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Merged
andrewbranch merged 6 commits into from
Feb 13, 2026
+105 −85
Merged

Acquire snapshots synchronously while blocking other requests/notifications #2765

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255e98f
Acquire snapshots synchronously while blocking other requests/notific…
andrewbranch Feb 12, 2026
339460f
Merge main into bug/2690 and resolve conflicts
andrewbranch Feb 12, 2026
bbb3f2b
Move pendingClientRequests deletion to defer after async work
andrewbranch Feb 12, 2026
11d55c5
Fix merge
andrewbranch Feb 12, 2026
8e492b5
Keep requests cancelable until async work is done
andrewbranch Feb 12, 2026
8b7a5c5
Merge branch 'main' into bug/2690
andrewbranch Feb 13, 2026
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190 changes: 105 additions & 85 deletions internal/lsp/server.go
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Original file line number Diff line number Diff line change
Expand Up @@ -424,32 +424,40 @@ func (s *Server) dispatchLoop(ctx context.Context) error {
s.pendingClientRequestsMu.Unlock()
}

handle := func() {
if err := s.handleRequestOrNotification(requestCtx, req); err != nil {
if errors.Is(err, context.Canceled) {
if err := s.sendError(req.ID, lsproto.ErrorCodeRequestCancelled); err != nil {
lspExit(err)
}
} else if errors.Is(err, io.EOF) {
lspExit(nil)
} else {
if err := s.sendError(req.ID, err); err != nil {
lspExit(err)
}
handleError := func(err error) {
if errors.Is(err, context.Canceled) {
if err := s.sendError(req.ID, lsproto.ErrorCodeRequestCancelled); err != nil {
lspExit(err)
}
} else if errors.Is(err, io.EOF) {
lspExit(nil)
} else {
if err := s.sendError(req.ID, err); err != nil {
lspExit(err)
}
}
}

removeRequest := func() {
if req.ID != nil {
s.pendingClientRequestsMu.Lock()
defer s.pendingClientRequestsMu.Unlock()
delete(s.pendingClientRequests, *req.ID)
s.pendingClientRequestsMu.Unlock()
}
}

if isBlockingMethod(req.Method) {
handle()
if doAsyncWork, err := s.handleRequestOrNotification(requestCtx, req); err != nil {
handleError(err)
removeRequest()
} else if doAsyncWork != nil {
go func() {
if lsError := doAsyncWork(); lsError != nil {
handleError(lsError)
}
removeRequest()
}()
} else {
go handle()
removeRequest()
}
}
}
Expand Down Expand Up @@ -547,24 +555,46 @@ func (s *Server) send(msg *lsproto.Message) error {
}
}

func (s *Server) handleRequestOrNotification(ctx context.Context, req *lsproto.RequestMessage) error {
// handleRequestOrNotification looks up the handler for the given request or notification, executes its synchronous work
// and returns any asynchronous work as a function to be executed by the caller.
func (s *Server) handleRequestOrNotification(ctx context.Context, req *lsproto.RequestMessage) (func() error, error) {
ctx = lsproto.WithClientCapabilities(ctx, &s.clientCapabilities)

if handler := handlers()[req.Method]; handler != nil {
start := time.Now()
err := handler(s, ctx, req)
doAsyncWork, err := handler(s, ctx, req)
idStr := ""
if req.ID != nil {
idStr = " (" + req.ID.String() + ")"
}
if err != nil {
s.logger.Error("error handling method '", req.Method, "'", idStr, ": ", err)
return nil, err
}
if doAsyncWork != nil {
return func() error {
if ctx.Err() != nil {
return ctx.Err()
}
asyncWorkErr := doAsyncWork()
s.logger.Info(core.IfElse(asyncWorkErr != nil, "error handling method '", "handled method '"), req.Method, "'", idStr, " in ", time.Since(start))
return asyncWorkErr
}, nil
}
s.logger.Info("handled method '", req.Method, "'", idStr, " in ", time.Since(start))
return err
return nil, nil
}
s.logger.Warn("unknown method '", req.Method, "'")
return s.sendError(req.ID, lsproto.ErrorCodeInvalidRequest)
if req.ID != nil {
return nil, s.sendError(req.ID, lsproto.ErrorCodeInvalidRequest)
}
return nil, nil
}

