feat(configfileregistry): optimize config discovery

Refactor hot paths in project setup for better performance and simplicity.

- Config acquisition and parsing: Add fast-path for already-parsed configs, deduplicate concurrent parses using a wait group, use narrower locks (read locks for reads, write locks only for updates), avoid full reloads on entry creation, and support targeted reloads (file lists only).
- Default project discovery: Replace recursive goroutine-based traversal with a single-threaded iterative BFS queue. Track visited paths by (path, loadKind) pair, upgrade loadKind monotonically, and exit early on a good match. This removes recursion depth issues, goroutine overload, and sync overhead, while making resolution deterministic.
- Result tracking and service wiring: Use a single mutex with plain maps instead of SyncMaps and multiple locks. Ensure monotonic updates to prevent revisits with weaker loadKind. Initialize activeParsing in NewService and make cleanup consistent with BFS using plain maps under mutex.

These changes eliminate duplicate parsing, cut CPU spikes, and avoid goroutine storms in large reference graphs. The design now scales linearly with project size and offers more predictable latency under load.

Performance:

Old design: O(E) goroutines (E = edges in tsconfig graph), with duplicate work on converging paths. Parsing was O(N * c) worst-case (N = configs, c = concurrent requests per config).

New design: O(V + E) traversal (V = tsconfigs), visiting each config once per strongest loadKind. Parsing is O(N) amortized, as each config parses only once.

See oxc-project/tsgolint#99 for before/after analysis.

Author: camc314

internal/api/api.go

@@ -65,9 +65,9 @@ func NewAPI(host APIHost, options APIOptions) *API {
 		},
 	})
 
-	api.configFileRegistry = &project.ConfigFileRegistry{
+	api.configFileRegistry = project.NewConfigFileRegistry(&project.ConfigFileRegistry{
 		Host: api,
-	}
+	})
 	return api
 }
 

internal/project/configfileregistry.go

@@ -28,12 +28,24 @@ type ExtendedConfigFileEntry struct {
 	configFiles collections.Set[tspath.Path]
 }
 
+type parseStatus struct {
+	wg *sync.WaitGroup
+}
+
 type ConfigFileRegistry struct {
 	Host                  ProjectHost
 	defaultProjectFinder  *defaultProjectFinder
 	ConfigFiles           collections.SyncMap[tspath.Path, *ConfigFileEntry]
 	ExtendedConfigCache   collections.SyncMap[tspath.Path, *tsoptions.ExtendedConfigCacheEntry]
 	ExtendedConfigsUsedBy collections.SyncMap[tspath.Path, *ExtendedConfigFileEntry]
+
+	parseMu       sync.Mutex
+	activeParsing map[tspath.Path]*parseStatus
+}
+
+func NewConfigFileRegistry(registry *ConfigFileRegistry) *ConfigFileRegistry {
+	registry.activeParsing = make(map[tspath.Path]*parseStatus)
+	return registry
 }
 
 func (e *ConfigFileEntry) SetPendingReload(level PendingReload) bool {
@@ -74,41 +86,99 @@ func (c *ConfigFileRegistry) releaseConfig(path tspath.Path, project *Project) {
 }
 
