For general server architecture, see README.md. For details of IPC communication, see Watchdog.lean. This module implements per-file worker processes.

File processing and requests+notifications against a file should be concurrent for two reasons:

• By the LSP standard, requests should be cancellable.
• Since Lean allows arbitrary user code to be executed during elaboration via the tactic framework, elaboration can be extremely slow and even not halt in some cases. Users should be able to work with the file while this is happening, e.g. make new changes to the file or send requests.

To achieve these goals, elaboration is executed in a chain of tasks, where each task corresponds to the elaboration of one command. When the elaboration of one command is done, the next task is spawned. On didChange notifications, we search for the task in which the change occurred. If we stumble across a task that has not yet finished before finding the task we're looking for, we terminate it and start the elaboration there, otherwise we start the elaboration at the task where the change occurred.

Requests iterate over tasks until they find the command that they need to answer the request. In order to not block the main thread, this is done in a request task. If a task that the request task waits for is terminated, a change occurred somewhere before the command that the request is looking for and the request sends a "content changed" error.

structure Lean.Server.FileWorker.WorkerContext : Type

• chanOut : IO.Channel Lean.JsonRpc.Message

  Synchronized output channel for LSP messages. Notifications for outdated versions are discarded on read.

• maxDocVersionRef : IO.Ref Int

  Latest document version received by the client, used for filtering out notifications from previous versions.

• freshRequestIdRef : IO.Ref Int
• chanIsProcessing : IO.Channel Bool

  Channel that receives a message for every a $/lean/fileProgress notification, indicating whether the notification suggests that the file is currently being processed.

• stickyDiagnosticsRef : IO.Ref (Array Lean.Widget.InteractiveDiagnostic)

  Diagnostics that are included in every single textDocument/publishDiagnostics notification.

• hLog : IO.FS.Stream
• initParams : Lean.Lsp.InitializeParams
• processor : Lean.Parser.InputContext → BaseIO Lean.Language.Lean.InitialSnapshot
• clientHasWidgets : Bool
• cmdlineOpts : Lean.Options

  Options defined on the worker cmdline (i.e. not including options from setup-file), used for context-free tasks such as editing delay.

Asynchronous snapshot elaboration

instance Lean.Server.FileWorker.instInhabitedReportSnapshotsState : Inhabited Lean.Server.FileWorker.ReportSnapshotsState

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opaque Lean.Server.FileWorker.server.reportDelayMs : Lean.Option Nat

structure Lean.Server.FileWorker.MemorizedInteractiveDiagnostics : Type

Type of state stored in Snapshot.Diagnostics.cacheRef?.

See also section "Communication" in Lean/Server/README.md.

• diags : Array Lean.Widget.InteractiveDiagnostic

instance Lean.Server.FileWorker.instTypeNameMemorizedInteractiveDiagnostics : TypeName Lean.Server.FileWorker.MemorizedInteractiveDiagnostics

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• Lean.Server.FileWorker.instTypeNameMemorizedInteractiveDiagnostics = Lean.Server.FileWorker.inst✝

@[reducible, inline]

abbrev Lean.Server.FileWorker.PendingRequestMap : Type

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• Lean.Server.FileWorker.PendingRequestMap = Lean.RBMap Lean.JsonRpc.RequestID (Task (Except IO.Error Unit)) compare

structure Lean.Server.FileWorker.AvailableImportsCache : Type

• availableImports : ImportCompletion.AvailableImports
• lastRequestTimestampMs : Nat

structure Lean.Server.FileWorker.WorkerState : Type

• doc : Lean.Server.FileWorker.EditableDocument
• reporterCancelTk : IO.CancelToken

  Token flagged for aborting doc.reporter when a new document version comes in.

• srcSearchPathTask : Task Lean.SearchPath
• importCachingTask? : Option (Task (Except IO.Error Lean.Server.FileWorker.AvailableImportsCache))
• pendingRequests : Lean.Server.FileWorker.PendingRequestMap
• rpcSessions : Lean.RBMap UInt64 (IO.Ref Lean.Server.FileWorker.RpcSession) compare

  A map of RPC session IDs. We allow asynchronous elab tasks and request handlers to modify sessions. A single Ref ensures atomic transactions.

@[reducible, inline]

abbrev Lean.Server.FileWorker.WorkerM (α : Type) : Type

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• Lean.Server.FileWorker.WorkerM = ReaderT Lean.Server.FileWorker.WorkerContext (StateRefT' IO.RealWorld Lean.Server.FileWorker.WorkerState IO)

def Lean.Server.FileWorker.setupImports (meta : Lean.Server.DocumentMeta) (cmdlineOpts : Lean.Options) (chanOut : IO.Channel Lean.JsonRpc.Message) (srcSearchPathPromise : IO.Promise Lean.SearchPath) (stx : Lean.Syntax) : Lean.Language.ProcessingT IO (Except Lean.Language.Lean.HeaderProcessedSnapshot Lean.Language.Lean.SetupImportsResult)

Callback from Lean language processor after parsing imports that requests necessary information from Lake for processing imports.