type handlerMap map[lsproto.Method]func(*Server, context.Context, *lsproto.RequestMessage) error
// handlerMap maps LSP method to a handler function. The handler function executes any work that must be done synchronously
// before other requests/notifications can be processed, and returns any additional work as a function to be executed
// asynchronously after the synchronous work is complete.
type handlerMap map[lsproto.Method]func(*Server, context.Context, *lsproto.RequestMessage) (func() error, error)

var handlers = sync.OnceValue(func() handlerMap {
handlers := make(handlerMap)
Expand Down Expand Up @@ -627,9 +657,9 @@ var handlers = sync.OnceValue(func() handlerMap {
})

func registerNotificationHandler[Req any](handlers handlerMap, info lsproto.NotificationInfo[Req], fn func(*Server, context.Context, Req) error) {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) error {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) (func() error, error) {
if s.session == nil && req.Method != lsproto.MethodInitialized {
return lsproto.ErrorCodeServerNotInitialized
return nil, lsproto.ErrorCodeServerNotInitialized
}

var params Req
Expand All @@ -638,9 +668,9 @@ func registerNotificationHandler[Req any](handlers handlerMap, info lsproto.Noti
params = req.Params.(Req)
}
if err := fn(s, ctx, params); err != nil {
return err
return nil, err
}
return ctx.Err()
return nil, ctx.Err()
}
}

Expand All @@ -649,9 +679,9 @@ func registerRequestHandler[Req, Resp any](
info lsproto.RequestInfo[Req, Resp],
fn func(*Server, context.Context, Req, *lsproto.RequestMessage) (Resp, error),
) {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) error {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) (func() error, error) {
if s.session == nil && req.Method != lsproto.MethodInitialize {
return lsproto.ErrorCodeServerNotInitialized
return nil, lsproto.ErrorCodeServerNotInitialized
}

var params Req
Expand All @@ -661,71 +691,75 @@ func registerRequestHandler[Req, Resp any](
}
resp, err := fn(s, ctx, params, req)
if err != nil {
return err
return nil, err
}
if ctx.Err() != nil {
return ctx.Err()
return nil, ctx.Err()
}
return s.sendResult(req.ID, resp)
return nil, s.sendResult(req.ID, resp)
}
}

func registerLanguageServiceDocumentRequestHandler[Req lsproto.HasTextDocumentURI, Resp any](handlers handlerMap, info lsproto.RequestInfo[Req, Resp], fn func(*Server, context.Context, *ls.LanguageService, Req) (Resp, error)) {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) error {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) (func() error, error) {
var params Req
// Ignore empty params.
if req.Params != nil {
params = req.Params.(Req)
}
ls, err := s.session.GetLanguageService(ctx, params.TextDocumentURI())
if err != nil {
return err
}
defer s.recover(ctx, req)
resp, err := fn(s, ctx, ls, params)
if err != nil {
return err
return nil, err
}
if ctx.Err() != nil {
return ctx.Err()
}
return s.sendResult(req.ID, resp)
return func() error {
defer s.recover(ctx, req)
resp, lsErr := fn(s, ctx, ls, params)
if lsErr != nil {
return lsErr
}
if ctx.Err() != nil {
return ctx.Err()
}
return s.sendResult(req.ID, resp)
}, nil
}
}