 func (c *ConfigFileRegistry) acquireConfig(fileName string, path tspath.Path, project *Project, info *ScriptInfo) *tsoptions.ParsedCommandLine {
-	entry, ok := c.ConfigFiles.Load(path)
-	if !ok {
-		// Create parsed command line
+	if entry, ok := c.ConfigFiles.Load(path); ok {
+		entry.mu.RLock()
+		needsReload := entry.pendingReload != PendingReloadNone
+		commandLine := entry.commandLine
+		entry.mu.RUnlock()
+
+		if !needsReload && commandLine != nil {
+			entry.mu.Lock()
+			if project != nil {
+				entry.projects.Add(project)
+			} else if info != nil {
+				entry.infos.Add(info)
+			}
+			entry.mu.Unlock()
+			return commandLine
+		}
+	}
+
+	c.parseMu.Lock()
+	if status, ok := c.activeParsing[path]; ok {
+		c.parseMu.Unlock()
+		status.wg.Wait()
+
+		if entry, ok := c.ConfigFiles.Load(path); ok {
+			entry.mu.Lock()
+			defer entry.mu.Unlock()
+			if project != nil {
+				entry.projects.Add(project)
+			} else if info != nil {
+				entry.infos.Add(info)
+			}
+			return entry.commandLine
+		}
+	}
+
+	status := &parseStatus{wg: &sync.WaitGroup{}}
+	status.wg.Add(1)
+	c.activeParsing[path] = status
+	c.parseMu.Unlock()
+
+	defer func() {
+		status.wg.Done()
+		c.parseMu.Lock()
+		delete(c.activeParsing, path)
+		c.parseMu.Unlock()
+	}()
+
+	entry, loaded := c.ConfigFiles.Load(path)
+	if !loaded {
 		config, _ := tsoptions.GetParsedCommandLineOfConfigFilePath(fileName, path, nil, c.Host, &c.ExtendedConfigCache)
 		var rootFilesWatch *watchedFiles[[]string]
 		client := c.Host.Client()
 		if c.Host.IsWatchEnabled() && client != nil {
-			rootFilesWatch = newWatchedFiles(&configFileWatchHost{fileName: fileName, host: c.Host}, lsproto.WatchKindChange|lsproto.WatchKindCreate|lsproto.WatchKindDelete, core.Identity, "root files")
+			rootFilesWatch = newWatchedFiles(&configFileWatchHost{fileName: fileName, host: c.Host},
+				lsproto.WatchKindChange|lsproto.WatchKindCreate|lsproto.WatchKindDelete,
+				core.Identity, "root files")
 		}
-		entry, _ = c.ConfigFiles.LoadOrStore(path, &ConfigFileEntry{
+
+		newEntry := &ConfigFileEntry{
 			commandLine:    config,
-			pendingReload:  PendingReloadFull,
+			pendingReload:  PendingReloadNone, // Already parsed, no reload needed
 			rootFilesWatch: rootFilesWatch,
-		})
+		}
+
+		entry, loaded = c.ConfigFiles.LoadOrStore(path, newEntry)
+		if !loaded {
+			c.updateRootFilesWatch(fileName, entry)
+			c.updateExtendedConfigsUsedBy(path, entry, nil)
+		}
 	}
+
 	entry.mu.Lock()
 	defer entry.mu.Unlock()
+
 	if project != nil {
 		entry.projects.Add(project)
 	} else if info != nil {
 		entry.infos.Add(info)
 	}
-	if entry.pendingReload == PendingReloadNone {
-		return entry.commandLine
-	}
-	switch entry.pendingReload {
-	case PendingReloadFileNames:
-		entry.commandLine = entry.commandLine.ReloadFileNamesOfParsedCommandLine(c.Host.FS())
-	case PendingReloadFull:
-		oldCommandLine := entry.commandLine
-		entry.commandLine, _ = tsoptions.GetParsedCommandLineOfConfigFilePath(fileName, path, nil, c.Host, &c.ExtendedConfigCache)
-		c.updateExtendedConfigsUsedBy(path, entry, oldCommandLine)
-		c.updateRootFilesWatch(fileName, entry)
+
+	if entry.pendingReload != PendingReloadNone {
+		switch entry.pendingReload {
+		case PendingReloadFileNames:
+			entry.commandLine = entry.commandLine.ReloadFileNamesOfParsedCommandLine(c.Host.FS())
+		case PendingReloadFull:
+			oldCommandLine := entry.commandLine
+			entry.commandLine, _ = tsoptions.GetParsedCommandLineOfConfigFilePath(fileName, path, nil, c.Host, &c.ExtendedConfigCache)
+			c.updateExtendedConfigsUsedBy(path, entry, oldCommandLine)
+			c.updateRootFilesWatch(fileName, entry)
+		}
+		entry.pendingReload = PendingReloadNone
 	}
-	entry.pendingReload = PendingReloadNone
+
 	return entry.commandLine
 }
 