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def Lean.Server.FileWorker.initializeWorker (meta : Lean.Server.DocumentMeta) (o : IO.FS.Stream) (e : IO.FS.Stream) (initParams : Lean.Lsp.InitializeParams) (opts : Lean.Options) : IO (Lean.Server.FileWorker.WorkerContext × Lean.Server.FileWorker.WorkerState)

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def Lean.Server.FileWorker.initializeWorker.mkLspOutputChannel (o : IO.FS.Stream) (maxDocVersion : IO.Ref Int) (chanIsProcessing : IO.Channel Bool) : IO (IO.Channel Lean.JsonRpc.Message)

Creates an LSP message output channel along with a reader that sends out read messages on the output FS stream after discarding outdated notifications. This is the only component of the worker with access to the output stream, so we can synchronize messages from parallel elaboration tasks here.

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def Lean.Server.FileWorker.initializeWorker.getImportClosure? (snap : Lean.Language.Lean.InitialSnapshot) : Array Lake.Name

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def Lean.Server.FileWorker.sendServerRequest {α : Type u_1} [Lean.ToJson α] (ctx : Lean.Server.FileWorker.WorkerContext) (method : String) (param : α) : IO Unit

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def Lean.Server.FileWorker.updatePendingRequests (map : Lean.Server.FileWorker.PendingRequestMap → Lean.Server.FileWorker.PendingRequestMap) : Lean.Server.FileWorker.WorkerM Unit

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def Lean.Server.FileWorker.updateDocument (meta : Lean.Server.DocumentMeta) : Lean.Server.FileWorker.WorkerM Unit

Given the new document, updates editable doc state.

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def Lean.Server.FileWorker.handleDidChange (p : Lean.Lsp.DidChangeTextDocumentParams) : Lean.Server.FileWorker.WorkerM Unit

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def Lean.Server.FileWorker.handleCancelRequest (p : Lean.Lsp.CancelParams) : Lean.Server.FileWorker.WorkerM Unit

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def Lean.Server.FileWorker.handleStaleDependency : Lean.Lsp.LeanStaleDependencyParams → Lean.Server.FileWorker.WorkerM Unit

Received from the watchdog when a dependency of this file is detected as being stale. Issues a sticky diagnostic to the client that it should run "Restart File".

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def Lean.Server.FileWorker.handleRpcRelease (p : Lean.Lsp.RpcReleaseParams) : Lean.Server.FileWorker.WorkerM Unit

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def Lean.Server.FileWorker.handleRpcKeepAlive (p : Lean.Lsp.RpcKeepAliveParams) : Lean.Server.FileWorker.WorkerM Unit

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Requests here are handled synchronously rather than in the asynchronous RequestM.

def Lean.Server.FileWorker.handleRpcConnect : Lean.Lsp.RpcConnectParams → Lean.Server.FileWorker.WorkerM Lean.Lsp.RpcConnected

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def Lean.Server.FileWorker.parseParams (paramType : Type) [Lean.FromJson paramType] (params : Lean.Json) : Lean.Server.FileWorker.WorkerM paramType

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def Lean.Server.FileWorker.handleNotification (method : String) (params : Lean.Json) : Lean.Server.FileWorker.WorkerM Unit

def Lean.Server.FileWorker.queueRequest (id : Lean.JsonRpc.RequestID) (requestTask : Task (Except IO.Error Unit)) : Lean.Server.FileWorker.WorkerM Unit

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def Lean.Server.FileWorker.handleGetInteractiveDiagnosticsRequest (params : Lean.Widget.GetInteractiveDiagnosticsParams) : Lean.Server.FileWorker.WorkerM (Array Lean.Widget.InteractiveDiagnostic)

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def Lean.Server.FileWorker.handleImportCompletionRequest (id : Lean.JsonRpc.RequestID) (params : Lean.Lsp.CompletionParams) : Lean.Server.FileWorker.WorkerM (Task (Except IO.Error Lean.Server.FileWorker.AvailableImportsCache))

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def Lean.Server.FileWorker.handleRequest (id : Lean.JsonRpc.RequestID) (method : String) (params : Lean.Json) : Lean.Server.FileWorker.WorkerM Unit

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def Lean.Server.FileWorker.handleResponse : Lean.JsonRpc.RequestID → Lean.Json → Lean.Server.FileWorker.WorkerM Unit

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• Lean.Server.FileWorker.handleResponse x✝ x = pure PUnit.unit

partial def Lean.Server.FileWorker.mainLoop (hIn : IO.FS.Stream) : Lean.Server.FileWorker.WorkerM Unit

def Lean.Server.FileWorker.runRefreshTask : Lean.Server.FileWorker.WorkerM (Task (Except IO.Error Unit))

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def Lean.Server.FileWorker.initAndRunWorker (i : IO.FS.Stream) (o : IO.FS.Stream) (e : IO.FS.Stream) (opts : Lean.Options) : IO UInt32

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def Lean.Server.FileWorker.initAndRunWorker.writeError (e : IO.FS.Stream) (meta : Lean.Server.DocumentMeta) (err : IO.Error) : IO Unit

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@[export lean_server_worker_main]

def Lean.Server.FileWorker.workerMain (opts : Lean.Options) : IO UInt32

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