func registerLanguageServiceWithAutoImportsRequestHandler[Req lsproto.HasTextDocumentURI, Resp any](handlers handlerMap, info lsproto.RequestInfo[Req, Resp], fn func(*Server, context.Context, *ls.LanguageService, Req) (Resp, error)) {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) error {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) (func() error, error) {
var params Req
// Ignore empty params.
if req.Params != nil {
params = req.Params.(Req)
}
languageService, err := s.session.GetLanguageService(ctx, params.TextDocumentURI())
if err != nil {
return err
return nil, err
}
defer s.recover(ctx, req)
resp, err := fn(s, ctx, languageService, params)
if errors.Is(err, ls.ErrNeedsAutoImports) {
languageService, err = s.session.GetLanguageServiceWithAutoImports(ctx, params.TextDocumentURI())
if err != nil {
return err
return func() error {
defer s.recover(ctx, req)
resp, lsErr := fn(s, ctx, languageService, params)
if errors.Is(lsErr, ls.ErrNeedsAutoImports) {
languageService, lsErr = s.session.GetLanguageServiceWithAutoImports(ctx, params.TextDocumentURI())
if lsErr != nil {
return lsErr
}
if ctx.Err() != nil {
return ctx.Err()
}
resp, lsErr = fn(s, ctx, languageService, params)
if errors.Is(lsErr, ls.ErrNeedsAutoImports) {
panic(info.Method + " returned ErrNeedsAutoImports even after enabling auto imports")
}
}
if lsErr != nil {
return lsErr
}
if ctx.Err() != nil {
return ctx.Err()
}
resp, err = fn(s, ctx, languageService, params)
if errors.Is(err, ls.ErrNeedsAutoImports) {
panic(info.Method + " returned ErrNeedsAutoImports even after enabling auto imports")
}
}
if err != nil {
return err
}
if ctx.Err() != nil {
return ctx.Err()
}
return s.sendResult(req.ID, resp)
return s.sendResult(req.ID, resp)
}, nil
}
}

Expand All @@ -734,7 +768,7 @@ func registerMultiProjectReferenceRequestHandler[Req lsproto.HasTextDocumentPosi
info lsproto.RequestInfo[Req, Resp],
fn func(*ls.LanguageService, context.Context, Req, ls.CrossProjectOrchestrator) (Resp, error),
) {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) error {
handlers[info.Method] = func(s *Server, ctx context.Context, req *lsproto.RequestMessage) (func() error, error) {
var params Req
// Ignore empty params.
if req.Params != nil {
Expand All @@ -743,14 +777,16 @@ func registerMultiProjectReferenceRequestHandler[Req lsproto.HasTextDocumentPosi
// !!! sheetal: multiple projects that contain the file through symlinks
defaultLs, orchestrator, err := s.getLanguageServiceAndCrossProjectOrchestrator(ctx, params.TextDocumentURI(), req)
if err != nil {
return err
return nil, err
}
defer s.recover(ctx, req)
resp, err := fn(defaultLs, ctx, params, orchestrator)
if err != nil {
return err
}
return s.sendResult(req.ID, resp)
return func() error {
defer s.recover(ctx, req)
resp, lsErr := fn(defaultLs, ctx, params, orchestrator)
if lsErr != nil {
return lsErr
}
return s.sendResult(req.ID, resp)
}, nil
}
}

Expand Down Expand Up @@ -1355,22 +1391,6 @@ func (s *Server) NpmInstall(cwd string, args []string) ([]byte, error) {
return s.npmInstall(cwd, args)
}

func isBlockingMethod(method lsproto.Method) bool {
switch method {
case lsproto.MethodInitialize,
lsproto.MethodInitialized,
lsproto.MethodTextDocumentDidOpen,
lsproto.MethodTextDocumentDidChange,
lsproto.MethodTextDocumentDidSave,
lsproto.MethodTextDocumentDidClose,
lsproto.MethodWorkspaceDidChangeWatchedFiles,
lsproto.MethodWorkspaceDidChangeConfiguration,
lsproto.MethodWorkspaceConfiguration:
return true
}
return false
}

// Developer/debugging command handlers

func (s *Server) handleRunGC(_ context.Context, _ any, _ *lsproto.RequestMessage) (lsproto.RunGCResponse, error) {
Expand Down