@@ -164,17 +234,19 @@ func (c *ConfigFileRegistry) updateExtendedConfigsUsedBy(path tspath.Path, entry
 		extendedEntry.configFiles.Add(path)
 		extendedEntry.mu.Unlock()
 	}
-	for _, extendedConfig := range oldCommandLine.ExtendedSourceFiles() {
-		extendedPath := tspath.ToPath(extendedConfig, c.Host.GetCurrentDirectory(), c.Host.FS().UseCaseSensitiveFileNames())
-		if !slices.Contains(newConfigs, extendedPath) {
-			extendedEntry, _ := c.ExtendedConfigsUsedBy.Load(extendedPath)
-			extendedEntry.mu.Lock()
-			extendedEntry.configFiles.Delete(path)
-			if extendedEntry.configFiles.Len() == 0 {
-				c.ExtendedConfigsUsedBy.Delete(extendedPath)
-				c.ExtendedConfigCache.Delete(extendedPath)
+	if oldCommandLine != nil {
+		for _, extendedConfig := range oldCommandLine.ExtendedSourceFiles() {
+			extendedPath := tspath.ToPath(extendedConfig, c.Host.GetCurrentDirectory(), c.Host.FS().UseCaseSensitiveFileNames())
+			if !slices.Contains(newConfigs, extendedPath) {
+				extendedEntry, _ := c.ExtendedConfigsUsedBy.Load(extendedPath)
+				extendedEntry.mu.Lock()
+				extendedEntry.configFiles.Delete(path)
+				if extendedEntry.configFiles.Len() == 0 {
+					c.ExtendedConfigsUsedBy.Delete(extendedPath)
+					c.ExtendedConfigCache.Delete(extendedPath)
+				}
+				extendedEntry.mu.Unlock()
 			}
-			extendedEntry.mu.Unlock()
 		}
 	}
 }

internal/project/defaultprojectfinder.go

@@ -5,7 +5,6 @@ import (
 	"strings"
 	"sync"
 
-	"github.com/microsoft/typescript-go/internal/collections"
 	"github.com/microsoft/typescript-go/internal/core"
 	"github.com/microsoft/typescript-go/internal/tsoptions"
 	"github.com/microsoft/typescript-go/internal/tspath"
@@ -190,33 +189,81 @@ func (f *defaultProjectFinder) tryFindDefaultConfiguredProjectFromReferences(
 	if len(config.ProjectReferences()) == 0 {
 		return false
 	}
-	wg := core.NewWorkGroup(false)
-	f.tryFindDefaultConfiguredProjectFromReferencesWorker(info, config, loadKind, result, wg)
-	wg.RunAndWait()
-	return result.isDone()
-}
 
-func (f *defaultProjectFinder) tryFindDefaultConfiguredProjectFromReferencesWorker(
-	info *ScriptInfo,
-	config *tsoptions.ParsedCommandLine,
-	loadKind projectLoadKind,
-	result *openScriptInfoProjectResult,
-	wg core.WorkGroup,
-) {
+	type configItem struct {
+		fileName string
+		path     tspath.Path
+		config   *tsoptions.ParsedCommandLine
+		loadKind projectLoadKind
+	}
+
+	type visitKey struct {
+		path     tspath.Path
+		loadKind projectLoadKind
+	}
+
+	var queue []configItem
+	visited := make(map[visitKey]bool)
+
+	initialLoadKind := loadKind
 	if config.CompilerOptions().DisableReferencedProjectLoad.IsTrue() {
-		loadKind = projectLoadKindFind
+		initialLoadKind = projectLoadKindFind
 	}
+
 	for _, childConfigFileName := range config.ResolvedProjectReferencePaths() {
-		wg.Queue(func() {
+		childConfigFilePath := f.service.toPath(childConfigFileName)
+		key := visitKey{path: childConfigFilePath, loadKind: initialLoadKind}
+		if !visited[key] {
+			visited[key] = true
+			childConfig := f.findOrAcquireConfig(info, childConfigFileName, childConfigFilePath, initialLoadKind)
+			if childConfig != nil {
+				queue = append(queue, configItem{
+					fileName: childConfigFileName,
+					path:     childConfigFilePath,
+					config:   childConfig,
+					loadKind: initialLoadKind,
+				})
+			}
+		}
+	}
+
+	for len(queue) > 0 {
+		current := queue[0]
+		queue = queue[1:]
+
+		if f.isDefaultConfigForScriptInfo(info, current.fileName, current.path, current.config, current.loadKind, result) {
+			return true
+		}
+
+		if result.isDone() {
+			return true
+		}
+
+		childLoadKind := current.loadKind
+		if current.config.CompilerOptions().DisableReferencedProjectLoad.IsTrue() {
+			childLoadKind = projectLoadKindFind
+		}
+
+		for _, childConfigFileName := range current.config.ResolvedProjectReferencePaths() {
 			childConfigFilePath := f.service.toPath(childConfigFileName)
-			childConfig := f.findOrAcquireConfig(info, childConfigFileName, childConfigFilePath, loadKind)
-			if childConfig == nil || f.isDefaultConfigForScriptInfo(info, childConfigFileName, childConfigFilePath, childConfig, loadKind, result) {
-				return
+			key := visitKey{path: childConfigFilePath, loadKind: childLoadKind}
+
+			if !visited[key] {
+				visited[key] = true
+				childConfig := f.findOrAcquireConfig(info, childConfigFileName, childConfigFilePath, childLoadKind)
+				if childConfig != nil {
+					queue = append(queue, configItem{
+						fileName: childConfigFileName,
+						path:     childConfigFilePath,
+						config:   childConfig,
+						loadKind: childLoadKind,
+					})
+				}
 			}
-			// Search in references if we cant find default project in current config
-			f.tryFindDefaultConfiguredProjectFromReferencesWorker(info, childConfig, loadKind, result, wg)
-		})
+		}
 	}
+
+	return result.isDone()
 }
 
