rule used - When reviewing LSP server code in this repo, prefe... (source)

[codecov]

Codecov Report

❌ Patch coverage is 96.82931% with 180 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
ide/ide/src/goto_definition.rs	85.75%	55 Missing ⚠️
ide/ide/src/hover.rs	91.33%	24 Missing ⚠️
core/inference/src/project.rs	95.80%	20 Missing ⚠️
ide/ide/src/completions.rs	93.81%	18 Missing ⚠️
apps/lsp/src/server.rs	94.62%	13 Missing ⚠️
apps/lsp/src/handlers.rs	94.28%	10 Missing ⚠️
ide/ide-db/src/hit_test.rs	98.67%	8 Missing ⚠️
ide/ide/src/diagnostics.rs	97.32%	7 Missing ⚠️
apps/infs/src/toolchain/doctor.rs	97.05%	4 Missing ⚠️
apps/infs/src/toolchain/paths.rs	97.18%	4 Missing ⚠️
... and 7 more

📢 Thoughts on this report? Let us know!