sdk/pkg/analysis_server/tool/lsp_spec

Language Server Protocol

Language Server Protocol (LSP) support is available in the Dart analysis server from version 2.2.0 of the SDK (which was included in version 1.2.1 of Flutter). The supported messages are detailed below (for the version of the SDK that matches this README).

Using the Dart LSP server in editors

• Using Dart LSP in Vim

Running the Server

Run the server from source to ensure you're running code that matches the status shown below. If you don't have a locally built SDK then a recent nightly should do. Pass the --lsp flag to start the server in LSP mode:

dart pkg/analysis_server/bin/server.dart --lsp

Note: In LSP the client makes the first request so there is no obvious confirmation that the server is working correctly until the client sends an initialize request. Unlike standard JSON RPC, LSP requires that headers are sent.

Initialization Options

• onlyAnalyzeProjectsWithOpenFiles: When set to true, analysis will only be performed for projects that have open files rather than the root workspace folder. Defaults to false.
• suggestFromUnimportedLibraries: When set to false, completion will not include synbols that are not already imported into the current file. Defaults to true, though the client must additionally support workspace/applyEdit for these completions to be included.

Method Status

Below is a list of LSP methods and their implementation status.

• Method: The LSP method name
• Basic Impl: This method has an implementation but may assume some client capabilities
• Capabilities: Only types from the original spec or as advertised in client capabilities are returned
• Tests: Has automated tests
• Tested Client: Has been manually tested in at least one LSP client editor

Method	Basic Impl	Capabilities	Tests	Tested Client	Notes
initialize	✅	✅	✅	✅	trace and other options NYI
initialized	✅	✅	✅	✅
shutdown	✅	✅	✅	✅	supported but does nothing
exit
$/cancelRequest					ignored (unsupported)
window/showMessage	✅
window/showMessageRequest
window/logMessage	✅
telemetry/event
client/registerCapability					unused, but should be used for DocumentSelector at least
client/unregisterCapability
workspace/workspaceFolders
workspace/didChangeWorkspaceFolders	✅	✅	✅	✅
workspace/configuration
workspace/didChangeWatchedFiles					unused, server does own watching
workspace/symbol	✅	✅	✅	✅
workspace/executeCommand	✅	✅	✅	✅
workspace/applyEdit	✅	✅	✅	✅
textDocument/didOpen	✅	✅	✅	✅
textDocument/didChange	✅	✅	✅	✅
textDocument/willSave
textDocument/willSaveWaitUntil
textDocument/didClose	✅	✅	✅	✅
textDocument/publishDiagnostics	✅	✅	✅	✅
textDocument/completion	✅	✅	✅	✅
completionItem/resolve					not required
textDocument/hover	✅	✅	✅	✅
textDocument/signatureHelp	✅	✅	✅	✅	trigger character handling outstanding
textDocument/declaration
textDocument/definition	✅	✅	✅	✅
textDocument/typeDefinition
textDocument/implementation	✅	✅	✅	✅
textDocument/references	✅	✅	✅	✅
textDocument/documentHighlight	✅	✅	✅	✅
textDocument/documentSymbol	✅	✅	✅	✅
textDocument/codeAction (sortMembers)	✅	✅	✅	✅
textDocument/codeAction (organiseImports)	✅	✅	✅	✅
textDocument/codeAction (refactors)
textDocument/codeAction (assists)	✅	✅	✅	✅	Only if the client advertises codeActionLiteralSupport with Refactor
textDocument/codeAction (fixes)	✅	✅	✅	✅	Only if the client advertises codeActionLiteralSupport with QuickFix
textDocument/codeLens
codeLens/resolve
textDocument/documentLink
documentLink/resolve
textDocument/documentColor
textDocument/colorPresentation
textDocument/formatting	✅	✅	✅	✅
textDocument/rangeFormatting					requires support from dart_style?
textDocument/onTypeFormatting	✅	✅	✅	✅
textDocument/rename	✅	✅	✅	✅
textDocument/prepareRename
textDocument/foldingRange	✅	✅	✅	✅

Custom Methods

The following custom methods are also provided by the Dart LSP server:

dart/diagnosticServer Method

Direction: Client -> Server Params: None Returns: { port: number }

Starts the analzyer diagnostics server (if not already running) and returns the port number it's listening on.

$/analyzerStatus Notification

Direction: Server -> Client Params: { isAnalyzing: boolean }

Notifies the client when analysis starts/completes.