 func (f *defaultProjectFinder) tryFindDefaultConfiguredProjectFromAncestor(
@@ -318,57 +365,70 @@ func (f *defaultProjectFinder) findDefaultConfiguredProject(scriptInfo *ScriptIn
 }
 
 type openScriptInfoProjectResult struct {
-	projectMu         sync.RWMutex
-	project           *Project
-	fallbackDefaultMu sync.RWMutex
-	fallbackDefault   *Project // use this if we cant find actual project
-	seenProjects      collections.SyncMap[*Project, projectLoadKind]
-	seenConfigs       collections.SyncMap[tspath.Path, projectLoadKind]
+	mu              sync.Mutex
+	project         *Project
+	fallbackDefault *Project // use this if we cant find actual project
+	seenProjects    map[*Project]projectLoadKind
+	seenConfigs     map[tspath.Path]projectLoadKind
 }
 
 func (r *openScriptInfoProjectResult) addSeenProject(project *Project, loadKind projectLoadKind) bool {
-	if kind, loaded := r.seenProjects.LoadOrStore(project, loadKind); loaded {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if r.seenProjects == nil {
+		r.seenProjects = make(map[*Project]projectLoadKind)
+	}
+
+	if kind, exists := r.seenProjects[project]; exists {
 		if kind >= loadKind {
 			return false
 		}
-		r.seenProjects.Store(project, loadKind)
 	}
+	r.seenProjects[project] = loadKind
 	return true
 }
 
 func (r *openScriptInfoProjectResult) addSeenConfig(configPath tspath.Path, loadKind projectLoadKind) bool {
-	if kind, loaded := r.seenConfigs.LoadOrStore(configPath, loadKind); loaded {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if r.seenConfigs == nil {
+		r.seenConfigs = make(map[tspath.Path]projectLoadKind)
+	}
+
+	if kind, exists := r.seenConfigs[configPath]; exists {
 		if kind >= loadKind {
 			return false
 		}
-		r.seenConfigs.Store(configPath, loadKind)
 	}
+	r.seenConfigs[configPath] = loadKind
 	return true
 }
 
 func (r *openScriptInfoProjectResult) isDone() bool {
-	r.projectMu.RLock()
-	defer r.projectMu.RUnlock()
+	r.mu.Lock()
+	defer r.mu.Unlock()
 	return r.project != nil
 }
 
 func (r *openScriptInfoProjectResult) setProject(project *Project) {
-	r.projectMu.Lock()
-	defer r.projectMu.Unlock()
+	r.mu.Lock()
+	defer r.mu.Unlock()
 	if r.project == nil {
 		r.project = project
 	}
 }
 
 func (r *openScriptInfoProjectResult) hasFallbackDefault() bool {
-	r.fallbackDefaultMu.RLock()
-	defer r.fallbackDefaultMu.RUnlock()
+	r.mu.Lock()
+	defer r.mu.Unlock()
 	return r.fallbackDefault != nil
 }
 
 func (r *openScriptInfoProjectResult) setFallbackDefault(project *Project) {
-	r.fallbackDefaultMu.Lock()
-	defer r.fallbackDefaultMu.Unlock()
+	r.mu.Lock()
+	defer r.mu.Unlock()
 	if r.fallbackDefault == nil {
 		r.fallbackDefault = project
 	}