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

Running the Server

The analysis server snapshot is included in the bin/snapshots folder of the Dart SDK. Pass the --lsp flag to start the server in LSP mode:

dart bin/snapshots/analysis_server.dart.snapshot --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.
  • closingLabels: When set to true, dart/textDocument/publishClosingLabels notifications will be sent with information to render editor closing labels.

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
MethodBasic ImplCapabilitiesTestsTested ClientNotes
initializetrace and other options NYI
initialized
shutdownsupported but does nothing
exit
$/cancelRequest
window/showMessage
window/showMessageRequest
window/logMessage
telemetry/event
client/registerCapability
client/unregisterCapability(unused, capabilities don't change currently)
workspace/workspaceFolders
workspace/didChangeWorkspaceFolders
workspace/configuration
workspace/didChangeWatchedFilesunused, 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
textDocument/hover
textDocument/signatureHelptrigger 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/rangeFormattingrequires 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.

dart/textDocument/super Method

Direction: Client -> Server Params: TextDocumentPositionParams Returns: Location | null

Returns the location of the super definition of the class or method at the provided position or null if there isn't one.

$/analyzerStatus Notification

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

Notifies the client when analysis starts/completes.

dart/textDocument/publishClosingLabels Notification

Direction: Server -> Client Params: { uri: string, abels: { label: string, range: Range }[] }

Notifies the client when closing label information is available (or updated) for a file.